ML23044A098
ML23044A098 | |
Person / Time | |
---|---|
Site: | 07103098 |
Issue date: | 02/10/2023 |
From: | Boyle R, Vescovi P Orano Federal Services, US Dept of Transportation (DOT), Office of Hazardous Materials Safety |
To: | Garcia-Santos N Storage and Transportation Licensing Branch |
References | |
A33010, L-2023-DOT-0002, NFK-MPC-2208001 | |
Download: ML23044A098 (1) | |
Text
NFK-MPC-2208001 Safety Analysis Report GP-01 Nuclear Fuel Industries, Ltd.
July 2022 Shall not disclose this document to any third party without official permission from NFI
CHAPTER I - Description of Nuclear Fuel Package I-A. Purposes and Requirements (1) Application The nuclear fuel package configured with a type GP-01 transport packaging is designed to be used for domestic and international transport of pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium, enriched to 5 weight percent or less for use in light water reactors.
(2) Type designation of packaging: GP-01 (3) Category of package: Type A fissile package (4) Limit to number of packages: No limit (5) Geometrical arrangement required for transport: Arbitrary (6) Transport index: 0.3 (7) Criticality safety index: 0 I-B. Type of Package Type A fissile package I-C. Packaging (1) Gross weight:
- Gross weight of packaging: 730 kg
- Gross weight of package: 1300 kg (2) Structural materials The type GP-01 packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without being dismantled. Essentially, the outer receptacle consists of structural elements including stainless steel frames, inner plates and outer plates.
These structural elements are provided with heat insulating material made of ceramic fiber and spacers made of rubber. The inner receptacle consists of stainless steel plates provided with rubber spacers and an O-ring. Table I-1 shows details of the structural elements.
(3) Neutron absorbers The boronic stainless steel plates installed inside the inner receptacle serve as neutron absorbers.
Table I-1 shows these neutron absorbers with detailed structural elements.
(4) Neutron moderators Not applicable.
(5) Shielding material Not applicable.
I-1
(6) Dimensions and constructions of main parts (a) General Fig. I-1 shows a general view of the package considered. The package resembles a nested box and consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without being dismantled. The outer receptacle has a multi-caisson-shaped double structure composed of frames, inner plates, and outer plates. The voids between the inner plates and the outer plates are filled with blocks of a heat insulating material to ensure heat resistance.
Aluminum honeycomb elements are attached to the inner surfaces of the outer receptacle and its lid to attenuate any external shock against the inner receptacle. A fusible plug is installed at an appropriate location on each of the outer faces of the outer receptacle.
The lid of the outer receptacle has the same structure as that of the main body of the outer receptacle. The top surface of the lid has six (6) recesses which mate with six legs of another outer receptacle when a package/packaging is placed in stack on another as required. These six recesses can be used for positioning the upper package/packaging. Four of the six recesses at the four corners of the receptacle have a hole to which a hook or a shackle can be hitched for lifting the entire package. The lid of the outer receptacle is firmly joined to the body of the outer receptacle by means of twenty (20) rod bolts with nuts on the flange. The flange has two seal fixing holes at symmetrical locations.
The body and of inner receptacle as well as the lid of the inner receptacle has a single-caisson-shaped structure composed of thick stainless steel plates. An O-ring is provided for sealing the receptacle on the flange surface. Like the outer receptacle, the lid of the inner receptacle is joined to the body of the inner receptacle by means of sixteen (16) rod bolts. Six boronic stainless steel plates are installed: one on each of the four narrower lateral sides and one on each of the two wider lateral sides; one boronic stainless steel plate is installed as partition between two pellet storage box assemblies (contents of package).
(b) Structure I. Body of outer receptacle Fig. I-2 shows the multi-caisson-shaped structure of the body of the outer receptacle in detail.
The body of the outer receptacle consists of 5-mm thick stainless steel channel skeleton elements formed as multiple caissons on which 3 mm thick stainless steel outer plates and 2 mm thick stainless steel inner plates are welded. The body of the outer receptacle has a length of 1134 mm, a width (breadth) of 820 mm and a height of 894 mm (from leg bottom to flange).
Stainless steel rods 10 mm in thickness and 66 mm in width are welded on the flange. The flange has a shape with an internal portion which is so elevated that rainwater (for example) is prevented from entering the outer receptacle through any gap accidentally created between the body and the lid. Rod bolt seats are provided on the entire lateral sides of the body immediately under the flange. These seats are sufficiently offset from the general surfaces of the outer plates to stay behind them.
Pieces of blanket-like ceramic fiber insulator, cut in appropriate dimensions, are inserted into the gap between the inner plates and the outer plates. Aluminum honeycomb elements are installed on the inner surfaces of the lateral sides and the bottom and are covered and fixed with a 1.5 mm thick aluminum cover. Square pipes (40 mm x 40 mm) of stainless steel are welded on the inner surfaces of the body to protect the inner receptacle flange from external shock in the event of accidental drop. Silicone rubber spacers 5 mm in thickness are applied to the flange. A positioning pin 16 mm in diameter of stainless steel is installed at each of the two diagonally-located corners of the body. Two pieces of 3 mm thick stainless steel are welded on the lowermost portions and bottom of the receptacle to form guards against damage that could potentially be caused by transport devices such as forklifts and pallet trucks during transport.
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II. Lid of outer receptacle Fig. I-3 shows the structure of the lid of the outer receptacle. Like the body of the outer receptacle, the lid of the outer receptacle consists of 5 mm thick stainless steel channel skeleton elements formed as multiple caissons on which stainless steel 3 mm thick outer plates and 2 mm thick stainless steel inner plates are welded. Stainless steel plates 2 mm in thickness are welded on the entire lateral sides of the lid, and stainless steel rods 10 mm in thickness and 63 mm in width are welded on the lower ends of the plates to form a flange. The lid has a length of 1144 mm, a width (breadth) of 830 mm and a height of 166 mm (external dimensions excluding inner honeycomb elements). Channel elements 3 mm in thickness are welded on the upper surface of the flange on the entire lateral sides of the lid to achieve the required strength of the flange. Pieces of 10 mm thick stainless steel plate are welded to form lifting attachments.
Pieces of blanket-like ceramic fiber insulator, cut in the appropriate dimensions, are inserted into the gap between the inner plates and the outer plates and in the void of the channel on the lateral sides. Aluminum honeycomb elements are attached to the inner/bottom surface of the lid and are covered and fixed with a 1.5 mm thick aluminum honeycomb cover. The surface of aluminum honeycomb cover are applied to two (2) anti-interference spacers of neoprene rubber 2 mm in thickness. Pieces of fire-resistant rubber 3 mm in thickness are applied to the inner sides of the flange. These rubber pieces have the capability of expanding in accidental fire conditions to block up the gaps between the elements.
III. Body of inner receptacle Fig. I-4 shows the structure of the body of the inner receptacle. The body consists of pieces of 6 mm thick and 8 mm thick stainless steel plates welded onto each other to form a multi-caisson-shaped construction. Stainless steel rods 12 mm in thickness and 45 or 47 mm in width are machined and welded on the top of the body of the inner receptacle to form a flange. To increase the strength of the flange, rod bolt seats are provided at sixteen (16) points on the entire lateral sides of the body. The flange has a 13 mm wide groove into which an O-ring of silicone rubber 10 mm in diameter is engaged. Silicone rubber spacers 5 mm in thickness are applied to the entire flat surface of the flange. A positioning pin 12 mm in diameter of stainless steel is installed at each of the two diagonally-located corners of the body. The boronic stainless steel plates applied to the entire inner surface of the body with an inorganic adhesive serve as neutron absorbers. The stainless steel partition in the center is boronic, too.
IV. Lid of inner receptacle Fig. I-5 shows the structure of the lid of the inner receptacle. The lid is made of 10 mm thick stainless steel plates. Three 15 mm thick stainless steel bars are welded on the top of the lid to work as reinforcing elements and lifting attachments at the same time. The border of the lid is machined (spot-faced) to serve as the seat into which a fixing nut is engaged. Twelve (12) anti-interference spacers of neoprene rubber 10 mm in thickness are applied to the reverse side of the lid as protecting and fixing materials for the pillars of the pellet storage box assemblies.
V. Neutron absorbers Fig. I-6 shows the positions of the neutron absorbers. These are 3 mm thick boronic (concentration: one weight percent) stainless steel plates fixed with an inorganic adhesive, one on each of the two narrower internal lateral sides and two in parallel on each of the two internal wider lateral sides at positions which correspond to the pellet storage box assemblies (six absorbers in total). Neutron absorbers are also provided like a partition between the two pellet storage box assemblies. This consists of two joined 3 mm thick boronic stainless steel plates and is fixed with countersunk screws by two upper point and two lower points on the fixing blocks welded onto the body of the inner receptacle.
Stainless steel guides are welded onto the inner surfaces of the inner receptacle to avoid accidental friction/collision between materials during loading of the pellet storage box I-3
assemblies into the inner receptacle. The three fixing blocks on top of the central neutron absorber installed in the receptacle center have the shape of a guide. Spacers of neoprene rubber 3 mm in thickness are applied to the surfaces of all the neutron absorbers to prevent friction wear during operation.
VI. Rod bolts The rod bolts used for the bodies of the inner and outer receptacles are of type M16 and identical for both receptacles. These rod bolts are manufactured by forging and machining SCM435 steel. Rod bolts are fixed on the 5 mm thick bolt seats welded onto the body of the inner receptacle or outer receptacle, with hinge pins.
Rod bolts with stainless steel flat washer and stainless steel disk spring are joined to the lid of the receptacle by tightening a stainless steel nut with a wrench.
VII. Legs and skids The leg is manufactured by forming a 4 mm thick stainless steel plate into a 125 x 125 mm square. Legs are welded at six points on the bottom of the body of the outer receptacle. The skid consists of a 5 mm thick stainless steel plate into which a 10 mm thick urethane rubber plate is burnt. The skid is fixed on the bottom surface of each leg with M12 screws.
VIII. Fusible plugs Fig. I-7 shows the structure of the fusible plug. The fusible plug consists of a machined stainless steel rod 31.5 mm in diameter into which solder is cast and which is screwed into a base manufactured from a stainless steel rod 40 mm in diameter. This base is welded in the hole created on the outer plate of the body of the outer receptacle. A fusible plug is installed in the center of each face of the outer receptacle and lid of the outer receptacle (six pieces in total). The melting temperature of solder is approximately 180 °C.
IX. Ancillary elements Two urethane rubber guides are provided on each of the four faces of the body of the inner receptacle to protect the honeycomb elements from damage that could be caused by contact with the bottom edge of an inner receptacle during loading of the latter into an outer receptacle. An MC nylon of high sliding capability is attached to the tip of the guide.
Twelve (12) 8 mm thick anti-vibration rubber plates are applied to the upper surface of the aluminum honeycomb elements on the bottom of the body of the outer receptacle to attenuate potential component of vibration during transport which may be transmitted to the inner receptacle.
(7) Welding Tig welding is adopted for all the elements of the packaging to be welded.
The welds on the frames of the body of the outer receptacle have various shapes: butt welds on flat plates in I-shape or inclined-V-shape, fillet on right-angled portions, single flange on bent portions, and discontinued fillet along the frame between frame and outer plate. Plug welding is selected for a frame to be welded on an inner plate. The flange of the outer receptacle is welded in inclined-V-shape and fillet on the entire perimeter. The outer plates are welded in inclined-V.
The frame of the outer receptacle lid is welded in I-shape or inclined-V-shape on the butt welds of flat plates, as fillet on joints at right angles, and as single flange on bent welds. The frames and outer plates are welded as discontinuous fillet along the frame. Plug welding is adopted for the frames and inner plates. The welds on the flange of outer receptacle lid are in inclined-V shape with the ends of the outer plates, as fillet with reinforcing channel steel, in I-shape with the ends of the outer plates, and as fillet on the split level portions of the lifting attachments.
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The lateral plates of the body of the inner receptacle and the bottom plate are welded in inclined-V-shape, the flange is welded in inclined-V-shape and as fillet.
The reinforcing bars on the inner receptacle lid, which also serve as lifting attachments, are welded as fillets.
(8) Heat extraction No special systems or mechanisms are provided for the packaging since it is designed for containing unirradiated pellets of uranium oxides or unirradiated pellets of uranium oxides mixed with gadolinium, whose calorific values are negligible.
(9) Coolant No coolant is used in or for the packaging since it is designed for containing unirradiated pellets of uranium oxides or unirradiated pellets of uranium oxides mixed with gadolinium, whose calorific values are negligible.
(10) Valves Openings for valves, openings for collecting partial samples of unirradiated pellets of uranium oxides or unirradiated pellets of uranium oxides mixed with gadolinium, or pipes or tubes are not provided in the inner receptacle, which is designed to form a containment boundary of the packaging.
(11) Protruding portions inside and outside the packaging The only protruding portions on the outer surface of the outer receptacle are the legs welded on the bottom of the outer receptacle. The lifting attachments and the rod bolts designed for joining a body of outer receptacle to its lid are installed in recesses created on the receptacle and lid, and therefore have no protruding portions.
There are no protruding portions on the inner surface of the outer receptacle.
Outside the body of the inner receptacle has a flange and rod bolts which protrude from the general surface of the body, but the back of lid of outer receptacle is formed so that the protruding parts of do not directly contact outer receptacle.
(12) Lifting devices The holed attachments on the four corners of the lid of the outer receptacle constitute a set of lifting devices in the packaging. Hoisting tools such as shackles or hooks can be connected to the holes of these lifting attachments, and a crane/chain block can be employed to lift the resulting packaging/tools assembly in an easy and safe manner. The packaging is also designed to be transported on vehicles such as forklifts and pallet trucks. In such cases, the positions between the legs on the bottom of the body of outer receptacle are supported on a transport vehicle for easy and safe handling.
By design, the inner receptacle can be retrieved from the outer receptacle without being dismantled. The bars which serve as both reinforcing element for the lid of the inner receptacle and lifting point constitute a lifting device. Hoisting tools such as shackles or hooks can be connected to the bar for easy and safe lifting. Like the outer receptacle, the inner receptacle is designed to be transported on vehicles such as forklifts and pallet trucks.
(13) Tie-down system The packaging is not equipped with a tie-down system. A packaging to be transported should be tied down with steel wires or dedicated tie-down attachments on a vehicle or a transport container.
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(14) Pressure relief valve The outer receptacle of the packaging is not leaktight and is therefore not equipped with a pressure relief valve to be activated when the inner pressure rises excessively. The inner receptacle has a leaktight structure capable of enduring a certain level of excessive pressures and is not equipped with pressure relief valves.
(15) Gasket The silicone rubber O-ring 10 mm in diameter on the flange of the body of the inner receptacle serves as a gasket. This O-ring is installed (engaged) in the groove 13 mm in width and 7 mm in depth. Rod bolts are tightened to press the lid of the inner receptacle having a flat surface in contact with the O-ring against the O-ring and the body of the receptacle. The O-ring changes its shape and transmits the pressing force of the rod bolts onto the body of the inner receptacle.
Thus, the O-ring serves as a sealing device for the inner receptacle.
(16) Containment boundary The inner receptacle forms a containment boundary. The body of the inner receptacle is open on its entire top before receiving the intended contents. Once the contents are loaded in place in the inner receptacle, the rod bolts are tightened on the lid composed of one single 10 mm thick stainless steel plate to close the lid. Thus, the inner receptacle forms its portion of an actual containment boundary, in contact with the O-ring under load of the tightened rod bolts.
Moreover, continuous welding is adopted for all the joints of the stainless steel lateral plates 6 mm and 8 mm in thickness, the stainless steel bottom plate and the stainless steel flange to complete the desired containment boundary.
(17) Water in-leakage zone Leaktightness is guaranteed for the interior of the inner receptacle which actually forms a containment boundary. The packaging is evaluated in the criticality analysis on the assumption that the fuel zone is exposed to water under normal conditions and under accident conditions.
(18) Containment system The inner receptacle of the packaging forms a perfect containment boundary when all the following processes are complete: loading the contents, welding the receptacle constituent elements and tightening the rod bolts to press the lid/O-ring against the body of the inner receptacle to bring these two elements into tight contact. Therefore, the packaging has no special sealing or containing mechanisms or devices.
I-D. Contents of Packaging The packaging is designed to contain two assemblies of pellet storage boxes which contain pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium. A complete pellet storage box assembly consists of pellet storage boxes stacked alternately with partitions which are penetrated by six pillars. The stacks of the pellet storage boxes are fixed with nuts at the threaded top of the pillars.
Each assembly has a capacity of containing up to 132 kg of UO2 pellets of up to 5 weight percent enrichment. The packaging is designed for use with pellets 8 mm to 10 mm in diameter for fuel assemblies for any types of boiling light water reactors or pressurized light water reactors.
In some cases of loading, pellet storage boxes are assembled together with pillar and eye nuts before being placed into the inner receptacle, and in other cases, they are first conveyed into the inner receptacle and assembled together with pillars and nuts. Also, to unload pellet storage boxes from the inner receptacle, one of two procedures can be adopted: either first unload and then disassemble outside the inner receptacle or first disassemble inside the inner receptacle and then unload. The cover for the pellet storage box assembly can be attached to the assembly before or after the storing procedure.
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Two configurations can be selectively adopted for the pellet storage box assembly depending on the type of the pellet storage box: assembly A consisting of twelve (12) pellet storage boxes which can store up to 11 kg of UO2 per box and assembly B consisting of five (5) pellet storage boxes which can store up to 20 kg of UO2 per box. An assembly A has a maximum capacity of 132 kg of UO2 and an assembly B has a maximum capacity of 100 kg of UO2.
(1) Major nuclides and their radioactivities 232U 234U 235U 236U 238U 99Tc Total Radioactivities 1.34x108 2.70x1010 1.87x109 1.40x108 8.26x109 1.46x106 3.75x1010 (Bq)
(2) Physical conditions of package Pellets of uranium oxides (or pellets of uranium oxides mixed with gadolinium) are cylindrical ceramic solids of uranium oxides (or uranium oxides mixed with gadolinium) which are prepared by press-forming and sintering powder of uranium oxides (or uranium oxides mixed with gadolinium).
These pellets are lined up in neat arrangements on stainless steel corrugated plates in the stainless steel pellet storage box. Such pellets on corrugated plates are piled on each other in the box. Spacers of an organic polymeric material (neoprene rubber or urethane foam) are inserted between corrugated plates as required to minimize the adverse effect of vibration during transport. Pellet storage boxes are sometimes sealed in a plastic (polyethylene) bag for reasons of operation specific to the local site. In such cases, plastic bags are welded by means of a sealer or are protected with pieces of polyvinyl chloride adhesive tape. Fig. I-8 shows a general view of a pellet storage box.
To construct an assembly, pellet storage boxes are stacked alternately with partitions on the lowermost partition. These partitions are penetrated by six pillars. The stack of pellet storage boxes is fixed with nuts at the threaded top of the pillars. Positioning blocks of neoprene rubber are fixed with supports for positioning blocks on all the partitions except for the uppermost one.
Spacers of an organic polymeric material (neoprene rubber or urethane foam) are inserted between corrugated plates as required before constructing a pellet storage box assembly. Spacer blocks of neoprene rubber are attached to the bottom surfaces of all the partitions in the assembly B except for the lowermost one. Fig. I-9 shows a general view of a pellet storage box assembly.
The pellet storage box assembly is made of stainless steel except for the central partition and a few rubber parts. The central partition is constructed with boronic stainless steel plates. The central partition for assembly A consists of a 3-mm thick boronic stainless steel plate and that for assembly B consists of four 3-mm thick laminated boronic stainless steel plates. All the boronic stainless steel plates are of ASTMA887-89, 304B4 grade B. The boron concentration is within the range 1.0 to 1.24 weight percent. The partitions are spaced at a constant definite distance from each other by fixing blocks provided at the locations where the pillars penetrate.
Fig. I-10 and Fig. I-11 show the structure of pellet storage box assembly A and that of pellet storage box assembly B, respectively.
As integral parts of the packaging, eye nut holders for storing eye nuts for lifting pellet storage box assembly are attached to the top surface of the uppermost partition.
(3) Chemical properties Pellets of uranium oxides and pellets of uranium oxides mixed with gadolinium are chemically stable. They do not react with other materials contained in the packaging and do not provoke chemical reactions in such materials. They will not present risks of corrosion. If these pellets I-7
come into contact with other materials in the packaging, no electric potential differences will occur and thus will not cause electro-chemical reactions in any materials.
Stainless steel, boronic stainless steel and neoprene rubber have chemically stable properties and do not react with each other in the packaging. These materials also will not give rise to corrosion problems. If these materials come into contact with other materials, no electric potential differences will occur and thus will not cause electro-chemical reactions in any materials.
Organic polymeric materials (polyethylene, polyvinyl chloride and urethane) also are chemically stable. They do not react with each other in the packaging and do not provoke chemical reactions. Thus, they will not present risks of corrosion. If these pellets come into contact with such materials, no electric potential differences will occur and thus there will be no risk of electro-chemical reactions in any materials.
(4) Densities
- Pellet: 8 to 11 g/cm3
- Stainless steel: 7.9 g/cm3
- Boronic stainless steel: 7.8 g/cm3
- Neoprene rubber (chloroprene rubber): 1.15 to 1.25 g/cm3.
(5) Containment (closure) for contents The kinds of pellets to be contained in the packaging are ceramic solids prepared by press-forming and sintering powder of uranium oxides. Therefore, they do not disperse in the surrounding atmosphere like powder. The pellet storage box and the pellet storage box assembly are constructed without gaps between materials and between the interior and the exterior of the assembly which contains the nuclear fuel in sealed conditions. The packaging comprises no special materials or devices (seal or sealant) designed for ensuring liquid or gas leaktightness. The required containment or closure is guaranteed by the containment boundary formed by the inner receptacle, which can be retrieved from the outer receptacle without being dismantled.
(6) Maximum quantity of decay heat The packaging is designed to contain unirradiated pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium. The quantity of decay heat of these contents is negligible.
(7) Maximum pressure in the containment system The packaging is loaded with the designed contents at normal or ambient temperatures and under normal pressures. Therefore, the containment system established in the packaging is not pressurized.
(8) Limitations on content loading i) Enrichment It must be equal to or lower than 5.0 weight percent of the contents.
ii) Maximum storage
- When two pellet storage box assemblies A are installed: 264 kg of UO2
- When two pellet storage box B assemblies are installed: 200 kg of UO2.
Note: Assembly A (or B) is not mixed with assembly B (or A) in one packaging.
iii) Kinds of enriched uranium Kinds of enriched uranium (other than regenerated enriched uranium) which meet the requirements of the American Society for Testing and Materials standard ASTM C996-04 ECGU:
232U 0.0001 µg/gU 234U 10x103 µg/g235U 236U 250 µg/gU I-8
99Tc 0.01 µg/gU Note: When the condition 236U < 125 µg/gU is present, these criteria do not apply to 232U and 99Tc.
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Table I-1: Major Materials for the Packaging Components (1/2)
Division Components Material(s) Applicable Standard(s) Dimensions (mm) Remarks Outer plate Stainless steel JIS G 4304 or JIS G 4305 t 3 and t 2 Inner plate Stainless steel Ditto t2 Frame Stainless steel Ditto t5 Flange Stainless steel Ditto t 10 Lifting attachment Stainless steel Ditto t 10 Lid Anti-interference spacer Neoprene rubber t2 (chloroprene rubber)
Fire-resistant rubber Ethylene propylene rubber t3 Manufacturers specifications Shock absorber Aluminum honeycomb t 25.1 and t 35.1 Manufacturers specifications Insulator Ceramic fiber t 125 (as installed)
Outer Receptacle Outer plate Stainless steel JIS G 4304 or JIS G 4305 t3 Inner plate Stainless steel Ditto t2 JIS G 4317, JIS G 4304 or t 5 and Frame Stainless steel I - 10 JIS G 4305 L 50x50xt 5 Flange Stainless steel JIS G 4304 or JIS G 4305 t 10 Body of Receptacle Flange Spacer Silicone rubber t5 JIS G 3459, JIS G 3446, Protective square pipe Stainless steel 40xt 4 JIS G 4304 or JIS G 4305 Leg Stainless steel Ditto 125xt 4 Skid Urethane rubber t 10 Rod bolt Chrome molybdenum steel JIS G 4052 M 16 JIS G 4303, JIS G 4308, Nut Stainless steel M 16 JIS G 4315 or JIS G 4318 Insulator Ceramic fiber t 100 (as installed) Manufacturers specifications Shock absorber Aluminum honeycomb t 25.1 and t 35.1 Manufacturers specifications
Table I-1: Major Materials for the Packaging Components (2/2)
Division Components Material(s) Applicable Standard(s) Dimensions (mm) Remarks Guide Urethane rubber w 75 Commonly referred to as nylon Outer Receptacle Guide end MC nylon w 75 Body 6 Neoprene rubber Anti-vibration rubber t8 Manufacturers specifications (chloroprene rubber)
Casing Stainless steel JIS G 4303 31.5 Fusible Seat Stainless steel Ditto 40 plug Fusible material Solder JIS Z 3282 Lid plate Stainless steel JIS G 4304 or JIS G 4305 t 10 Lid bar (lifting Stainless steel Ditto t 15 Lid attachment)
Anti-interference Neoprene rubber t 10 I - 11 spacer (chloroprene rubber)
Lateral plate, bottom Inner Receptacle Stainless steel JIS G 4304 or JIS G 4305 t 6 and t 8 plate Flange Stainless steel Ditto t 12 Flange Spacer Silicone rubber t3 O-ring Silicone rubber 10 Body Rod bolt Chrome molybdenum steel JIS G 4052 M 16 Type 304B4 Grade B Neutron absorber Boronic stainless steel ASTM A887-89 t3 Boron concentration 1wt Anti-interference Neoprene rubber t3 spacer (chloroprene rubber)
Lifting point Lid of Outer Receptacle Fusible plug Flange Lid of Inner Receptacle Channel Pellet storage box assembly Rod bolt for outer receptacle Body of Outer Receptacle Rod bolt for inner receptacle Flange spacer Aluminum honeycomb element Body of Inner Assembly cover Receptacle Inner plate Outer plate Insulator Leg Fork guard Fig. I-1: General View of Type GP-01 Package I - 12
Anti-vibration rubber Guide Flange spacer Positioning pin View From Above Bolt seat Positioning pin Flange spacer Inner plate Flange Outer plate Guide Insulator Protective square pipe Aluminum honeycomb element Frame Anti-vibration rubber Fork guard Leg Vertical Section Skid Fig. I-2: Structure of Body of Outer Receptacle I - 13
Lifting attachment/point Fusible plug Water drainage hole View From Above Frame Outer plate Inner plate Channel Flange Fire-resisting rubber Insulator Vertical Section Aluminum honeycomb element Anti-interference spacer Fig. I-3: Structure of Lid of Outer Receptacle I - 14
Neutron absorber fixing block O-ring Neutron absorber Neutron absorber Anti-interference spacer Flange spacer Neutron absorber Positioning pin View From Above O-ring Flange spacer Bolt seat Anti-interference spacer Flange Guide Anti-interference spacer Neutron absorber Neutron absorber Vertical Section Fig. I-4: Structure of Body of Inner Receptacle I - 15
Lid bar (lifting point)
Positioning hole View From Above Lid bar (lifting point)
Vertical Section Anti-interference spacer Fig. I-5: Structure of Lid of Inner Receptacle I - 16
Neutron absorber Neutron absorber Neutron absorber Neutron absorber Neutron absorber fixing block Neutron absorber fixing block Fig. I-6: Positions of Neutron Absorbers Fusible zone (solder)
Main body Base View From Above Vertical Section Fig. I-7: Structure of Fusible Plug I - 17
Lid of pellet storage box Pellets Corrugated plate Pellet storage box Fig. I-8: General View of Pellet Storage Box (example)
Assembly cover handle Uppermost Uppermost partition Pillar Nut Partition (neutron absorber)
Positioning block holder Assembly cover Fig. I-9: General View of Pellet Storage Box Assembly (example)
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Positioning block holder Positioning block Pillar Pillar Nut Uppermost partition Positioning block holder Fixing block PartitionNeutron absorber Lowermost partition Fig. I-10: Structure of Pellet Storage Box Assembly (A)
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Positioning block holder Positioning block Pillar Pillar Nut Uppermost partition Positioning block holder Fixing block Positioning block Spacer Partition (neutron absorber)
Lowermost partition Fig. I-11: Structure of Pellet Storage Box Assembly (B)
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CHAPTER II - Safety Analysis of Nuclear Fuel Package This chapter shows that the design of package meets the applicable technical standards of Type A package as defined in the the NRA Ordinance on off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: Order of the Prime Ministers Office No.57 of December 28, 1978 (referred to Regulation) and in the the Notification on Technical Details for Off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: The Public Notice of the Science and Technology Agency No.5, an extra of November 28, 1990 (referred to Public Notice).
II-A. Structural Analysis A.1. Structural Designing A.1.1. General Fig. I-1 shows a general view of the package configured with a type GP-01 transport packaging.
The packaging is designed to contain and transport unirradiated uranium oxides (or uranium oxides with gadolinium) prepared in the form of pellets. The packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without being dismantled. The inner receptacle is designed to contain two pellet storage box assemblies which contain pellets of uranium oxides. Stainless steel is used for the major structural elements of the model of packaging, including various plates and rods.
The outer receptacle has a double structure composed of inner plates and outer plates. The voids between the inner plates and the outer plates are filled with blocks of a heat insulating material (ceramic fiber) to ensure heat resistance. A fusible plug is installed in the center of each of the outer faces of the outer receptacle. These fusible plugs are capable of preventing the inner pressure between the inner receptacle and the outer receptacle from rising at high temperatures.
The lid of the outer receptacle is firmly joined with the main body of the outer receptacle by means of twenty (20) rod bolts on the flange. Aluminum honeycomb elements are attached to the inner surfaces of the outer receptacle and the lid of the outer receptacle to attenuate any accidental shock against the inner receptacle. The top surface of the lid has six (6) recesses which mate with six legs of another outer receptacle when a package/packaging is placed in stack on another as required. These six recesses can be used for positioning the upper package/packaging. Four of the six recesses at the four corner of the receptacle have a hole and can serve as a set of lifting devices.
The inner receptacle has a caisson-shaped single structure. An O-ring is provided for sealing the receptacle on the flange surface. The lid of the inner receptacle is joined with the body of the inner receptacle by means of sixteen (16) rod bolts with nuts. Neutron absorbers consisting of boronic stainless steel plates are installed on the inner surfaces of the body of the inner receptacle.
Fig. I-6 shows the positions of these neutron absorbers installed.
A pellet storage box assembly consists of pellet storage boxes, six pillars, and partitions. Pellet storage boxes are stacked alternately with partitions. Two configurations can be selectively adopted II - A - 1
for the pellet storage box assembly depending on the type of the pellet storage box: assembly A and assembly B.
In some cases of loading, pellet storage boxes are assembled together with pillar and eye nuts before being loaded into the inner receptacle, and in others, they are first conveyed into the inner receptacle and assembled together with pillars and nuts. Also to unload pellet storage boxes from the inner receptacle, one of the two procedures can be adopted: either first unload and then disassemble outside the inner receptacle or first disassemble inside the inner receptacle and then unload. The cover for pellet storage box assembly can be attached to the assembly before or after storing process.
A.1.2. Applicable Design Standards This analysis was carried out to evaluate the structure of the Type A fissile package under the normal conditions and under the accident conditions as defined in the Regulations and in the Public Notice to prove that it meets the applicable technical standards.
Results of the analysis were examined and interpreted with the margin of safety to check that the package has a margin of safety of at least 1:
Margin of safety = Analytical criteria / Analytical value.
Table II-A-1 presents first the analysis items including reference drawings, materials used, design temperatures, and design loads on the portions concerned. Table II-A-1 also presents the analysis methods (equations and techniques used) and analytical criteria. The analytical criteria used include yield stress as tensile stress, yield stress multiplied by 1/3 as shear stress, and tensile stress or shear stress multiplied by 0.61 for the weld.
II - A - 2
Table II-A-1: Design Criteria for Structural Analysis (1/5)
Analysis Conditions Design Loads Analysis Methods Remark Analysis Items Reference Design Material Load s Drawings Temperatures Category Items Applied Equations and Elements Criteria Factor
- 1. Chemical and electrical Ambient No chemical reactions - - temperatures Corrosion - Reactivity Presence of reactivity reaction occurs.
(1) Chemical reactions
- - Ambient Corrosion - Potential Presence of electrical potential No electrical (2) Electrical reactions temperatures difference between different potential materials difference is present between different Routine Conditions of Transport II - A - 3 materials.
- 2. Low temperature strength (1) Structural elements
- SUS 304 -40°C Lowest - Low-temp. Performance deterioration -
temperature strength (2) Shock absorbers
- Aluminum -40°C Lowest - Low-temp. Performance deterioration -
honeycomb temperature strength (3) Spacers and O-ring
- Silicone rubber -40°C Lowest - Performance Performance deterioration -
temperature deterioration (4) Insulators
- Ceramic fiber -40°C Lowest - Performance Performance deterioration -
temperature deterioration (5) Rod bolts
- SCM 435 H -40°C Lowest - Low-temp. Performance deterioration -
temperature strength Any operational
- 3. Containment system Fig. I-4 - - - - Operational Fail-safe mechanism error does not error open the containment system.
- 4. Lifting devices (1) Outer receptacle, lifting Fig. II-A-4 SUS 304 Ambient Weight of package 3 Tensile stress AT=Fz/AA -
attachments, A-section temperatures Shear stress AX=Fx/AA -
Shear stress AY=Fy/AA -
Bending stress AB= Fy L/ZA -
Combined AC AT2 AB2 ATAB 3 AX2 3 AY2 y stress (2) Outer receptacle, lifting Fig. II-A-5 SUS 304 Ambient Weight of package 3 Tensile stress BT=Fx/AB -
attachments, temperatures Shear stress BZ=Fz/AB -
B-section Shear stress BY=Fy/AB -
BC BT 2
3 BZ 2
3 BY 2
Combined y stress (3) Outer receptacle, lifting Fig. II-A-6 SUS 304 Ambient Weight of package 3 Shear stress s= Fz/As 0.352y attachments, temperatures (=1/3 0.61) caisson-shaped zones, II - A - 4 welds
Table II-A-1: Design Criteria for Structural Analysis (2/5)
Analysis Conditions Design Loads Analysis Methods Remark Analysis Items Reference Design Materials Load s Drawings Temperatures Category Item Category Criteria Factor (4) Outer receptacle, welds Fig. II-A-7 SUS 304 Ambient Weight of package 3 Tensile stress =Fz/A 0.61y between lifting temperatures attachments and lid (5) Outer receptacle, rod Fig. I-1 SCM435H Ambient Weight of package 3 Tensile stress R=Fz/(nAR)+T/(KdAR) y bolts temperatures (6) Inner receptacle, lifting Fig. II-A-8 SUS 304 Ambient Weight of package 3 Tensile stress AT=Fz/AA -
attachments, temperatures Shear stress AX=Fx/AA -
A-section Shear stress AY=Fy/AA -
Routine Conditions of Transport Bending stress AB= Fy L/ZA -
II - A - 5 Combined AC AT2 AB2 ATAB 3 AX2 3 AY2 y stress (7) Inner receptackle, Fig. II-A-9 SUS 304 Ambient Weight of package 3 Tensile stress BT=Fy/AB -
lifting attachments, temperatures Shear stress BZ=Fz/AB -
B-section Shear stress BX=Fx/AB -
BC BT 2
3 BZ 2
3 BX 2
Combined y stress (8) Inner receptacle, lifting Fig. II-A-10 SUS 304 Ambient Weight of package 3 Tensile stress T=Fz/A -
attachments, welds temperatures Shear stress X=Fx/A -
Bending stress B= Fy L/Z -
C T2 B 2
T B 3 X 2
Combined 0.61y stress (9) Inner receptacle, rod Fig. I-1 SCM435H Ambient Weight of package 3 Tensile stress R=Fz/(nAR)+T/(KdAR) y bolts temperatures
- 5. Tie-down system - - - - - - - - N/A
Table II-A-1: Design Criteria for Structural Analysis (3/5)
Analysis Conditions Design Loads Analysis Methods Remark Annlysis Items Reference Design Materials Load Applied Equations and s Drawings Temperatures Category Item Criteria Factor Elements 6Pressures (1) Inner receptacle - SUS 304 Ambient Inner pressure 1 Bending stress max=pa2/h2 y narrower lateral temperatures sides -
SUS 304 Ambient Inner pressure 1 Bending stress max=pa2/h2 y Routine Conditions of Transport (2) Inner receptacle - temperatures wider laterals sides
- SUS 304 Ambient Inner pressure 1 Bending stress max=pa2/h2 y (3) Inner receptacle temperatures bottom - SUS 304 Ambient temperatures Inner pressure 1 Bending stress max=pa2/h2 y II - A - 6 (4) Inner receptacle top surface SCM 435 H Ambient Inner pressure 1 Tensile stress R= F/(nAR)+T/(KdAR) y temperatures (5) Inner receptacle rod bolts 7Vibration - - - - - Vibration Crack and damage Damage to package Damage to contents
Table II-A-1: Design Criteria for Structural Analysis (4/5)
Analysis Conditions Design Load Analysis Methods Remark Annlysis Items Reference Design Materials Load Applied Equations and s Drawings Temperatures Category Item Criteria Factor Elements 1Pressures (1) Inner receptacle, - SUS 304 59°C Inner pressure 1 Bending stress max=pa2/h2 y Narrower lateral sides (2) Inner receptacle, wider - SUS 304 59°C Inner pressure 1 Bending stress max=pa2/h2 y laterial sides (3) Inner receptacle, bottom - SUS 304 59°C Inner pressure 1 Bending stress max=pa2/h2 y surface (4) Inner receptacle, top - SUS 304 59°C Inner pressure 1 Bending stress max=pa2/h2 y surface Normal Conditions of Transport (5) Inner receptacle, rod - SCM 435 H 59°C Inner pressure 1 Tensile stress R= F/(nAR)+T/(KdAR) y bolts II - A - 7 2Water spray - - Ambient Water spray - Infiltration of - Deterioration temperatures water of quality Internal water in-leakage 3Free drop - SUS 304 Ambient Drop from a 1 Deformation Prototype packaging test Deformation, Horiz. lid facing downward temperatures height of 1.2 fracture Horiz. narr. side facing m Leakage of downward contents Corner facing downward 4Stacking Fig. II-A-11 SUS 304 Ambient Weight of 5 Buckling load c Buckling load temperatures package W A c 1 2 2
4 n E 5Penetration - SUS 304 Ambient Drop of a 1 Penetration Prototype packaging test Penetration temperatures cylindrical rod from a height of 1 m
Table II-A-1: Design Criteria for Structural Analysis (5/5)
Analysis Conditions Design Load Analysis Methods Remark Annlysis Items Reference Materials Temperatures Load Applied Equations and s Drawings Category Item Criteria Factor Elements
- 1. Drop I - SUS 304 Ambient Drop from a 1 Deformati Prototype packaging test Deformation, Horiz. lid facing downward temperature height of 9 m on fracture Horiz. narrower side facing s Contents downward affected Horiz.wider side facing downward Accident Conditions of Transport (Fissile Package)
Inclined narrower side Corner facing downward
- 2. Drop II - SUS 304 Ambient Drop from a 1 Deformati Prototype packaging test Deformation, Horiz. lid facing downward temperature height of 1 m on fracture II - A - 8 Horiz. near leg onto p. bar s onto the p. bar Contents Incl. wider side lifting affected attachment onto p. bar Incl. wider side center Incl. wider side flange 3Thermal test - - 800°C - - - Prototype packaging test -
Analytical model 4Water immersion test - - - - - - - - Water immers ion is taken into account in criticali ty analysi s.
A.2. Weights and Center of Gravity Table II-A-2 shows the weights of the package and major components of the package. Fig. II-A-1 shows the location of the center of gravity of the package.
Table II-A-2: Weight of Package (maximum)
(Unit: kg)
Package 730 Outer receptacle body (393)
Outer receptacle lid (147)
Inner receptacle body (150)
Inner receptacle lid (40)
Contents (pellet storage box 570 assemblies)
Gross Weight 1300 Our analytical calculation assumes that the maximum weight of the package weighs 1300 kg.
Fig. II-A-1: Center of Gravity of the Package II - A - 9
A.3. Mechanical Properties of Materials of Packaging Table II-A-3 shows the mechanical properties of the major materials which comprise the packaging II - A - 10
Table II-A-3: Mechanical Properties of Major Structural Materials Elongat Youngs Density Yield Stress Tensile Strength ion Modulus Material Category (kg/m3) (MPa) (MPa)
(%) (MPa) 20°C 20°C 75°C 170°C 20 °C 75°C 170°C 20°C 20°C Plates SUS 304 7930 205 183 151 520 466 414 40 1.93 105 SUS 304TP 7930 205 183 151 520 466 414 35 1.93 105 Pipes Stainless steel SUS 304 7930 205 183 151 520 466 414 40 1.93 105 Rods SUS 304 7930 205 183 151 520 466 414 40 1.93 105 Angles SUS 304 7930 205 183 151 520 466 414 40 1.93 105 Chrome-molyb II - A - 11 Rods SCM435H 7830 785 712 643 930 847 847 15 2.05 105 denum steel
A.4. Requirements for Package A.4.1. Chemical and Electrical Reactions Table II-A-4 lists the kinds of packaging materials which stay in contact with each other or with parts of the contents. None of the contact combinations for these materials produce hazardous chemical or electrical reactions.
Table II-A-4: Contact Combinations for Different Kinds of Materials Contact Combination for Materials Relevant Elements of Packaging Stainless steel + Chrome molybdenum steel Outer receptacle + Rod bolt Inner receptacle + Rod bolt Stainless steel + Ceramic fiber Outer receptacle + Insulator Stainless steel + Aluminum Outer receptacle + Shock absorber Inner receptacle+ Shock absorber Stainless steel + Urethane rubber Outer receptacle + Skid Outer receptacle + Guide Stainless steel + Silicone rubber Outer receptacle + Flange spacer Inner receptacle + Flange spacer/O-ring Stainless steel + Neoprene rubber Inner receptacle + Anti-interference Spacer Inner receptacle + Antivibration rubber Stainless steel + Ethylene propylene rubber Outer receptacle + Fire resisting rubber Stainless steel + Solder Fusible plug casing + Fusible plug fusible zone Stainless steel + Boronic stainless steel Inner receptacle + Neutron absorber Boronic stainless steel + Neoprene rubber Neutron absorber + Anti-interference Spacer Aluminum + Neoprene rubber Shock absorber + Antivibration rubber Shock absorber + Anti-interference Spacer Urethane rubber + MC nylon Guide main part + Guide tip MC nylon + Stainless steel Inner receptacle + Guide tip II - A - 12
A.4.2. Low-temperature Strength Metallic materials for the packaging include austenite stainless (equivalent to SUS 304), chrome molybdenum steel (equivalent to SCM 435) and aluminum alloy. All these materials do not lose their strength or their capabilities in an environment kept at -40°C (see Appendix 2 to Chapter II-A).
Neoprene rubber and silicone rubber are the materials used for the O-ring and spacers of the packaging. The neoprene rubber has brittle temperatures of around -55 to -35°C. This material is not taken into account in our structural evaluations and its embrittlement is regarded non-relevant to the structural risks of the packaging. The silicone rubber used to form the required containment boundary has a brittle temperature of
-50°C or even lower and will not lose part of its capabilities at low temperatures.
The insulator for the packaging is made of a ceramic fiber. The insulator, not designed for application in an environment at -40°C, will not give birth to any issues relative to deterioration of insulating capability at low temperatures. Besides, this material will not deteriorate at -40°C.
A.4.3. Containment System As containment system is regarded the inner receptacle of the packaging. The inner receptacle consists of a body and a lid. An O-ring is installed along the groove on the inner receptacle flange. Sixteen (16) rod bolts are tightened with nuts and spring lock washers to press the lid of the inner receptacle against the O-ring on the body of the inner receptacle, thus ensuring the required containment in the inner receptacle. These bolts will not loosen during transport.
The inner receptacle is installed in the outer receptacle. The lid of the outer receptacle is firmly joined with the body of the outer receptacle by means of twenty (20) rod bolts on the flange. These bolts will not loosen during transport.
Common tools such as wrenches are required to loosen and remove the tightened rod bolts. A crane is required to open the lid of the outer receptacle which weighs more than 100 kg. To transport the package, the lid of the outer receptacle should be tied down with suitable means on the transport vehicle (truck, transport container, etc.) to prevent the package from rattling moving up and down on the vehicle.
Thus, once the package is correctly prepared, the containment system cannot be opened erroneously without express intention to do so.
II - A - 13
A.4.4. Lifting Devices Lifting devices are the lifting attachments on the outer receptacle shown in Fig. I-3 and the lifting attachments on the inner receptacle shown in Fig. I-5. All these lifting attachments are made of stainless steel. Those of the outer receptacle are welded on the frames and those of the inner receptacle on the lid. The lifting devices have a structure designed to support a load three times the overall weight of package. They will endure jerky lifting operation of the package.
The lifting attachments on the inner and outer receptacle were evaluated to check that stresses which may occur in the thick portions of the plates, welds and rod bolts will remain in the specified ranges.
The lifting operation of the inner and outer receptacle performed using four steel wires of 1-meter or longer as shown in Fig. II-A-2 and Fig. II-A-3. Stresses generated on the lifting attachments as lifting devices were determined.
At the lifting wire angles shown these figures, the load (stress) on one of the lifting attachments is determined as follows:
3 Fz WG 4
Fx Fz / tan(90 x )
Fy Fz / tan(90 y )
where Fz: vertical component of the load acting on the lifting attachment [N]
Fx: horizontal longitudinal component of the load acting on the attachment [N]
Fy: horizontal transversal component of the load acting on the lifting attachment [N]
W: gross weight of the package Outer receptacle: 1300 kg Inner receptacle: 760 kg G: gravitational acceleration = 9.80665 m/s
- angle formed by the wire and the vertical line on the longitudinal plane Outer receptacle: 32.3° Inner receptacle: 19.8°
- angle formed by the wire and the vertical line on the transversal plane Outer receptacle: 28.0° Inner receptacle: 8.5°.
Thus, the load components in the outer receptacle are:
Fz = 9562 [N]
Fx = 6039 [N]
Fy = 5084 [N]
And the load components in the inner receptacle are:
Fz = 5590 [N]
Fx = 2010 [N]
Fy = 840 [N].
II - A - 14
Fz Fz F F II - A - 15 Fig. II-A-2: Lifting Operation on Outer Receptacle
Fz Fz F
II - A - 16 F
Fig. II-A-3: Lifting Operation on Inner Receptacle
A.4.4.1. Stresses on A-section of the outer receptacle lifting attachment The lifting attachment is a box-shaped part composed of five stainless steel plates welded with each other. While the packaging is lifted, the overall load is distributed to these five plates. In our analysis, stresses produced during lifting operation are determined conservatively on the assumption that the entire load is concentrated on one of the plates.
A-section (see Fig. II-A-4) is exposed to a tensile stress resulting from the vertical load component, a shear stress resulting from the longitudinal load on cross-section and a bending stress resulting from the transversal load on cross-section.
A-section Fig. II-A-4: A-section of the outer receptacle lifting attachment (1) Vertical tensile stress The tensile stress is represented by:
Fz AT AA where AT: tensile stress generated on A-section [MPa]
F: vertical component of the load acting on the outer receptacle lifting attachment =
9562 [N]
AA: area of A-section = 1470 [mm2]
- stress concentration factor (for steel strip having a round hole) = 2.6.
These values are assigned:
9562 AT 2.6 17.0 [MPa]
1470 II - A - 17
(2) Horizontal longitudinal shear stress This shear stress is represented as follows:
Fx AX AA where AX: horizontal longitudinal shear stress on A-section [MPa]
F: longitudinal component of the load acting on the outer receptacle lifting attachment =
6039 [N]
AA: area of A-section = 1470 [mm2].
These values are assigned:
6039
= 1470
= 4.2 [MPa]
(3) Horizontal transversal shear stress This shear stress is represented as follows:
Fy AY AA where AY: horizontal transversal shear stress generated on A-section [MPa]
F: transversal component of the load acting on the outer receptacle lifting attachment =
5084 [N]
AA: area of A-section = 1470 [mm2].
These values are assigned:
5084 AY 3.5 [MPa]
1470 (4) Horizontal transversal bending stress This bending stress is represented as follows:
Fy L AB ZA where AB: bending stress generated on A-section [MPa]
F: transversal component of the load acting on the outer receptacle lifting attachment =
5084 [N]
ZA: section modulus of A-section [mm2]
ZA(147 102)/62450 [mm2]
L: distance from A-section to the point of load application = 31 [mm].
These values are assigned:
5084 31 AB 64.4 [MPa]
2450 (5) Combined stress The combined stress while a vertical stress and a shear stress simultaneously occur is represented as follows:
AC AT 2 AB 2 AT AB 3 AX 2 3 AY 2 where AC: combined stress generated on A-section [MPa]
II - A - 18
AT: tensile stress generated on A-section = 17.0 [MPa]
AB: bending stress generated on A-section = 64.4 [MPa]
AX: horizontal longitudinal shear stress generated on A-section = 4.2 [MPa]
AY: horizontal transversal shear stress generated on A-section = 3.5 [MPa].
These values are assigned:
= 17. 02 + 64. 42 17.0 x 64.4 + 3 x 4. 22 + 3 x 3. 52 = 58.6 [MPa]
Thus, the overall stress generated on A-section of the outer receptacle lifting attachment is lower than 205 MPa, the allowable tensile stress for the stainless steel. The margin of safety is:
205 Margin of safety = = 3.4 58.6 A.4.4.2. Stresses on B-section of the outer receptacle lifting attachment The lifting attachment is a box-shaped part composed of five stainless steel plates welded with each other. While the packaging is lifted, the overall load is distributed to these five plates. In our analysis, stresses produced during lifting operation are determined conservatively on the assumption that the entire load is concentrated on one of the plates.
B-section (see Fig. II-A-5) is exposed to a tensile stress resulting from the horizontal longitudinal load on cross-section, a shear stress resulting from the vertical load on cross-section and a shear stress resulting from the transversal load on cross-section.
B-section Fig. II-A-5: B-section of the outer receptacle Lifting Attachment (1) Horizontal longitudinal tensile stress This tensile stress is represented as follows:
Fx BT AB II - A - 19
where BT: tensile stress generated on B-section [MPa]
F: horizontal longitudinal component of the load generated on outer receptacle lifting attachment = 6039 [N]
AB: area of B-section = 320 [mm2]
- stress concentration factor (for steel strip having a round hole) = 2.2.
These values are assigned:
6039 BT 2.2 41.6 [MPa]
320 (2) Vertical shear stress This shear stress is represented as follows:
Fz BZ AB where BZ: vertical shear stress generated on B-section [MPa]
F: vertical component of the load generated on the outer receptacle lifting attachment =
9562 [N]
AB area of B-section = 160 [mm2] (only the round-hole side is taken into account).
These values are assigned:
9562 BZ 59.8 [MPa]
160 (3) Horizontal transversal shear stress This shear stress is represented as follows:
Fy BY AB where BY: horizontal transversal shear stress generated on B-section [MPa]
F: transversal component of the load acting on outer receptacle lifting attachment =
5084 [N]
AB: area of B-section = 320 [mm2].
These values are assigned:
5084 BY 15.9 [MPa]
320 (4) Combined stress The combined stress while a vertical stress and a shear stress simultaneously occur is represented as follows:
BC BT 2 3 BZ 2 3 BY 2 where BC: combined stress produced on B-section [MPa]
BT: tensile stress produced on B-section = 41.6 [MPa]
BZ: horizontal longitudinal shear stress produced on B-section = 59.8 [MPa]
BY: horizontal transversal shear stress produced on B-section = 15.9 [MPa].
These values are assigned:
II - A - 20
BC 41.6 2 3 59.8 2 3 15.9 2 115.0 [MPa]
Thus, the overall stress generated on B-section of the outer receptacle lifting attachment is lower than 205 MPa, the allowable tensile stress for the stainless steel. The margin of safety is:
205 Margin of safety 1.7 115.0 A.4.4.3. Stresses on welds of box-shaped attachment on outer receptacle lifting attachment The lifting attachment is a box-shaped attachment composed of five stainless steel plates welded with each other. This attachment is continuously welded on eight (8) mating points on the outer receptacle. In our analysis, stresses produced during lifting operation are determined conservatively on the assumption that the entire load is concentrated on the welds on both sides of the holed plate.
The welds indicated in Fig. II-A-6 are exposed to a shear stress resulting from the vertical load on cross-section.
Weld Fig. II-A-6: Lateral Welds of Box-shaped Attachment The shear stress is represented as follows:
Fz s
As where s: vertical shear stress generated on the section of the weld on the side [MPa]
F: vertical component of the load acting on the outer receptacle lifting attachment =
9562 [N]
II - A - 21
A: effective sectional area of the lateral weld = 233.3 [mm2] (throat thickness x weld length).
These value are assigned:
9562 s 41.0 [MPa]
233.3 Thus, the stress generated on the section of the weld on the box-shaped lifting attachment is lower than 72 MPa (0.61), value obtained by deducting the amount corresponding to a reduction in strength caused by fillet welding joint from the allowable shear stress, 118 MPa (=/3). The margin of safety is:
72 Margin of safety 1.7 41.0 A.4.4.4. Stresses on weld between lid frame and lid channel and outer receptacle lifting attachment The box-shaped attachment is joined by welding with the frame of the lid of the outer receptacle.
Our evaluation is carried out conservatively on the assumption that the entire load during lifting is concentrated on the weld between the lid frame/channel and the lifting attachment.
Fig. II-A-7 shows the weld on which a tensile stress is resulting from the vertical load on cross-section.
Weld Fig. II-A-7: Weld on Bottom of Box-shaped Lifting Attachment The tensile stress is represented as follows:
Fz L
AL where
- vertical tensile stress produced on the section of the weld on the bottom [MPa]
FZ: vertical component of the load acting on the weld on the bottom = 9562 [N]
II - A - 22
A: effective area of the weld on the bottom = 772.2 [mm2] (throat thickness x by weld length).
These values are assigned:
9562 L 12.4 [MPa]
772.2 Thus, the overall stress generated on the section of the weld between the lid frame/channel and the lifting attachment is lower than 125 MPa (0.61), value obtained by deducting the amount corresponding to a reduction in strength caused by fillet welding joint from the allowable tensile stress. The margin of safety is:
125 Margin of safety 10.0 12.4 A.4.4.5. Stresses on rod bolts during lifting Rod bolts shown in Fig. I-1 are used to join the body of the outer receptacle with the lid. In our analysis, stresses produced during lifting are determined on the assumption that stresses resulting from the gross weight (except for the lid) combined with the rod bolt tightening torque are generated on the rod bolts.
The tensile stress is represented as follows:
FZ T R
n AR K d AR where R: tensile stress generated on the section of the rod bolts [MPa]
FZ: vertical component of the load acting on the rod bolts = 33922 [N]
n: number of rod bolts = 20 AR: sectional area of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm].
These values are assigned:
33922 44130 R 186.5 [MPa]
20 157 0.1 16 157 Thus, the overall stress generated on the rod bolt is lower than the allowable tensile stress (785 MPa) for the chrome molybdenum steel. The margin of safety is:
785 Margin of safety 4.2 186.5 II - A - 23
A.4.4.6. Stresses on A-section of the outer receptacle lifting attachment The inner receptacle lid bar (see Fig. I-5), made of stainless steel, is welded on the lid of the inner receptacle. The lifting points are located at the inverted-U-shaped holes.
Fig. II-A-8 shows A-section on which a tensile stress resulting from the vertical load, a bending stress and a shear stress resulting from the longitudinal load on cross-section, and a shear stress resulting from the transversal load on cross-section are generated.
A-section Fig. II-A-8: A-section of the inner receptacle Lifting Attachment (1) Vertical tensile stress The vertical tensile stress is represented as follows:
Fz AT AA where AT: tensile stress generated on A-section [MPa]
F: vertical component of the load acting on the inner receptacle lifting attachment =
5590 [N]
AA: area of A-section = 810 [mm2]
- stress concentration factor (for steel strip having a round hole) = 2.35.
These values are assigned:
5590 AT 2.35 16.3 [MPa]
810 (2) Horizontal longitudinal shear stress This shear stress is represented as follows:
II - A - 24
Fx AX AA where AX: horizontal longitudinal shear stress generated on A-section [MPa]
F: longitudinal component of the load acting on the inner receptacle lifting attachment =
2010 [N]
AA: area of A-section = 810 [mm2].
These values are assigned:
2010 AX 2.5 [MPa]
810 (3) Horizontal transversal shear stress This shear stress is represented as follows:
Fy AY AA where AY: horizontal transversal shear stress on A-section [MPa]
F: transversal component of the load acting on the inner receptacle lifting attachment =
840 [N]
AA: area of A-section = 810 [mm2].
These values are assigned:
840 AY 1.1 [MPa]
810 (4) Horizontal longitudinal bending stress This bending stress is represented as follows:
Fx L AB ZA where AB: Bending stress generated on A-section [MPa]
F: longitudinal component of the load acting on the inner receptacle lifting attachment =
2010 [N]
ZA: section modulus of A-section [mm2]
ZA = (54 152)/6 = 2025 [mm2]
L: distance from A-section to the point of load application = 22 [mm].
These values are assigned:
2010 22 AB 21.9 [MPa]
2025 (5) Combined stress The combined stress (simultaneous occurrence of a vertical stress and a shear stress) is represented as follows:
AC AT 2 AB 2 AT AB 3 AX 2 3 AY 2 where AC: combined stress generated on A-section [MPa]
AT: tensile stress generated on A-section = 16.3 [MPa]
II - A - 25
AB: bending stress generated on A-section = 21.9 [MPa]
AX: horizontal longitudinal shear stress generated on A-section = 2.5 [MPa]
AY: horizontal transversal shear stress generated on A-section = 1.1 [MPa].
These values are assigned:
AC 16.3 2 21.9 2 16.3 21.9 3 2.5 2 3 1.12 20.3 [MPa]
Thus, the overall stress generated on A-section of the inner receptacle lifting attachment is the lower than 205 MPa, the allowable tensile stress for the stainless steel. The margin of safety is:
205 Margin of safety 10.0 20.3 A.4.4.7. Stresses on B-section of the inner receptacle lifting attachment The bar (see Fig. I-5), made of stainless steel, is welded on the lid of the inner receptacle. The lifting points are located at the inverted-U-shaped holes.
Fig. II-A-9 shows B-section on which a tensile stress resulting from the transversal load on cross-section, a shear stress resulting from the vertical load and a shear stress resulting from the longitudinal load on cross-section are generated.
B-section Fig. II-A-9: B-section of the inner receptacle Lifting Attachment (1) Horizontal transversal tensile stress Tensile stress is represented as follows:
Fy BT AB where BT: tensile stress generated on B-section [MPa]
II - A - 26
F: horizontal transversal component of the load acting on the inner receptacle lifting attachment = 840 [N]
AB: area of B-section = 120 [mm2]
- stress concentration factor (for steel strip having a round hole) = 2.1.
These values are assigned:
840 BT 2.1 14.7 [MPa]
120 (2) Vertical shear stress The vertical shear stress is represented as follows:
Fz BZ AB where BZ: vertical shear stress generated on B-section [MPa]
F: vertical component of the load acting on the inner receptacle lifting attachment =
5590 [N]
AB: area of B-section = 120 [mm2].
These values are assigned:
5590 BZ 46.6 [MPa]
120 (3) Horizontal longitudinal shear stress This shear stress is represented as follows:
Fx BX AB where BX: horizontal transversal shear stress generated on B-section [MPa]
F: longitudinal component of the load acting on the inner receptacle lifting attachment =
2010 [N]
AB: area of B-section = 120 [mm2]
These values are assigned:
2010 BY 16.8 [MPa]
120 (4) Combined stress The combined stress (simultaneous occurrence of a vertical stress and a shear stress) is represented as follows:
BC BT 2 3 BZ 2 3 BX 2 where BC: combined stress generated on B-section [MPa]
BT: tensile stress generated on B-section = 14.7 [MPa]
BZ: horizontal vertical shear stress generated on B-section = 46.6 [MPa]
BX: horizontal longitudinal shear stress generated on B-section = 16.8 [MPa].
These values are assigned:
BC 14.7 2 3 46.6 2 3 16.8 2 87.1 [MPa]
II - A - 27
Thus, the overall stress generated on B-section of the inner receptacle lifting attachment is lower than 205 MPa, the allowable tensile stress for the stainless steel. The margin of safety is:
205 Margin of safety 2.3 87.1 A.4.4.8. Stresses on welds of the inner receptacle lifting attachment The inner receptacle lid bar (see Fig. I-5), made of stainless steel, is welded on the lid of the inner receptacle all around each of its bottom faces.
Fig. II-A-10 shows the welded faces of the inner receptacle lid bar on which a tensile stress resulting from the vertical load, a bending stress and a shear stress resulting from the longitudinal load on cross-section occur.
Weld Fig. II-A-10: Welds of the inner receptacle Lifting Attachment (1) Vertical tensile stress This tensile stress is represented as follows:
Fz T
A where T: vertical shear stress generated on the weld of the inner receptacle lid bar [MPa]
FZ: vertical component of the load acting on the weld of the inner receptacle lid bar =
11180 [N]
(As two inner receptacle lid bars are provided on an inner receptacle, the vertical load component per bar is a half (11180 N) of the entire load. As four lifting points are provided, the load component for one lifting point is a quarter (5590 N) of the entire load.)
A: total effective sectional area of the inner receptacle lid bar = 1492 [mm2] (throat thickness x weld length)
II - A - 28
These values are assigned:
11180 T 7.5 [MPa]
1492 (2) Horizontal longitudinal shear stress This shear stress is represented as follows:
Fx X
AX where X: horizontal longitudinal shear stress generated on the weld of the inner receptacle lid bar [MPa]
F: longitudinal component of the load acting on the weld of the inner receptacle lid bar
= 4020 [N]
(As two inner receptacle lid bars are provided on an inner receptacle, the longitudinal component per bar is a half (4020 N) of the entire load. As four lifting points are provided, the load component for one lifting point is a quarter (2010 N) of the entire load.)
AX: effective sectional area of welded portions which are at right angles to the longitudinal line of the receptacle = 962 [mm2]
(To be conservative, the welded portions which are at right angles to the transversal line of the receptacle are not taken into account.)
These values are assigned:
4020 X 4.2 [MPa]
962 (3) Horizontal longitudinal bending stress This bending stress is represented as follows:
Fx L B
Z where B: bending stress generated on the inner receptacle lid bar [MPa]
F: transversal component of the load acting on the inner receptacle lid bar = 4020 [N]
(As two inner receptacle lid bars are provided on an inner receptacle, the longitudinal component per bar is a half (4020 N) of the entire load. As four lifting points are provided, the load component for one lifting point is a quarter (2010 N) of the entire load.)
Z: section modulus of the inner receptacle lid bar [mm2]
ZA = (136 7.12)/6 = 1143 [mm2]
L: distance from welds to the point of load application = 26 [mm]
These values are assigned:
4020 26 B 91.5 [MPa]
1143 (4) Combined stress The combined stress (combination of a vertical stress and a shear stress) is represented as follows:
C T 2 B 2 T B 3 X 2 where II - A - 29
C: combined stress generated on the weld of the inner receptacle lid bar [MPa]
T: tensile stress generated on the weld of the inner receptacle lid bar = 7.5 [MPa]
B: bending stress generated on the weld of the inner receptacle lid bar = 91.5 [MPa]
X: horizontal longitudinal shear stress generated on the weld of the inner receptacle lid bar = 4.2 [MPa]
These values are assigned:
C 7.5 2 91.5 2 7.5 91.5 3 4.2 2 88.3 [MPa]
Thus, the overall stress generated on the weld of the inner receptacle lid bar is lower than 125 MPa (0.61), the allowable tensile stress for the stainless steel which takes into account a reduction in strength caused by fillet welding joint. The margin of safety is:
125 Margin of safety 1.4 88.3 A.4.4.9. Stresses on rod bolts during lifting Rod bolts shown in Fig. I-1 are used to join the body of the outer receptacle with the lid. In our analysis, stresses produced during lifting are determined on the assumption that stresses resulting from the gross weight (except for the lid) combined with the rod bolt tightening torque are generated on the rod bolts.
The tensile stress is represented as follows:
FZ T R
n AR K d AR where R: tensile stress generated on the section of the rod bolt [MPa]
FZ: vertical component of the load acting on the rod bolt = 22360 [N]
n: number of rod bolts = 16 AR: sectional area of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm]
These values are assigned:
22360 44130 R 184.6 [MPa]
16 157 0.1 16 157 Thus, the overall stress generated on the rod bolt is lower than the allowable tensile stress (785 MPa) for the chrome molybdenum steel. The margin of safety is:
785 Margin of safety 4.2 184.6 A.4.4.10 Evaluation of Repetitive Stress due to Lifting The stress on the stainless steel lifting part was evaluated in A.4.4.1 to A.4.4.8, and results showed that maximum stress is 115.0 MPa and the stress amplitude is 57.5 MPa from 115.0÷2.
The planned period of use for the packaging is 80 years, and the total number of transports is II - A - 30
160 times during the period of use. The number of times the packaging is scheduled to be lifted is 10 times per transport and 20 times per year other than transport, for a total of 3,200 times (160x10 + 80x20) throughout the period of use. In the evaluation of repetitive stress, as a more conservative condition than the planned use, the number of transports over the period of use is assumed to be twice as many as planned (160x2 = 320 times)and the number of times lifted per year other than transport is assumed to be twice as many as planned (20x2 =
40 times), for a total of 6,400 times (320x10 + 80x40) of stress generation considered.
According to the fatigue curve of stainless steel shown in (II)-A Figure 11, fatigue failure does not occur even if the stress amplitude is 100 MPa or less and repetitive stress is generated more than 107 times in an environment from room temperature to 700°C.
Furthermore, the results of evaluating chrome molybdenum steel rod bolts in A.4.4.9 showed that stress is 184.6 MPa and the stress amplitude is 92.3 MPa from 184.6÷2. In evaluation of repetitive stress, the number of occurrences of stress to be considered is 6,400, the same as for stainless steel. According to the fatigue curve of chrome molybdenum stainless steel shown in (II)-A Figure 12, fatigue failure does not occur even if the stress amplitude is 206 MPa (3.0x104 psi) or less and repetitive stress is generated more than 106 times in an environment from room temperature to 371°C (700°F).
Thus, fatigue failure due to repetitive stress caused by lifting does not occur.
II - A - 31
(II)-A Figure 11. Stainless Steel Fatigue Curve (Source) Handbook for stainless steels - 3rd Edition - Japan Stainless Steel Association (January 1995)
(II)-A Figure 12. Chrome Molybdenum Steel Fatigue Curve (Source) Tatsuo Oku, Toshihiko Kikuyama, Kiyoshi Fukaya, Tsuneo Kodaira, Mechanical Properties Data of 2-1/4 Cr-Mo Steel for the Experimental Very High Temperature Gas-Cooled Reactor (November 1978)
II - A - 32
A.4.5. Tie-down System To transport the package, the lid of the outer receptacle should be tied down with wires and other suitable common means and dedicated tie-down materials including spacers on the transport vehicle (truck, transport container, etc.) to prevent the package from rattling on the vehicle. The packaging is not equipped with any tie-down devices.
A.4.6. Pressure The package is evaluated for integrity in an environment where the ambient pressure drops to 60 kPa (absolute value). Since the contents is conducted indoors, the initial condition is 0°C. The temperature at the time of evaluation is 59°C, which is the average temperature inside inner receptacle under normal conditions. The pressure inside the inner receptacle when the inner receptacle is packed at 0°C and the temperature reaches 59°C is determined to be 123kPa (absolute value). In such an environment, the differential pressure, 63 kPa, between the inner pressure of the inner receptacle (123 kPa) and the ambient pressure (60 kPa), acts on the inner receptacle.
A.4.6.1. Stresses on body of the inner receptacle caused by internal/external pressure difference The inner receptacle has a shape of a rectangular parallelepiped, 760 mm in width, 443 mm in depth and 555 mm in height (inside dimensions). The inner receptacle is evaluated for stresses on the narrower lateral plate, wider lateral plate, bottom plate and upper plate of the body. The targets of the evaluation are maximum internal/external pressure differences.
(1) Stresses on narrower lateral plate (443 x 555 mm) of the inner receptacle The maximum bending stress generated on the narrower lateral plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the narrower lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.35 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the narrower lateral plate = 6 [mm].
These values are assigned:
6.3 x 102 x 4432
= 0.35 x = 120.3 [MPa]
62 Thus, the stress generated on the narrower lateral plate of the inner receptacle is lower than 183 MPa(75°C), the allowable tensile stress for the stainless steel. The margin of safety is:
183 Margin of safety = = 1.5 120.3 II - A - 33
(2) Stresses on wider lateral plate (555 x 760 mm) of the inner receptacle The maximum bending stress generated on the wider lateral plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the wider lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.45 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 555 [mm]
h: wall thickness of the wider lateral plate = 8 [mm]
These values are assigned:
6.3 x 102 x 5552
= 0.45 x = 136.5 [MPa]
82 Thus, the stress generated on the wider lateral plate of the inner receptacle is lower than 205 MPa, the allowable tensile stress for the stainless steel. The margin of safety is:
183 Margin of safety = = 1.3 136.5 (3) Stresses on bottom plate (443 x 760 mm) of the inner receptacle The maximum bending stress generated on the bottom plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the bottom plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load =6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the bottom plate = 6 [mm]
These values are assigned:
6.3 x 102 x 4432
= 0.49 x = 169.0 [MPa]
62 Thus, the stress generated on the bottom plate of the inner receptacle is lower than 183 MPa(75°C), the allowable tensile stress for the stainless steel. The margin of safety is:
183 Margin of safety = = 1.08 169.0 (4) Stresses on upper plate (443 x 760 mm) of the inner receptacle The maximum bending stress generated on the upper plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 II - A - 34
where max: maximum bending stress generated on the upper plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the upper plate = 10 [mm]
These values are assigned:
6.3 x 102 x 4432
= 0.49 x = 60.6 [MPa]
102 Thus, the stress generated on the upper plate of the inner receptacle is lower than 183 MPa(75°C),
the allowable tensile stress for the stainless steel. The margin of safety is:
183 Margin of safety = = 3.0 60.6 A.4.6.2. Stresses on inner receptacle rod bolts caused by the maximum internal/external pressure difference Rod bolts shown in Fig. I-1 are used to join the body of the inner receptacle with the lid. In our analysis, stresses are evaluated on the assumption that the rod bolts suffer stresses resulting from the maximum internal/external pressure difference (transmitted by the lid) and those resulting from the rod bolt tightening torque.
The tensile stress is represented as follows:
F T R
n AR K d AR where R: tensile stress generated on the section of the rod bolt [MPa]
F: load resulting from the maximum internal/external pressure difference which acts on the lid of the inner receptacle = 21211 [N] = (6.3 10-2)[MPa] (443 760) [mm2]
n: number of rod bolts = 16 AR: sectional area of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm]
These values are assigned:
21211 44130
= + = 184.2 [MPa]
16 x 157 0.1 x 16 x 157 Thus, the stress generated on the rod bolt is lower than the allowable tensile stress (712 MPa(75°C)) for the chrome molybdenum steel. The margin of safety is:
712 Margin of safety= = 3.9 184.2 These results of our analysis proved that the integrity of the inner receptacle which forms the containment boundary for the contents is preserved even when the ambient pressure drops and attains 60 kPa (absolute value) and thus that no leakage of radioactive substances occurs in the environmental condition.
II - A - 35
A.4.6.3 Evaluation of Repetitive Stress due to Internal Pressure The results evaluation of stress on the stainless steel inner receptacle body due to internal pressure in A.4.6.1 showed that maximum stress is 169.0 MPa and the stress amplitude is 84.5 MPa from 169.0÷2. The planned period of use for the packaging is 80 years, and the total number of transports is 160 times during the period of use. Occurrence 29,200 times (80x365 = 29,200 times) is considered, assuming transport once a day for 80 years as a more conservative condition than the planned use. According to the fatigue curve of stainless steel shown in (II)-A Figure 11, fatigue failure does not occur even if the stress amplitude is 100 MPa or less and repetitive stress is generated more than 107 times in an environment from room temperature to 700°C.
The results of evaluating chrome molybdenum steel rod bolts in A.4.6.2 showed that stress is 184.2 MPa and the stress amplitude is 92.1 MPa from 184.2÷2. Stress is considered to occur 29,200 times, the same as for stainless steel. According to the fatigue curve of chrome molybdenum stainless steel shown in (II)-A Figure 12, fatigue failure does not occur even if the stress amplitude is 206 MPa (3.0x104 psi) or less and repetitive stress is generated more than 106 times in an environment from room temperature to 371°C (700°F).
Thus, fatigue failure due to repetitive stress caused by internal pressure does not occur.
II - A - 36
A.4.6.4 Comparison with allowable stresses Table II-A-5 shows the analytical values of stress obtained and the corresponding allowable values.
Since all the analytical values are lower than the allowable values (analytical criteria), the required safety is ensured.
Table II-A-5: Analytical Values Of Stress Compared with Allowable Stresses Item Allowable Stress Analytical Value Margin of Safety
- 1. Stresses on inner walls of inner receptacle:
- Narrower lateral side 183MPa 120.3MPa 1.5
- Wider lateral side 183MPa 136.5MPa 1.3
- Bottom surface 183MPa 169.0MPa 1.08
- Top surface 183MPa 60.6MPa 3.0
- 2. Stresses on rod bolt for inner 712MPa 184.2MPa 3.9 receptacle II - A - 37
A.4.7. Vibrations The results of analysis of natural frequency showed that the natural frequency of the package is 29.8 Hz (details in (II)-A Attachment 3). Generally, the frequency of the excitation force received from trucks, trailers, etc., during transport is less than 20 Hz at the maximum, which is different from the natural frequency of the package. As shown in (II)-A Figure 13, at a frequency ratio of 0.67
(=20/29.8), the displacement amplitude factor is about 200% even without conservative consideration of damping. Generally, acceleration of the vibration generated by trucks, trailers, etc., during transport is less than 2G, even taking into account the passing over bumps, etc., so the load on the packaging is less than four times the load on the package, even if amplification is conservatively considered to be 200%.
Even considering that no deformation of the packaging is observed in the evaluation of stacking under normal conditions of transport ((II)-A.5.4) where the load is five times the weight of the packaging, there is no risk of damage or cracking of the packaging due to vibration occurring during transport.
(II)-A Figure 13. Resonance Curve of Force-induced Forced Vibration (Source) Masaharu Kuniena, Practical Mechanical Vibration (1984)
II - A - 38
A.5. Normal Conditions of Transport A.5.1. Thermal Tests Packages configured with the type GP-01 packaging are type A fissile packages and therefore do not need to be subjected to the thermal tests under normal conditions of transport which are necessary for type B packages. In fact, the Regulations require type A packages to be exposed to a solar radiation environment at 38°C until a constant surface temperature change pattern occurs, before being evaluated in the thermal tests under accident conditions of transport to which fissile packages must be subjected (Chapter II-B, section B.4 Normal Conditions of Transport).
Our analyses were based on the prerequisite that the package is exposed to a solar radiation environment at 38°C for one week. Numerical evaluations were carried out to verify that the containment formed by the inner receptacle of the package is maintained throughout this environmental exposure.
As determined for the inner receptacle in Chapter II-B, section B.4. Normal Conditions of Transport, the temperature range from the average temperature in the inner receptacle (59°C) to the lowest temperature (-40°C) was considered.
A.5.1.1. Summary of evaluation of temperatures and pressures The temperature and pressure of the package under normal conditions of transport should be determined from the highest temperature of the package attained in solar radiation conditions and the highest pressure formed by the temperature rise caused by solar radiation.
The analysis results shown in Chapter II-B, section B.4. Normal Conditions of Transport, reveal that the average temperature in the inner receptacle is 59°C. Under initial conditions of transport established by 0°C and 1 atmospheric pressure (101 kPa), the inner pressure in the inner receptacle which forms the containment boundary of the package is 144 kPa (absolute pressure), and the maximum internal/external pressure difference of the inner receptacle is 43 kPa (gauge pressure).
A.5.1.2. Thermal expansion The temperature rise in the package is not large. The structural materials of the package are metallic and have good thermal conductivity. The temperature differences between components of the package are small. Therefore, possible thermal expansion will not generate significant stresses on them. The main structural materials of the outer receptacle body, the outer receptacle lid, the inner receptacle body, and the inner receptacle lid are all made of stainless steel. The pellet storage box assembly that is contents is made of stainless steel. Therefore, possible thermal expansion due to contact combination of different kinds of materials will not generate stresses of them.
II - A - 35
As a result of the above, there is no significant stress due to thermal expansion, and there is no risk of cracking or breakage.
II - A - 36
A.5.1.3. Calculation of stresses We assume that an initial absolute pressure of 101 kPa is present in the inner receptacle at -40°C.
If the average temperature in the inner receptacle rises to 59°C (see section II-B.4.4. Maximum Inner Pressure), the inner pressure in the inner receptacle becomes 273 + 59
= x 101 = 144 [kPa.].
273 40 Accordingly, a gauge pressure of 43 kPa (=144-101) which corresponds to the maximum internal/external pressure difference acts on the inner receptacle.
Stresses generated on the inner receptacle will be described in the following paragraphs.
A.5.1.3.1. Body of inner receptacle The inner receptacle has the shape of a rectangular parallelepiped, 760 mm in width, 443 mm in depth and 555 mm in height (inside dimensions). The inner receptacle is evaluated for stresses on the inner walls of the narrower lateral plate, wider lateral plate, bottom plate and upper plate of the body. The targets of the evaluations are maximum internal/external pressure differences.
(1) Stress on narrower lateral plate (443 x 555 mm) of inner receptacle The maximum bending stress generated on the narrower lateral plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the narrower lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.35 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 4.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the narrower lateral plate = 6 [mm].
These values are assigned:
4.3 x 102 x 4432
= 0.35 x = 82.1 [MPa]
62 Thus, the stress generated on the narrower lateral plate of the inner receptacle is lower than 183 MPa(75°C), the allowable tensile stress for the stainless steel at 59°C. The margin of safety is:
II - A - 37
183 Margin of safety = = 2.2 82.1 (2) Stress on wider lateral plate (555 x 760 mm) of inner receptacle The maximum bending stress generated on the wider lateral plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the wider lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.45 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load =4.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 555 [mm]
h: wall thickness of the wider lateral plate = 8 [mm]
These values are assigned:
4.3 x 102 x 5552
= 0.45 x = 93.2 [MPa]
82 Thus, the stress generated on the wider lateral plate of the inner receptacle is lower than 183 MPa(75°C), the allowable tensile stress for the stainless steel at 59°C. The margin of safety is:
183 Margin of safety = = 1.9 93.2 (3) Stress on bottom plate (443 x 760 mm) of inner receptacle The maximum bending stress generated on the bottom plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the bottom plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 4.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the bottom plate = 6 [mm]
II - A - 38
These values are assigned:
4.3 x 102 x 4432
= 0.49 x = 114.9 [MPa]
62 Thus, the stress generated on the bottom plate of the inner receptacle is lower than 183 MPa(75°C),
the allowable tensile stress for the stainless steel at 59°C. The margin of safety is:
183 Margin of safety= = 1.5 114.9 (4) Stress on upper plate (443 x 760 mm) of inner receptacle The maximum bending stress generated on the upper plate of the inner receptacle by the maximum internal/external pressure difference is given in the equation:
pa 2 max h2 where max: maximum bending stress generated on the inner upper plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 4.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the upper plate = 10 [mm]
These values are assigned:
4.3 x 102 x 4432
= 0.49 x = 41.4 [MPa]
102 Thus, the stress generated on the inner wall (top surface) of the inner receptacle is lower than 183 MPa(75°C), the allowable tensile stress for the stainless steel at 59°C. The margin of safety is:
183 Margin of safety = = 4.4 41.4 A.5.1.3.2. Rod bolt for inner receptacle In our analyses, stresses are evaluated on the assumption that the rod bolt receives stresses generated by the maximum internal/external pressure difference (transmitted by the lid) and those generated by the rod bolt tightening torque.
The tensile stress is represented as follows:
II - A - 39
F T R
n AR K d AR where R: tensile stress generated on the section of the rod bolt [MPa]
F: load resulting from the maximum internal/external pressure difference which acts on the lid of inner receptacle = 14478 [N] = (4.3 10-2)[MPa] (443 760) [mm2]
n: number of rod bolts = 16 AR: area of the section of the rod bolt = 157 [mm2]
T: tightening torque for rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of rod bolt = 16 [mm]
These values are assigned:
14478 44130
= + = 181.5 [MPa]
16 x 157 0.1 x 16 x 157 Thus, the stress generated on the rod bolt is lower than 712 MPa(75°C), the allowable tensile stress for chrome molybdenum steel at 59°C. The margin of safety is:
712 Margin of satety = = 3.9 181.5 A.5.1.4. Comparison with allowable stresses Table II-A-5 shows the analytical values of stress obtained and the corresponding allowable values.
Since all the analytical values are lower than the allowable values (analytical criteria), the required safety is ensured.
Table II-A-5: Analytical Values Of Stress Compared with Allowable Stresses Item Allowable Stress Analytical Margin of Value Safety
- 1. Stresses on inner walls of inner receptacle: 183 MPa 82.1 MPa 2.2
- Narrower lateral side 183 MPa 93.2 MPa 1.9
- Wider lateral side 183 MPa 114.9 MPa 1.5
- Bottom surface 183 MPa 41.4 MPa 4.4
- Top surface
- 2. Stresses on rod bolt for inner 712 MPa 181.5 MPa 3.9 receptacle II - A - 40
A.5.2. Water Spray Parts of the packaging are covered with stainless steel plates which have high corrosion resistance.
All the joints are welded continuously. The threaded portion of the fusible plug has a high leaktightness guaranteed by an O-ring. Thus, the external surfaces of the packaging materials do not deteriorate with sprayed water, and water will not enter the heat insulator zones. Furthermore ,
the heat insulator is made of ceramic fiber and is free from deterioration by water. The flange of the body of the outer receptacle is designed with a level difference: the inner side is higher than the outer side. Thus, water (e.g., rainwater) is prevented from entering the outer receptacle through the interface between the body and the lid. No entry of sprayed water occurs in the package. No deterioration occurs in the materials in the package and no increase in weight occurs in the package.
Water ingress into the inner receptacle is taken into account in the criticality analysis.
A.5.3. Free Drop Test The gross weight of the package is less than 5000 kg. The packagings (prototypes) were subjected to drop tests in accordance with the Public Notice, Appendix 3, section 1, item RO(1): drop test from 1.2 meters. The results of the drop test combined with the results of analyses are interpreted to demonstrate the safety of the package.
A.5.3.1. Prototype tests Appendix 1 to Chapter II-A contains details of prototype tests. Two prototype packagings were prepared for the prototype tests. One (Prototype No. 1) was mainly reserved for considering orientations in which the specimen should be made to drop during a series of drop tests under normal and accident conditions of transport. The other (Prototype No. 2) was used in the main part of the prototype tests. The prototype tests include free drop tests (described in this section),
followed by penetration tests, Drop I (9 m drop) test and Drop II (1 m target) test. Throughout these tests, the same, single prototype (No. 2) was used.
Essentially, the prototype packagings have the same structure as that of an actual type GP-01 transport packaging. The only differences from the actual packaging are listed below.
- Dummy rods of lead are used as substitute contents;
- Weight adjusting materials were added;
- Accelerometers were installed for measuring accelerations;
- A small portion of the aluminum honeycomb elements was removed and a penetration hole was made in the outer receptacle to make space for installing the accelerometers;
- A normal type of stainless steel was used as the material for the packaging components instead II - A - 41
of boronic stainless steel.
None of these measures had a non-conservative effect on the specimen such as that of attenuating the degree of damage in the packaging.
The prototype tests were carried out on the test target permanently installed in the premises of Takasago facility of Kobe Steel, Limited. The test target consists of a 5 m x 3.5 m steel plate 42 mm in thickness mounted on a 100-ton concrete mass which has an underground height of 2.5 meters. For details of the prototype tests, refer to Appendix 1 to Chapter II-A.
In the drop orientation examination tests, various drop orientations were examined for the prototype packaging to be tested. Initially, three orientations were selected for Prototype No. 1:
horizontal orientation with the lid facing downward, horizontal orientation with the narrower side facing downward, and inclined orientation with one of the corners of the packaging facing downward. For details of the examinations, refer to Appendix 1 to Chapter II-A.
The prototype was subjected to drop tests in these three orientations from a height of 1.2 meters.
The prototype suffered no significant deformations in appearance in the first two horizontal orientations. Geometrical measurements showed a maximum deformation of 2 mm. During a drop test with its corner facing downward, the prototype suffered several tens of millimeters of deformation in one of the lifting attachments on the lid of the outer receptacle. This deformation was local, located only around the lifting attachment concerned.
These 1.2-meter drop examination tests were followed by 9-meter drop examination tests. The results of these tests also showed that the packaging dropped with its corner facing downward suffered the largest deformation. Therefore, the orientation with the packaging corner facing downward was adopted for the main drop tests of Prototype No. 2. During the main drop tests, Prototype No. 2 suffered a local deformation in the lifting attachment on the lid of the outer receptacle. The results of the main tests are shown in Table II-A-7.
II - A - 42
Table II-A-7: Results of 1.2-m Drop Tests Prototype Orientation of Specimen Results of Test
- Horizontal orientation with the lid facing downward. No significant deformations in appearance.
- Horizontal orientation with Measured deformations: 1 to 2 mm the narrower lateral side Volume reduction rate 0.24 %
Prototype facing downward No. 1 Local deformation of the zone on and around the lifting attachment on the lid of
- Inclined orientation with outer receptacle.
the corner facing downward Measured deformations: 17 to 40 mm Volume reduction rate 0.14 %
Local deformation of the zone on and around the lifting attachment on the lid of Prototype - Inclined orientation with outer receptacle.
No. 2 the corner facing downward Measured deformations: 20 to 36 mm Volume reduction rate 0.14 %
The Drop I and Drop II tests were also carried out as part of the entire series of tests. Upon completion of all the cases, the interiors of Prototypes No. 1 and No. 2 were checked (refer to Appendix 1 to Chapter II-A). The inner receptacle and the contents (pellet storage box assemblies) suffered small deformations but practically maintained their original shapes. No cracks were found in the stainless steel elements comprising the body and lid of the inner receptacle. The welds were not damaged. None of the bolts joining the body of inner receptacle with the lid was broken. Thus, the pellet storage box assemblies maintained their shape and capabilities. No openings through which uranium pellets might escape were produced in the pellet storage boxes. No separation or deformation occurred in the dummy neutron absorbers of the stainless steel plates applied to the inner surfaces of the inner receptacle. The fixing blocks were released from the dummy neutron absorber between the two pellet storage box assemblies but suffered no large deformations or large cracks. All these dummy neutron absorbers stayed in their effective zones delimited by the two pellet storage box assemblies and the lid of inner receptacle.
II - A - 43
A.5.3.2. Integrity of containment boundary The type GP-01 packaging has special structural features for maintaining the leaktightness of the inner receptacle which serves to confine nuclear fuel material:
- The inner receptacle is NOT FIXED to the outer receptacle. Therefore, if the package receives a drop impact, the inner receptacle moves in the space of the outer receptacle and strikes against the aluminum honeycomb element. The latter absorbs the impact energy. The honeycomb elements have a capacity which corresponds to more than the entire energy of a drop from a height of 1.2 meters;
- The rod bolts of the inner receptacle do not suffer any component of a stress which may be generated by the load of the two pellet storage box assemblies and the inner receptacle in any of its orientations except during lifting;
- The rod bolts of the inner receptacle are positioned in locations where they do not touch the frames. They will not suffer fatal damage even if its top strikes against the 2-mm thick inner plate of the lid of the outer receptacle.
As described above, the interiors of the prototypes were checked only after all the tests including Drop I and Drop II tests under accident conditions of transport were carried out. This means that the consequences of only the 1.2-meter drops were not checked.
Therefore, to evaluate the stress on the rod bolts, a set of conservative assumptions was adopted:
the highest acceleration (202 G) observed during the drop in horizontal orientation with lid facing downward of the four 1.2-meter drop tests of Prototypes No. 1 and No. 2 occurs and the rod bolts support the entire load of the contents during the drop. The following argument shows how this conservative assumption is justified for evaluating the stresses on the bolts.
The tensile stress is represented as follows:
F G T R
n A R K d AR where R: tensile stress generated on the section of the rod bolts [MPa]
F: weight of the contents = 5590 [N]
G: generated acceleration = 202 [G]
n: number of rod bolts = 16 AR: sectional area of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm].
II - A - 44
These values are assigned:
5590 202 44130 R 625.2 [MPa]
16 157 0.1 16 157 Thus, the overall stress generated on the rod bolt is lower than the allowable tensile stress (785 MPa) for the chrome molybdenum steel. The margin of safety is:
785 Margin of safety 1.2 625.2 Even on the conservative assumptions, the integrity of the containment boundary is maintained and the contents do not leak.
A.5.4. Stacking Test Instead of the compression test required by the Public Notice, Appendix 3, section 1, item RO(3),
only calculations were adopted to analyze the package. We assumed an event case where a compressive force equal to either the empty weight of the package multiplied by a factor of five (Wa) or a load of 13 kPa multiplied by the packages vertical projection area (Wb) (whichever is greater) is applied to the specimen of package. The equation needed for this calculation is Wa 5 1300 9.81 63765N Wb 13000 0.83 1.144 12344 N Since the relation Wa > Wb exists, the following analysis was carried out with the load Wa 63765N.
The packaging consists of an inner receptacle and an outer receptacle. Loads which may result from possible compressive forces from above will be applied to the outer receptacle, and not to the inner receptacle. For this reason, only the outer receptacle was evaluated.
Fig. II-A-14 shows a schematic diagram of the frames of an outer receptacle viewed from above. A set of frames for one outer receptacle consists of eight channel skeleton elements and four angle elements made of steel. Installed between the inner plates and the outer plates, these elements will support an eventual load from above. We assume here conservatively that the load Wa is applied only to the eight channel skeleton elements to evaluate the buckling stress per channel skeleton element.
II - A - 45
Angle element Channel skeleton element Outer plate Inner plate Fig. II-A-11: Schematic Drawing of Frames of Outer Receptacle (viewed from above)
For a pillar both of whose ends are fixed, the buckling load is determined by Johnsons equation:
c W Ac 1 2 2
4n E where A: sectional area = 750 mm2 E: Youngs modulus = 193000 [MPa]
- slenderness ratio of the channel skeleton element = l/k (l: buckling length) n: coefficient for fixed both ends = 4 c: critical compressive stress = 136.2 [MPa]
The radius of gyration of area k is determined as follows:
I k
A where I: geometrical moment of inertia of the channel skeleton element = 981250 [mm4].
- Hence, 981250 k 36.1 [mm]
750 Hence, the slenderness ratio is 682 18.8 .
36.1 Therefore, the buckling load per channel skeleton element is W 101988 [N]
Thus, the buckling load for the outer receptacle is higher than a load of Wa/8 (63765 N/8=7971 II - A - 46
N) acting on one channel skeleton element under a load five times the package empty weight. The margin of safety is:
101988 Margin of safety 12.7 7971 A.5.5. Penetration As shown in Appendix 1 to Chapter II-A, the penetration tests required in Public Notice, Appendix 3, section 1, item RO(4) were carried out as part of the prototype tests, on the central area of the lateral side(s) of the package which are not directly supported by the frames, the tightening rod bolts and the fusible plug. These components were not seriously damaged. Only the impact points on the surfaces of the outer receptacle were slightly dented.
A.5.6. Drop with Corner/edge Facing Downward The drop tests with the package corner or edge facing downward as specified in Public Notice, Appendix 3, section 1, item RO(2) are not required for the package considered, which is mainly constructed of stainless steel and whose maximum weight is 1300 kg.
A.5.7. Summary of Results and Evaluation The results of the thermal tests (A.5.1), water spray tests (A.5.2), and stacking tests (A.5.4) under normal conditions of transport showed that no damage such as deformation occurred in the inner or outer receptacle. Thus, these normal conditions of transport will not affect the contents of the package. The results of the free drop tests (A.5.3) and penetration tests (A.5.5) demonstrated that the containment capability of the inner receptacle was maintained despite several negligible local deformations observed on the package. Thus, the radioactive materials contained will not leak from the inner receptacle.
In consideration of these results, the shielding capability will be evaluated on the following assumptions:
- Conservatively, the outer receptacle is uniformly deformed by 5 mm. The deformations recorded during the drop tests (with the package corner facing downward) are not taken into account since they were local and did not touch the zone where the maximum dose equivalent rate was present;
- Despite the fact that the contents remained in the inner receptacle with the shapes and capabilities of the pellet storage box assemblies maintained, the analytical model of package with the interior of the inner receptacle will be simplified and homogenized to remain conservative;
- The aluminum honeycomb elements in the outer receptacle are crushed completely and the inner receptacle which contains a radiation source moves within the outer receptacle.
II - A - 47
A.6. Accident Conditions of Transport Type GP-01 package is classified as Type A package in which the radioactive material contained is less than the A2-value. Therefore, the accident conditions of transport specified for type B packages do not apply to the package.
The package is designed to contain more than 15 grams of fissile material (uranium-235). It should be tested under accident conditions of transport specified for transportation of fissile packages Details of the accident conditions of transport will be described in section A.9.2. Accident conditions for fissile packages to be transported.
A.7. Enhanced Water Immersion Tests This package is a Type A package in which the radioactive material contained is less than the A2-value and is not designed to contain radioactivity of more than ten thousand times the A2-value. Therefore, the package is not required to be subjected to the enhanced water immersion tests.
A.8. Radioactive Contents A.8.1. Characteristics of Contents (1) Major nuclides and their radioactivities i) Major nuclides: 232U, 234U, 235U, 236U, 238U, and 99Tc ii) Radioactivities: 37.5 GBq.
(2) Physical conditions of contents As presented in Chapter I-D (Contents of Packaging), (2) (Physical properties), the contents of the packaging are assemblies of pellet storage boxes which contain pellets of uranium oxides lined up on stainless steel corrugated plates, boxes stacked alternately with partitions which are penetrated by six pillars. One of two types of pellet storage box assembly (A or B) is used, depending on the type of pellet storage box. Figs. I-8 through I-11 show the structures of the two types of assembly.
(3) Limitation on content loading i) Enrichment It must be equal to or lower than 5.0 weight percent.
ii) Maximum storage
- When two Type A pellet storage box assemblies are installed: 264 kg of UO2
- When two Type B pellet storage box assemblies are installed: 200 kg of UO2.
Note: Type A (or Type B) assembly is not mixed with Type B (or Type A) assembly in one packaging.
iii) Kinds of enriched uranium Kinds of enriched uranium (other than regenerated enriched uranium) which meet the requirements in the American Society for Testing and Materials standard ASTM C996-04 ECGU:
232U 0.0001 µg/gU 234U 10 103 µg/g235U 236U 250 µg/gU II - A - 47
99Tc 0.01 µg/gU Note: When the condition 236U < 125 µg/gU is present, these criteria do not apply to 232U and 99Tc.
A.8.2. Behavior of Radioactive Contents under Normal Conditions of Transport The contents of the package were evaluated in thermal test, water spray tests, free drop tests, stacking tests and penetration tests under normal conditions of transport. The pellet storage box assemblies maintained their shape and capabilities. The inner receptacle which forms a containment boundary maintained its integrity. Therefore, the radioactive contents will not leak from the inner receptacle.
A.8.3. Behavior of Radioactive Contents under Accident Conditions Of Transport As a Type A fissile package, the package was subjected to Drop I (9 m drop) tests and Drop II (1 m penetrating bar) test under accident conditions of transport. During these tests, the pellet storage box assemblies maintained their shape and capabilities. The inner receptacle, the containment boundary of the package, was deformed under the accident conditions of transport. However, no cracks, fractures or openings through which uranium pellets might escape were produced in the inner receptacle/pellet storage boxes.
A.9. Fissile Package This package is a fissile package because it contains at least 15 grams of fissile material (uranium-235). This package does not attain criticality in the routine conditions of transport and meets the technical requirements specified in the Regulations, Article 11 as follows.
A.9.1. Normal Conditions of Transport for Fissile Packages Under the normal conditions of transport for fissile packages as defined in the Public Notice, Appendix 11, the package meets the requirements listed below.
A.9.1.1. Water spray As described in section A.5.2. Water Spray Tests, no deterioration occurs in the package materials, and no immersion occurs in the package. The subsequent criticality analysis conservatively will assume presence of water in the outer and inner receptacle in all the systems to be evaluated regardless of the nature of the system (isolation or array).
A.9.1.2. Free drop As shown in section A.5.3. Free Drop Test, free drop only causes local deformation in the package, and the inner receptacle nevertheless maintains its leaktightness. Drops in horizontal orientations of the package caused no significant deformations in its appearance as compared to drops with the package corner facing downward. In the subsequent criticality analysis, an arrayed system with shorter distance between two packages represents more demanding conditions. For this reason, systems in which movement of the inner receptacle is taken into account are II - A - 48
exposed to more demanding conditions.
For these reason, our criticality analysis considered the conservative condition that the outer receptacle is uniformly deformed and the aluminum honeycomb elements are completely crushed so that the inner receptacle moves in the outer receptacle. In this respect, it is clear that the consequences of accident conditions are more demanding than those of normal conditions. Thus, we adopt the principle that the results of criticality analysis under accident conditions of transport include those of normal conditions of transport.
A.9.1.3. Stacking test and penetration test As described in sections A.5.4 and A.5.5, the results of the stacking test proved that the stresses generated on the package are well below the allowable values. The results of the penetration test proved that a 6-kg rod does not penetrate into the package - more specifically, the outer plates of the package.
In both tests, the structural elements of the package were not broken and did not suffer any significant deformations that might affect the subsequent criticality analysis.
A.9.1.4. Results of criticality analysis Table II-A-8 shows the states of the package which was subjected to tests for fissile packages under normal conditions of transport and the test results to be considered in the criticality analysis. Results of these tests proved that no dents that might contain a 10-cm cube were generated under normal conditions of transport. Water immersion in the package and uniform deformations (or alteration of external dimensions) are assumed as prerequisites for the criticality analysis. However, the prerequisites for criticality analysis under accident conditions of transport include those under normal conditions of transport since the former are more demanding by definition.
Table II-A-8: States of Damage of Package under Normal Conditions of Transport Considerations in the Test Item State of Damage Remarks criticality analysis Water immersion is Water spray No damage considered Deformations (alterations In horizontal Uniform deformations 1.2 m drop of external dimensions of orientation of the are considered 1 to 2 mm) package No additional Stacking No damage -
consideration 6 kg rod Slight dent on the external No additional penetration surface of the package consideration A.9.2. Accident Conditions of Transport for Fissile Packages As stipulated in the Public Notice, Appendix 12, the specimen must be placed under either the first conditions (drop I, drop II, thermal test, and 0.9 m water immersion) or the second condition (15 m water immersion) (whichever generate more serious damage).
II - A - 49
In the second test condition (15 m water immersion), a differential pressure of 1.5 atm (152 kPa) is produced in the package, and the inner receptacle (constituting the containment boundary) on which a stress exceeding its bearing capacity starts deforming. With and despite its small contact surface, the O-ring allows the inner receptacle to maintain its water-tightness for a while, but once the flange of the inner receptacle suffers small deformations, the high external pressure overcomes the water-tightness and immersion begins. However, the immersion hole will not become large enough to allow uranium pellets to escape from the storage boxes. Therefore, nuclear fuel material does not escape from the inner receptacle in a large amount. The non-leaktight outer receptacle does not deform, and the non-leaktight aluminum honeycomb elements which prevent the inner receptacle from moving are not deformed either.
Thus, the first condition defined in the Public Notice, Appendix 12 is more demanding to the package than the second, because the outer receptacle and the honeycomb elements deform and the distance between two fuel packages in array is reduced.
A.9.2.1. Strength test: Drop I (9 m drop)
The package has a gross weight of 1300 kg and a specific gravity of 1.5. The package is not required to be subjected to Drop III tests. Therefore, two prototype packages were subjected to Drop I tests. One (Prototype No. 1) was reserved for considering drop orientations to be adopted during a series of drop tests under normal conditions of transport and accident conditions of transport. The other (Prototype No. 2) was used in the main part of the prototype tests. The prototype tests include free drop tests and penetration tests (refer to sections A.5.3 and A.5.5) before Drop I (9 m drop) test and Drop II (1 m penetrating bar) test. Throughout these tests, the same and single prototype was used. For details of the results of prototype tests, refer to Appendix 1 to Chapter II-A.
Essentially, the prototype packagings have the same structure as that of an actual model. The only differences from an actual model are listed below.
- Dummy rods of lead are used as substitute contents;
- Weight adjusting materials were added;
- Accelerometer was installed for measuring accelerations;
- A small portion of the aluminum honeycomb elements was removed and a penetration hole was made in the outer receptacle to make space for installing the accelerometers;
- A normal type of stainless steel was used as the material for the packaging components instead of boronic stainless steel.
None of these measures give rise to non-conservative effects on the specimen such as that of attenuating the degree of damage in the packaging. The free drop tests were immediately followed by the Drop I tests without installing additional measuring instruments on the specimen.
The prototype tests were carried out on the test target permanently installed in the Takasago facility of Kobe Steel, Limited. The test target consists of a 5 m x 3.5 m iron plate 42 mm in thickness placed on a 100-ton concrete mass which has an underground thickness of 2.5 meters. For details of the prototype tests, refer to Appendix 1 to II - A - 50
Chapter II-A.
In the drop orientation examination tests, various drop orientations were examined for the prototype packaging to be tested. Initially, three orientations were adopted: horizontal drop with the lid facing downward, horizontal drop with the narrower lateral side facing downward, and drop with one corner of the packaging facing downward. For details of the examinations, refer to Appendix 1 to Chapter II-A.
In accordance with the Public Notice, Appendix 12, drop tests must be carried out in such a way that the package is damaged most seriously during the thermal test. For the drop tests, an orientation was adopted for the package accordingly. Preliminary considerations and examination results for Prototype No. 1 were analyzed to choose the orientation of the package to be used definitively in the main part of the drop tests: orientation of the package with one of its upper corners facing downward. The upper corner of the package corresponds to the flange of the packaging and is most likely to form an entry route for heat. As drop tests, Drop I and Drop II were carried out on Prototype No. 2. Table II-A-9 shows the order of the series of tests of Prototypes No. 1 and No. 2.
However, the package orientation definitively chosen is not a demanding state of the package in terms of displacement of nuclear fuel, a phenomenon which is an important parameter for criticality evaluation. Accordingly, the evaluation parameters required for criticality evaluation are determined with account taken of the results of the examination tests (Drop I and Drop II) carried out on Prototype No. 1 in three orientations. For details of the results of the prototype tests, refer to Appendix 1 to Chapter II-A.
Table II-A-9: Consequence of Prototype Tests Test Test Item Prototype No. 1 Prototype No. 2 Conditions Horizontal lid downward Corner downward Normal Free drop Horizontal narrower lateral Conditions 1.2 side downward -
of Corner downward -
transport Penetration Steel rod penetration tests -
Horizontal lid downward Corner downward Horizontal narrower lateral -
side downward Drop I (9 m) Horizontal wider lateral side -
downward Inclined narrower lateral side -
downward Corner downward -
Horizontal near lifting point -
on lid onto penetrating bar Accident Horizontal near leg zone -
Conditions onto penetrating bar of Inclined near lifting point on Transport Drop II wider lateral side onto Corner onto penetrating bar (1m penetrating bar penetrating bar) Inclined center of wider lateral side onto penetrating -
bar Inclined flange on wider lateral side onto penetrating -
bar Thermal - (800°C, 30 minutes) 0.9 m water - -
immersion II - A - 51
A.9.2.1.1. Drop in horizontal orientation with lid facing downward A drop test of the package horizontally oriented with the lid facing downward caused 12 mm high bulges on the external lateral surface of the package under impact load. The top surface of the lid, the impact surface, deflected slightly between frames. No serious deformations occurred on the package. These results showed that the transport packaging has a high rigidity. More precisely, the package struck the steel plate of the test target in a slightly inclined orientation. Accordingly, deviations were observed in the deformations produced on the top surface of the package:
the deformations vary from 2 to 22 mm in the height dimension of the package. No significant deformations were noted on the other parts of the package. The rod bolts joining the body and lid of outer receptacle did not become loose.
A.9.2.1.2. Drop in horizontal orientation with narrower/wider lateral side facing downward (1) Drop with narrower lateral side facing downward During a horizontal drop with the narrower lateral side facing downward, bulges ranging from 12 to 14 mm were produced on the lid under impact load (refer to section A.9.2.1.1). No serious deformations occurred on the external surfaces of the package. More precisely, the package struck the test target in a slightly inclined orientation (lid first). Accordingly, the impact on the test target caused 7 to 17 mm reductions in length of the lid of the outer receptacle. The reductions in length of the body of the outer receptacle range from 1 to 6 mm. The rod bolts joining the body and lid of the outer receptacle did not become loose.
(2) Drop in horizontal orientation with wider lateral side facing downward During a horizontal drop with the wider lateral side facing downward, bulges ranging from 10 to 15 mm were produced on the lid under impact load (refer to section A.9.2.1.2). No serious deformations occurred on the external surfaces of the package. More precisely, the package struck the test target in a slightly inclined orientation (lid first). Accordingly, the impact on the test target caused 6 to 9 mm reductions in width of the lid of the outer receptacle. The reductions in width of the body of the outer receptacle range from 0 to 4 mm. The rod bolts joining the body and lid of the outer receptacle did not become loose.
A.9.2.1.3. Drop with corner facing downward Prototypes No. 1 and No. 2 which had been tested beforehand in four cases of drop event in the Drop I tests were subjected to this test. To provide an effect of superposition, the prototypes were released for a 1.2-meter free drop in the same orientation to strike the test target at the same impact point.
(1) Prototype No. 1 Deformations occurred in the package up to the flange. No openings that might form routes for entry of flames were generated in the package. Bolt seats near the deformations also deformed, but the rod bolts in the outer receptacle remained in place and were not broken. Some cracks were produced in the welds near the deformations.
No portion of the ceramic fiber insulator was lost. The impact zone of the package suffers a geometrical loss of an II - A - 52
inequilateral trigonal pyramid, 300 x 220 x 260 mm. The neighboring zone presents bulges of 20 to 22 mm in height.
(2) Prototype No. 2 Prototype No. 2 showed similar behavior to Prototype No. 1. Some cracks were found in the welds near the deformations, but no portion of the ceramic fiber insulator was lost. The impact zone of the package presents a geometrical loss of an inequilateral trigonal pyramid, 220 x 300 x 180 mm. The neighboring zone presents bulges of 12 to 18 mm in height.
A.9.2.1.4. Inclined drop test The edge of the package which struck the test target first was crushed. The package slipped slightly, but did not bounce or turn over the other way. Although the edge of the package struck the test target uniformly, the impact zone suffered different deformations depending on the location. This difference of deformations can probably be attributed to the displacement of the inner receptacle from its original position, caused by deformations of the honeycomb elements during the preceding three cases of Drop I. The crushed zone on the edge of the package varies from 10 to 58 mm. Cracks were produced in the welds between the lifting attachment and the outer plate in such a way that the ceramic fiber (insulator) became exposed. No portion of the insulator was lost.
A.9.2.1.5. Summary of results of Drop I tests (1) Damage on the package The transport packaging is designed with lower rigidity on the edge of the lid for absorbing impact energy resulting from accidental drop and collision, for example. The larger dimensions of deformations on the lid of the outer receptacle than those on the body can be attributed not only to the inclined state of the body when it struck the test target but also to the original lower rigidity of the lid edge.
Prototype No. 1 was subjected to three cases of free drop followed by five cases of Drop I. As a result, it deformed in various locations. Nevertheless, no cracks, fractures or penetration holes that might affect the interior of the package were generated, and the lid did not move from its required position.
Partial cracks were produced in the welds of the packaging during some of the tests with the body inclined and those with the corner facing downward. However, no portion of the insulator (ceramic fiber) was lost.
Deformations leading to opening of the flange did not occur. The rod bolts on the outer receptacle were not broken or released.
Results of tests of Prototype No. 2 were similar to or overridden by those of Prototype No. 1.
(2) Damage to package contents When all the tests including free drop, Drop I and Drop II were complete, the lid of the outer receptacle was removed and the internal elements were checked.
II - A - 53
(a) Prototype No. 1 The aluminum honeycomb elements were greatly deformed on the impact side, and some portions of the elements fell off. Deformations occurred on the lateral surfaces and the protective rectangular pipes for inner receptacle flange on the lateral surfaces of the outer receptacle. Thus, the inner receptacle obtained space for moving. No openings through which the contents might escape were created on the lid of the inner receptacle. Some small bulges were produced on the lateral surfaces of the inner receptacle, and no cracks or fractures were observed in the welds. Probably some synergetic effects of more than one event caused dents and penetration holes with some of the rod bolts of the inner receptacle on the back surface of the lid of the outer receptacle when they struck it.
Several rod bolts deformed, but none were broken. The lid of the inner receptacle remained in the initial position.
The stainless steel plates (which simulated neutron absorbers) applied to the inner surfaces of the inner receptacle stayed in their initial positions. They were not broken or deformed. All the fixing blocks on the stainless steel plate (which simulated neutron absorber) between the two pellet storage box assemblies (contents) were released. The simulated neutron absorber was slightly deformed near the fixing points. Nevertheless, this dummy neutron absorber did not suffer any significant deformations, cracks or fractures, and stayed in its effective zone delimited by the two pellet storage box assemblies and the lid of inner receptacle. Though slightly deformed, the pellet storage box assemblies maintained their initial shape and capabilities. The pillars and nuts were not broken. The partitions (simulated neutron absorbers) maintained their mutual distances. No cracks or clefts were produced in the partitions, which were deformed but did not leave their effective zones. The rubber blocks and locking screws for positioning the pellet storage boxes were not damaged. The pellet storage boxes maintained their initial positions. No openings through which radioactive materials might leak were produced.
(b) Prototype No. 2 The aluminum honeycomb elements were partially deformed in the outer receptacle. The rod bolts on the inner receptacle left no traces of strike against the inner surfaces of the outer receptacle. The inner receptacle remained on the urethane rubber guides almost in the initial position. The corners of the inner receptacle suffered only small deformations than those observed on the corresponding zone of the external of the outer receptacle. No significant deformations were created on the inner receptacle. The rod bolts did not fall off, and were not broken or deformed.
The stainless steel plates, simulated neutron absorbers, on the inner surface of the inner receptacle did not change their positions, and were not broken or deformed. Some of the fixing blocks on the simulated neutron absorber between the two pellet storage box assemblies were broken, but the simulated neutron absorbers suffered no significant deformations or fractures, thus remaining in their effective zones.
The pellet storage box assemblies maintained their practically sound shape and capabilities. No deformation or fracture were found in the pellet storage boxes, the pellet storage box positioning rubber blocks or the lock screws.
A.9.2.1.6. Inner receptacles content retainability The structural characteristics of the transport packaging described in section A.5.3.2 are also effective for II - A - 54
maintaining the content retainability of the inner receptacle under accident conditions of transport:
- Under drop impact, the inner receptacle - which is not fixed to the outer receptacle - moves in its surrounding void and strikes against the aluminum honeycomb elements, which are crushed to absorb the inner receptacles energy.
- The rod bolts in the inner receptacle are not placed under stresses that may be caused by the load of the pellet storage box assemblies in the inner receptacle in any l orientations of the package, except during lifting operation.
- Even if any of the rod bolts strikes the inner surface (covered with a 2-mm steel plates) of the lid of the outer receptacle, no fatal damage will occur since the rod bolts are installed in a zone where they will not touch the frames of the outer receptacle.
In the 9-meter drop test of the horizontally oriented Prototype No. 1 with the lid facing downward, the inner receptacle was exposed to an acceleration of 296 G. The direction of this acceleration is identical to that of the axis of the rod bolts. To assess stresses on the rod bolts, we assumed conservatively that they would be subjected to the load generated on the contents during this drop.
The tensile stress is represented as follows:
F G T R
n AR K d A R where R: tensile stress generated on the section of the rod bolt [MPa]
F: weight of the contents = 5590 [N]
G: acceleration generated = 296 [G]
n: number of rod bolts = 16 AR: area of the section of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm].
These values are assigned:
[MPa]
Thus, the stress generated on the rod bolt is lower than 930 MPa on this conservative assumption. The rod bolts do not break, the lid of the inner receptacle remains in the initial position, and the contents are not released outside from the inner receptacle.
A.9.2.1.7. Consideration of Drop I results in the criticality analysis As shown in section A.9.2.1.5. Summary of results of Drop I tests, no cracks, fractures or penetration holes that might affect the interior of the package were produced, and the lid stayed in its required position. No opening was caused on or near the flange. Adjusting the results of the structural analyses, our criticality analysis will assume conservatively that the outer receptacle is deformed uniformly in its entire body as follows:
II - A - 55
Height direction: Deformations of up to 22 mm occurred. Thus, uniform 25-mm deformations are assumed to occur.
Length direction: Deformations of up to 6 mm occurred in the body of the outer receptacle. Thus, uniform 10-mm deformations (20 mm in total on both sides) are assumed to occur.
Width direction: Deformations of up to 4 mm occurred in the body of the outer receptacle. Uniform 8-mm deformations (16 mm in total on both sides) are assumed to occur.
Moreover, we will assume in our criticality analysis that the aluminum honeycomb elements are crushed completely and fall off, and that the inner receptacle moves accordingly in its surrounding space in the inner receptacle, neglecting the thickness of the honeycomb elements (6 mm) resulting from complete crushing. Moreover, we will adopt a corrected distance that the external surface of the outer receptacle can travel under impact load toward the external surface of the inner receptacle, taking into account deformations of the internal parts of the outer receptacle conservatively:
Transversal direction of the package: 120 mm instead of 129 mm, the value actually measured.
Longitudinal direction of the package: 127 mm instead of 136 mm, the value actually measured.
Other assumptions for criticality analysis are: that no significant crack or deformations occur in the neutron absorbers in the inner receptacle which remain in their effective zones; that the pellet storage box assemblies remain within their initial installed positions in the inner receptacle; that the uranium pellets are not discharged from the storage boxes; and that the bulges and deformations observed in and on the inner receptacle and pellet storage box assemblies are negligible.
A.9.2.2. Mechanical strength tests: Drop II (1 m penetrating bar)
Prototypes No. 1 and No. 2 were subjected to Drop II tests immediately after the free drop and Drop I tests.
Appendix 1 to Chapter II-A shows the details of the results of the prototype tests.
The same prototype packages were used throughout all these tests, and no additional measuring instruments were installed on the specimens.
The penetrating bar consists of a soft steel cylinder 450 mm in length and 150 mm in diameter which has a smooth flat top surface and which is vertically welded onto the steel plate used for the preceding drop tests. The length (450 mm) of the cylinder is sufficient to reach the contents of the package if perfect penetration occurs into the package.
For detailed specifications for the penetrating bar, refer to Appendix 1 to Chapter II-A.
These prototype tests were carried out in the sequence shown in Table II-A-8. In the Drop II tests, Prototype No. 1 was made to drop in several cases of events: a drop with the body of the packaging inclined in such a way that the center of a lateral surface would strike the penetrating bar to achieve greatest deformations; a drop with the lid edge with less rigidity striking the penetrating bar; a drop with the flange and bolts striking the penetrating bar; a drop with the welded lifting attachment (lifting point) striking the penetrating bar, and a drop with a bottom leg striking the penetrating bar. The very same zones of Prototype No. 2 which had been most damaged during the preceding II - A - 56
free drop and Drop I tests were made to strike the penetrating bar.
A.9.2.2.1. Summary of results of Drop II tests Table II-A-10 shows the deformations recorded in the Drop II tests.
A drop with the lifting attachment striking the penetrating bar caused only small deformations because the bar struck the zone of the package behind which rigid frames were provided. No cracks were produced in the welds.
Even if cracks are produced in the welds, the ceramic fiber (insulator) will not be lost since large blocks of this material are positioned into the compartments between the inner plates and the outer plates of the outer receptacle (see the other cases of cracking in the welds produced in the preceding tests).
Adapted blocks of insulator are filled into the compartments formed by the inner and outer plates of the outer receptacle. Even in case of cleft, these blocks of ceramic fiber will not be lost from the compartments.
A 28-mm deformation occurred in the leg. No cracking occurred in the neighboring zones of the outer plates on which the leg had been welded. As expected, the wider lateral side of the inclined package deformed 55 mm from the initial surface. No cracks or deformations were produced on the outer plates.
The internal materials of both prototype packagings were checked after all the tests (free drop, Drop I, and Drop II) were completed. None of the deformations generated on the outer plates of the outer receptacle affected the inner plates of the outer receptacle. None of the loads applied to the prototypes during the Drop II tests affected the inner receptacle or the contents.
Small dents from the strike were observed on the outer plates and the flange on the wider side of the flange, but no openings that might form routes for flames from outside were produced.
The lifting attachment zone on the wider lateral side deformed very visibly because of its structural strength, and a weld cleft was produced in a zone which had not been filled with insulator. The lid did not move from its initial position and no opening was caused on or near the flange.
During five event cases of Drop II, some of the welds presented cracks, but the insulator was not lost. No cracks or penetrations occurred on the outer plates. The bolts were not broken and did not fall off.
Table II-A-10: Deformations in Drop II Tests Deformation Orientation Strike Zone Remarks (mm)
Horizontal Lifting attachment 14 on the lid Bottom leg 28 Inclined Lifting attachment 55 Prototype on the wider surface No. 1 Center of the wider 11 Trace of strike on the surface flange: 4 mm Flange on wider 14 surface Prototype Corner 7 No. 2 II - A - 57
A.9.2.2.2. Consideration of Drop II results for criticality analysis Dents were produced on the external surface of the outer receptacle in the Drop II tests. However, no penetrations, cracking or opening occurred on the external surface. The load applied during the tests did not cause deformations of or damage to the internal parts of the outer receptacle. Thus, the inner receptacle and the contents were not affected. Thus, consideration of the Drop II test results for criticality analysis is overridden by the consideration described in section A.9.2.1.7. Consideration of Drop I results in the criticality analysis.
A.9.2.3. Thermal test The thermal test is carried out immediately after the end of the drop tests. This thermal test takes into account the damage caused to the package during the preceding tests. An analytical model (proven for reliability) is used to evaluate the package, taking into account the results of prototype tests. The analysis will follow the official regulations: the package is placed in an environment kept at 38°C in solar radiation until the surface temperature of the package becomes constant; then it is placed in an environment kept at 800°C under thermal test conditions for 30 minutes and is returned for cooling to the initial environmental conditions at 38°C. Solar radiation is taken into account for the periods of time in which the package is placed under the thermal test conditions and in which it is cooled to 38°C. For details, refer to Chapter II-B, section B.5.
A.9.2.3.1. Stress on lateral plate of inner receptacle Table II-A-11 shows the highest temperatures obtained under accident conditions of transport. Refer to section B.5.3. Temperatures of Package.
As evaluated in section B.5.4. Highest Inner Pressures, if it is conservatively assumed that the interior of the inner receptacle is uniformly placed at 170°C as determined with the O-ring, with the leaktightness of the inner receptacle being maintained, the highest inner pressure of the inner receptacle is a gauge pressure of 63 kPa (absolute value:
164 kPa), which conservatively does not take thermal expansion into account.
Table II-A-11: Highest Temperatures of Parts of Package under Accident Conditions of Transport Part Highest Temperature (°C)
Before Thermal Test During/After Thermal Test Top of outer receptacle 129.0 798.2 Corner of outer receptacle 80.4 800.7 Wider lateral side of outer receptacle 61.8 736.1 Narrower lateral side of outer receptacle 62.2 737.4 O-ring of inner receptacle at corner 65.8 169.3 O-ring of inner receptacle on wider side 66.2 155.3 O-ring of inner receptacle on narrower side 66.5 169.7 II - A - 58
The results of prototype tests have shown that under the conditions of Drop I and Drop II tests, the contents are not discharged from the inner receptacle which constitutes a containment boundary. The contents to be stored in the packaging are less dissipative solids. Therefore, the package in question is not required to maintain leaktightness of the containment boundary under accident conditions of transport. The package will be evaluated below for stresses that may be generated on the inner receptacle on the assumption that inner pressure is present. We will compare the results of the numerical evaluation to the tensile strengths of the structural materials to verify that the inner pressure does not cause cracking or fracture in the components of the inner receptacle and that the inner receptacle continues to confine the contents.
(1) Stress on narrower lateral plate (443 x 555 mm) of inner receptacle The maximum bending stress generated on the narrower lateral plate of the inner receptacle by the maximum internal/external pressure difference is represented as follows:
pa 2 max h2 where max: maximum bending stress generated on the narrower lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.35 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the narrower lateral plate = 6 [mm].
These values are assigned:
6.3 10 2 4432 max 0.35 120.3 [MPa]
62 Thus, the stress generated on the narrower lateral plate of the inner receptacle is lower than 414 MPa, the allowable tensile stress for the stainless steel at 170°C.
(2) Stress wider lateral plate (555 x 760 mm) of inner receptacle The maximum bending stress generated on the wider lateral plate of the inner receptacle by the maximum internal/external pressure difference is represented as follows:
pa 2 max h2 max: maximum bending stress generated on the wider lateral plate of the inner receptacle
- stress constant for the rectangular plate = 0.45 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 555 [mm]
h: wall thickness of the wider lateral plate = 8 [mm].
These values are assigned:
II - A - 59
6.3 10 2 555 2 max 0.45 136.5 [MPa]
82 Thus, the stress generated on the wider lateral plate of the inner receptacle is lower than 414 MPa, the allowable tensile stress for the stainless steel at 170°C.
(3) Stress on bottom plate (443 x 760 mm) of inner receptacle The maximum bending stress generated on the bottom plate of the inner receptacle by the maximum internal/external pressure difference is represented as follows:
pa 2 max h2 max: maximum bending stress generated on the bottom plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the bottom plate = 6 [mm].
These values are assigned:
6.3 10 2 4432 max 0.49 168.3 [MPa]
62 Thus, the stress generated on the bottom plate of the inner receptacle is lower than 414 MPa, the allowable tensile stress for the stainless steel at 170°C.
(4) Stress on upper plate (443 x 760 mm) of inner receptacle The maximum bending stress generated on the upper plate of the inner receptacle by the maximum internal/external pressure difference is represented as follows:
pa 2 max h2 max: maximum bending stress generated on the upper plate of the inner receptacle
- stress constant for the rectangular plate = 0.49 (determined from the ratio of both sides of the rectangular plate) p: uniformly distributed load = 6.3 10-2 [MPa]
a: dimension of the shorter side of the rectangular plate = 443 [mm]
h: wall thickness of the upper plate = 10 [mm].
These values are assigned:
6.3 10 2 4432 max 0.49 60.6 [MPa]
10 2 Thus, the stress generated on the upper plate of the inner receptacle is lower than 414 MPa, the allowable tensile stress for the stainless steel at 170°C.
II - A - 60
A.9.2.3.2. Stress on rod bolt for inner receptacle The coefficient of thermal expansion of chrome molybdenum steel, the material used for the rod bolt for the inner receptacle, is smaller than that of stainless steel. Accordingly, when the ambient temperature rises, tensile stress occurs on the rod bolts. To determine the stress on a rod bolt, we assume conservatively that the entire thermal expansion results in strain in the rod bolt, omitting the thermal expansion of the rod bolts.
The tensile stress which is generated when a gauge pressure of 63 kPa acts on the inner receptacle is represented as follows:
F T R1 n A R K d AR where R1: tensile stress generated on the section of the rod bolts [MPa]
F: load which the maximum internal/external pressure difference generates on the lid of inner receptacle =
21211 [N] = 6.3 10-2 MPax(443 x 760mm2) n: number of rod bolts = 16 AR: sectional area of the rod bolt = 157 [mm2]
T: tightening torque for the rod bolt = 44130 [Nmm]
K: torque constant = 0.1 d: nominal diameter of the rod bolt = 16 [mm].
These values are assigned:
21211 44130 R1 184.2 [MPa]
16 157 0.116 157 Since the thermal expansion of the rod bolts is not taken into account, the stress resulting from thermal expansion difference in thermal expansion is determined from the strain multiplied by Youngs modulus simply on the assumption that the entire thermal expansion of the stainless steel:
R 2 E where R2: tensile stress generated on the section of the rod bolt [MPa]
- strain produced in the rod bolt by the thermal expansion of the stainless steel at 170°C (443 K)
(determined by interpolating between the two coefficient of thermal expansion of the stainless steel:
15.30 10-6 K-1 (at 400 K) and 16.25 10-6 K-1 (at 500 K)
E: Youngs modulus of the chrome molybdenum steel = 2.05 105 [MPa]
(a value adopted conservatively at the ambient temperature)
These values are assigned:
R 2 15.71 10-6 2.05 1053.3 [MPa]
II - A - 61
The sum of these stresses on the rod bolt is:
R R 1 R 2 184 .2 3.3 187 .5 [MPa]
Thus, the total stresses generated on the rod bolt are lower than 847 MPa, the allowable tensile stress for the chrome molybdenum steel at 170°C, and the rod bolts have a sufficient structural strength.
A.9.2.3.3. Comparison with allowable stresses Table II-A-12 shows the analytical values of stress obtained and the corresponding allowable stresses. In all the cases, the analytical values of stress are lower than the allowable values. Thus, no openings will be produced in the inner receptacle, and the contents will not escape from the inner receptacle.
Table II-A-12: Analytical values of stress compared with allowable values Item Allowable Stress Analytical Value
- 1. Stresses on inner walls of inner receptacle:
- Narrower lateral side 414 MPa 120.3 MPa
- Wider lateral side 414 MPa 136.5 MPa
- Bottom surface 414 MPa 168.3 MPa
- Top surface 414 MPa 60.6 MPa
- 2. Stresses on rod bolt for inner receptacle 847 MPa 187.5 MPa A.9.2.3.4. Consideration of thermal test results in the criticality analysis During the thermal test, non-metallic materials such as rubber in the outer receptacle were burnt, but the package underwent no significant geometrical alterations. The inner receptacle underwent a color change but there were no geometrical alterations. The temperature reached in the O-ring was lower than the normal service temperature. The neutron absorbers in the inner receptacle were not altered during the tests and the contents did not move or present any deformations or fractures. Thus, the results of the thermal test to be considered in the criticality analysis are included in those pointed out in section A.9.2.1. Mechanical strength tests: Drop I (9 m drop).
A.9.2.4. Water immersion Since the criticality safety analysis takes into account entry or infiltration of water into the inner receptacle, the regulatory water immersion tests under a 0.9 m water head were not carried out. In this respect, the density of water was surveyed to stay conservative in the criticality analysis.
A.9.2.5. Summary of accident conditions of transport During the Drop I and Drop II tests, Prototype No. 1 which had preliminarily been subjected to drop orientation examination tests presented no cracks, fractures or penetration holes that might reach the interior of the outer receptacle. The lid of Prototype No. 1 maintained its initial closed position. Prototype No. 2 showed similar II - A - 62
behaviors during the tests and the inner receptacle was not exposed.
The inner receptacle moved in the space of the outer receptacle which was enlarged under the loads applied during the tests. However, no cracking, fracture or penetration which might reach or affect the interior of the inner receptacle occurred in the outer receptacle. The lid of Prototype No. 1 maintained its initial closed position. The neutron absorbers simulated by boronic stainless steel plates suffered no significant damage and stayed in their effective zone. The pellet storage box assemblies (contents of the package) maintained their initial shape and capabilities. No openings from which pellets of uranium oxides might escape were created in the storage boxes.
During the thermal test, the outer receptacle was maintained their shapes except for the burned rubber materials on the external surfaces of the outer receptacle. The interior of the outer receptacle changed color. There was no burning of organic substances. The O-ring reached temperatures around 170°C in conservative analyses and maintained sufficient elasticity after undergoing the tests under accident conditions of transport. The neutron absorbers underwent no change of location, deformations or cracks. The temperatures of the pellet storage box assemblies (contents) did not exceed 170°C. They presented no traces of thermal loads applied in the tests.
For the purpose of criticality safety analysis, we adopt the conservative condition that the outer receptacle presents uniform deformation under accident conditions of transport, based on the test results, especially the deformations of Prototype No. 1 which underwent more than one case of drop.
For the inner receptacle, we also adopt the conservative condition that it moves in the space delimited by the outer receptacle, based on the test results of Prototype No. 1 which underwent more demanding test conditions.
Nevertheless, we assume that the nuclear fuel material (pellets of uranium oxides) remain in the pellet storage boxes which maintain their shape and capabilities. We also assume that the contents remain in the inner receptacle.
Table II-A-13 shows the conditions of the package which underwent tests under the accident conditions of transport for fissile packages and the test results to be considered in criticality analyses. Our criticality analysis conditions under accident conditions of transport shall include water immersion in the package and uniform deformation of the package.
II - A - 63
Table II-A-13: Conditions of Damage in the Package Tested under Accident Conditions of Transport Test Results to be Test Damage in Package Considered in the criticality Remarks analysis Reductions in external Reductions in external dimensions. dimensions are taken into Deformations: account.
- Height: 22 mm max. Deformations:
- Length: 6 mm max. - Height: 25 mm uniformly
- Width: 4 mm max. - Length: 10 mm uniformly
- Width: 8 mm uniformly The inner receptacle Movements of the inner moved. receptacle are taken into Final distance between account.
external surface of outer Possible final distance receptacle and external between external surface of surface of inner receptacle: outer receptacle and Drop I - Package transversal external surface of inner -
direction: 129 mm receptacle:
- Package longitudinal - Package transversal direction: 136 mm direction: 120 mm
- Package longitudinal direction: 127 mm The neutron absorbers Neutron absorbers are remained in their effective installed in their effective zones. zones.
The fuel in the inner Movement is not taken into receptacle did not move. account for the fuel.
The inner receptacle and Neglected conservatively contents presented deformations.
Local deformations which No consideration Drop II did not affect the inner -
receptacle and contents.
No changes that might No consideration Thermal test affect the criticality analysis -
occurred.
Water immersion Water immersion is taken tests into account.
II - A - 64
A.10. Conclusion of Structural Analysis The package was subjected to structural analyses in routine conditions of transport, under normal and accident conditions of transport. The results obtained show that the package meets the requirements of each evaluation item.
The consequences observed in the package under these test conditions will be taken into account in other analyses.
Table II-A-14 shows summarized results of the structural analyses.
Table II-A-14: Results of Structural Analyses (1/2)
Condition Margin s Designation Analyses Criteria Results of Safety
- 1. Chemical and electrical reactions (1) Chemical Reactivity No chemical reaction No chemical reaction -
reactions occurs. occurred.
(2) Electrical Potentiality No electrical potential No electrical potential -
reactions difference is present difference was present between different between different materials. materials.
Routine Conditions of Transport
- 2. Low-temperature strengths (1) Structural Low-temperature No reduction in No reduction in elements strength performance occurs. performance occurred.
(2) Shock absorbers Low-temperature No reduction in No reduction in strength performance occurs. performance occurred.
(3) Spacers and Reduction in No reduction in No reduction in -
O-ring performance performance occurs. performance occurred.
(4) Insulator Reduction in No reduction in No reduction in -
performance performance occurs. performance occurred.
(5) Rod bolts Low-temperature No reduction in No reduction in -
strength performance occurs. performance occurred.
- 3. Containment Operational errors No operational error No operational error -
system will open the opened the containment system. containment system.
II - A - 65
- 4. Lifting Devices (1) Outer receptacle, Combined stress 205 MPa 58.6 MPa 3.4 lifting attachment, A-section (2) Outer receptacle, Combined stress 205 MPa 115.0 MPa 1.7 lifting attachment, section B (3) Outer receptacle, Shear stress 72 MPa 41.0 MPa 1.7 box-shaped lifting attachment, weld (4) Outer receptacle, Tensile stress 125 MPa 12.4 MPa 10.0 weld between lifting attachment and lid (5) Outer receptacle, Tensile stress 785 MPa 186.5 MPa 4.2 rod bolt (6) Inner receptacle, Combined stress 205 MPa 20.3 MPa 10.0 lifting attachment, A-section (7) Inner receptacle, Combined stress 205 MPa 87.1 MPa 2.3 lifting attachment, section B (8) Inner receptacle, Combined stress 125 MPa 88.3 MPa 1.4 lifting attachment, weld (9) Inner receptacle, Tensile stress 785 MPa 184.6 MPa 4.2 rod bolt
- 5. Tie-down system - - N/A -
- 6. Pressures (1) Inner receptacle, Bending stress 183 MPa 120.3 MPa 1.5 narrower lateral side (2) Inner receptacle, Bending stress 183 MPa 136.5 MPa 1.3 wider lateral side (3) Inner receptacle, Bending stress 183 MPa 169.0 MPa 1.1 bottom surface (4) Inner receptacle, Bending stress 183 MPa 60.6 MPa 3.0 top surface (5) Inner receptacle, Tensile stress 712 MPa 184.2 MPa 3.9 rod bolt
- 7. Vibration Deformation, No deformation nor No deformation or -
fracture fracture occurs fracture occurred.
II - A - 66
Table II-A-13: Results of Structural Analyses (2/2)
Margin Conditions Designation Analyses Criteria Results of Safety
- 1. Pressures (1) Inner receptacle, Bending stress 183 MPa 82.1 MPa 2.2 narrower lateral side (2) Inner receptacle, Bending stress 183 MPa 93.2 MPa 1.9 wider lateral side (3) Inner receptacle, Bending stress 183 MPa 114.9 MPa 1.5 bottom surface (4) Inner receptacle, Bending stress 183 MPa 41.4 MPa 4.4 top surface Normal Conditions of Transport (5) Inner receptacle, Tensile stress 712 MPa 181.5 MPa 3.9 rod bolt
- 2. Water spray Deterioration of No deterioration of No deterioration of materials. material occurs. material occurred.
Internal water No water immersion No water immersion immersion occurs inside. occurred inside.
- 3. Free drops Horizontal, lid Deformations, Amount of Body: 1 to 2 mm downward. fractures deformation Corner: 17 to 40 mm Horizontal, narrower side downward. State of damage Local small Inclined, corner deformations downward occurred, but no significant ones.
Leakage of No leakage of No leakage of contents contents occurs. contents occurred.
- 4. Stacking Bucking load 101988 N 7971 N 12.7
- 5. Penetration Penetration No penetration No penetration occurs. occurred.
II - A - 67
- 1. Drop I Horizontal, lid Deformations, Amount of Height: 2 to 22 mm -
downward. fractures deformation Length: 1 to 6 mm Horizontal, narrower Width: 0 to 4 mm side downward. Corner: 180 to 300 Horizontal, wider mm side downward.
Inclined, narrower State of damage - No cracks, fractures -
side downward. or penetrations that Inclined, corner might reach the downward interior
- Lid stayed in the required position.
- 2. Drop II - No loss of insulator
- No flange opening, Horizontal, lid. rod bolt fracture or Accident Conditions of Transport Horizontal, near a fall-off leg. Effect on contents -
Inclined, wider side, - Additional space -
lifting attachment. generated for inner Inclined, wider side receptacle to travel center. - No opening in inner Inclined, wider side receptacle for flange contents to escape
- Contents maintained their initial geometry.
- Neutron absorber maintained capabilities.
- 3. Thermal test Deformations, Amount of No deformation -
fractures deformation occurred.
State of damage No serious -
deterioration or deformation occurred.
Effect on contents - Contents did not move or escape.
Neutron absorber was not affected.
- 4. Water immersion - - Water immersion is -
taken into account in the criticality analysis.
II - A - 68
References
- Japan Stainless Steel Association, Data Book on Stainless Steel,
- The Japan Society of Mechanical Engineers design and construction standard JSME S NC1-2001: Standards for Nuclear Facilities for Electric Power Generation
- The Japan Society of Mechanical Engineers, New Edition of Manual for Mechanical Engineering
- The Japan Institute of Metals, Data Book on Metals, 3rd revised edition
- Nikkei BP, Re-Introduction to Material Mechanics
- U.S. NRC Regulations (10FCR), Part 71.45, Lifting and tie-down standards for all packages
- Japan Welding Society, Manual for Welding, 3rd revised edition
- IAEA Safety Standards: Regulations for the Safe Transport of Radioactive Material, 2005 Edition, Safety Requirements No. TS-R-1
- IAEA Safety Standards: Series Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material, Safety Guide No. TS-G-1.1
- Japanese Standards Association, Essential Points of Screw Tightening Mechanism, 3rd revised edition
- The Japan Society of Mechanical Engineers, Data for Heat Transfer Engineering, 4th revised edition II - A - 69
Appendix 1 to Chapter II-A Results of Prototype Drop Tests II - A.App1 - 1
- 1. Introduction The document describes the results of prototype drop tests carried out on the Type GP-01 transport packaging developed by Nuclear Fuel Industries, Ltd. for transporting pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium, enriched to 5 weight percent or less. Two prototype packagings were subjected to a consequent series of drop tests: 1.2-meter free drop tests and penetration tests under normal conditions of transport to be carried out on type A packages, 9-meter drop tests under accident conditions of transport to be carried out on fissile packages, and 1-meter target tests.
- 2. Description of Transport Packaging (1) Designation: Type GP-01 (2) Category of package: Type A fissile package (3) Maximum enrichment: 5.0 weight %
(4) Contents: Two pellet storage box assemblies of category either A or B (5) Limitations on content loading:
- When two pellet storage box assemblies A are installed: 264 kg or less of UO2
- When two pellet storage box assemblies B are installed: 200 kg or less of UO2.
(6) Dimensions:
- Width: 830 mm
- Length: 1144 mm
- Height: 1060 mm.
Note: These values of dimension take into account the legs and the portions of the lifting attachments which protrude from the flush surfaces of the packaging.
(7) Weight
- Gross weight of a packaging: 730 kg or less
- Gross weight of a package (packaging + contents): 1300 kg. or less (8) Principal materials
- Structural material: Stainless steel
- Heat insulators: Ceramic fiber
- Neutron absorbers: Boronic stainless steel
- Shock absorbers (honeycomb element): Aluminum
- Rod bolts: Chrome molybdenum steel II - A.App1 - 2
- Nuts: Stainless steel
- Spacers and skids: Silicone rubber, neoprene rubber, urethane rubber.
(9) General Characteristics Fig. II-A.App1-1 shows a general view of the package. The transport packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle. The outer receptacle has a multi-caisson-shaped double structure composed of frames, inner plates, and outer plates. The voids between the inner plates and the outer plates are filled with a heat insulating material. The lid of the outer receptacle has the same structure as that of the body of the outer receptacle. The lid of the outer receptacle is firmly joined to the body of the outer receptacle by means of rod bolts.
The body of the inner receptacle as well as the lid of the inner receptacle has a caisson-shaped single structure composed of thick stainless steel plates. An O-ring is provided for sealing on the flange surface. Like the outer receptacle, the lid of the inner receptacle is joined to the body of the inner receptacle by means of rod bolts.
One of the boronic stainless steel plates is installed as partition between two pellet storage box assemblies (contents).
The packaging is designed to contain two assemblies of pellet storage boxes which contain pellets (minimum elements of nuclear fuel). To construct an assembly, pellet storage boxes are stacked alternately with partitions which are penetrated by six pillars. The stacks of pellet storage boxes are fixed with nuts at the threaded tops of the pillars. All the partitions except for the uppermost and lowermost ones are boronic stainless steel plates which serve as neutron absorbers.
Two configurations can be selectively adopted for the pellet storage box assembly depending on the type of the pellet storage box: assembly A consisting of twelve (12) pellet storage boxes which can contain up to 11 kg of UO2 per box, and assembly B consisting of five (5) pellet storage boxes. One pellet storage box has a capacity of 20 kg of UO2. Thus, an assembly A is capable of containing up to 132 kg of UO2, and an assembly B up to 100 kg of UO2.
II - A.App1 - 3
Lifting attachment Lid of Outer Receptacle Fusible plug Flange Lid of Inner Receptacle Pellet storage box assembly Outer receptacle rod bolt Body of Outer Receptacle Inner receptacle lid bar bolt Flange spacer Aluminum honeycomb Assembly cover Body of Inner Receptacle Inner plate Outer plate Insulator Leg Fork guard Fig. II-A.App1-1: General View of Type GP-01 Transport Package II - A.App1 - 4
- 3. Tests 3.1. Prototypes Prototypes No. 1 and No. 2 were prepared. Prototype No. 1 was mainly used for examining and verifying orientations of the package to be adopted for the 1.2-meter free drop tests and 9-meter drop tests and for checking the outcomes of the penetration tests and 1-meter target tests. Prototype No. 2 was used in the main part of the tests. In the package orientations determined in the preliminary tests with Prototype No. 1, both prototypes were subjected to a consecutive series of free drop tests, 1-meter drop tests and 1-meter target tests. In the main tests, the prototypes were released for drop in the same orientation to strike consecutively the steel plate of the test target or the penetrating bar with the same impact point in order to achieve an effect of superposition.
Essentially, the prototype packagings were constructed by the same processes and have the same structure as a production mode of Type GP-01 transport packaging. However, for the purpose of drop tests, these prototypes have been designed with several features. The differences from a production packaging are described in the following paragraphs. Two pellet storage box assemblies A were used as the contents of the package because of the greater loading capacity of the type of assembly.
Photos A.App1-1 through A.App1-4 show general views of the prototype packaging.
(1) Dummy contents The prototypes to be subjected to the drop test contain lead rods (dummy pellets) instead of real pellets of uranium oxides since packagings containing real pellets of uranium oxides cannot be subjected to physical tests. The total weight of the dummy pellets was simulated but adjusted to become greater than the maximum loadable weight of real pellets in the pellet storage boxes. Each of the specimens contains dummy pellets which are at least 2 weight percent or at least five kilograms heavier than the weight of actual contents. This excess of weight was expected to have a conservative effect on the behaviors of the contents during the drop tests.
(2) Addition of gross weight adjusting material Even fully loaded with dummy pellets of lead, the gross weight of the package does not reach the nominal maximum weight (1300 kg). To make the prototype packages exceed the nominal maximum weight, lead plates were attached to the top and bottom surface of the pellet storage box assemblies in the inner receptacle. This weight adjustment carried out for the interior of the inner receptacle was expected to act effectively on the behaviors of the inner and outer receptacle during the drop tests. Photos A.App1-5 and A.App1-6 show the weight adjusting materials attached.
(3) Attachment of accelerometers Three-axis accelerometers were installed at points not facing downward on the lateral sides of the outer and inner receptacle to measure drop impact accelerations. Each of the accelerometers was fixed onto a dedicated bracket welded firmly on the package with two screws as recommended by the manufacturer of the instrument. These screws were treated with an adhesive to prevent easy loosening by vibration duringthe II - A.App1 - 5
transport and drop tests. The accelerometers and cables were protected with epoxy resin. Cable guides which serve as cable protectors were welded near the accelerometer brackets. As protecting materials, adhesive tapes and other packing materials were applied to the accelerometers shortly before the start of the tests.
These measures would represent only a very small portion of the gross weight of the prototype packaging.
Nevertheless, they contributed to increasing it. Photos A.App1-7 and A.App1-8 show the accelerometers attached to the package.
(4) Slight modifications of the packaging for attaching accelerometers A small portion of the honeycomb elements was removed to ensure space for the accelerometers and to protect them and the cables. A hole was made in the outer receptacle to make cabling space for the accelerometer installed on the inner receptacle. This cabling hole has an inner diameter of 30 mm. The insulator concerned was removed and a steel pipe was welded on the hole. As Prototype No. 1 was to be subjected to drop tests in various orientations, the cabling hole had to be made on the narrower lateral side which would be least affected by any of the drop tests. For Prototype No. 2, for which only one orientation was to be chosen for drop tests, a cabling hole was created on the bottom surface where the legs would serve as guards for the cables (described later in detail). Fig. II-A.App1-2 shows the positions of the cabling holes.
Photos A.App1-9 and A.App1-10 show the cabling holes on Prototypes No. 1 and No. 2.
These machining processes were completed before adjusting the gross weight of the package and did not offset the excess weight achieved over the nominal maximum gross weight of the prototype packaging.
Outer Receptacle Inner Receptacle Penetration hole in Prototype No. 1 Penetration hole in Prototype No. 2 Fig. II-A.App1-2: Positions of Cabling Holes for Accelerometers (5) Dummy neutron absorbers Stainless steel plates were used instead of the real neutron absorbers consisting of boronic stainless steel plates in the inner receptacle and pellet storage box assemblies. These dummy neutron absorbers have the same dimensions as those of the real ones. Neutron absorbers are not considered as part of the guarantee conditions of the mechanical strengths of the transport packaging.
II - A.App1 - 6
(6) Differences of prototype packaging from production model of packaging The characteristics of a definitive production model of packaging will be determined once improvements in features and handling operations have been identified and after the completion of manufacture of these prototype packagings or completion of all the tests described in this document have been taken into account.
Table II-A.App1-1 shows modifications in the prototype packaging which have thus been adopted. These modifications do not cause reduction in strength or increase in weight of the packaging, which would lead to reduction of the margin of safety for the characteristics of the packaging.
II - A.App1 - 7
Table II-A.App1-1: Modifications of Prototype Packaging for Definitive Production Model Element Modifications Improvements Consequences of Modifications Outer receptacle flange Spacer width was reduced to allow the spacer to Adhesiveness during The function to be performed by outer spacer avoid the uneven weld surface on the flange. construction was improved. receptacle flange spacer is not affected.
The dimensions around the rod bolts were Interference was eliminated for increased. better workability.
Lifting attachment Sharp portions on the bottom end of the Operational safety was This modification does not affect the strength.
corners were chamfered additionally. improved.
Outer receptacle Additional machining for better flatness. Workability during tightening The function to be performed by outer positioning pin was improved. receptacle positioning pin is not affected.
Process of attaching Nuts were welded on the back surface of the Machinability during The function to be performed by outer outer receptacle flange: portions of the flange were threaded construction was improved. receptacle positioning pin is not affected.
positioning pin additionally.
Aluminum honeycomb Honeycomb elements were no longer fixed Maintainability was improved. The characteristics of the honeycomb element element with an adhesive, but with a dedicated cover Repairability was improved. were not modified. This modification will not II - A.App1 - 8 and screws. affect results of drop tests.
Fixing process was changed to eliminate the Possibility of entry of foreign gaps between blocks matter into the gaps was eliminated.
Fixing method for the aluminum plate cover on Maintainability was improved.
the honeycomb plates was modified to avoid Repairability was improved.
use of adhesive agent.
The width of honeycomb for the narrower Non-functioning zones were The zones concerned do not work. The lateral side was changed. removed. modification does not affect test results.
Urethane rubber guide MC nylon was applied to the tip of the Slidability during The function to be performed by urethane urethane rubber guide. introduction/retrieval of inner rubber guide is not affected.
receptacle was improved.
Lid of outer receptacle Internal frame gaps were modified and Strength under severe service The strength of the outer receptacle frame is reinforcing plates were added. Spacing for conditions was enhanced. enhanced.
ventilation holes was modified.
Flange Flange clearance was reviewed. Machinability during Strength is not affected.
construction was improved.
Workability was improved.
Leg Bottom corner was chamfered. Positioning for two-stage The function to be performed by leg is not stacking was facilitated. affected.
Dimensions of skid Skid was shortened. Positioning for two-stage The function to be performed by skid is not stacking was facilitated. affected.
Process of attaching a Nut was no longer welded on the leg, but a Maintainability was improved. The function to be performed by skid is not skid threaded boss was imbedded. Repairability was improved. affected.
Edge of lid of the Additional chamfering was carried out. Workability was improved. This modification does not affect the strength.
inner receptacle and lid Operational safety was bar enhanced.
External surface of Mirror finishing is no longer carried out. Maintainability was improved. This modification does not affect the strength.
inner receptacle Spacing between rod Modification as a result of the modification of Interference during collision is This modification does not affect the strength.
bolts for inner frame gaps of the lid of the outer receptacle prevented.
receptacle Rod bolt seat on inner Rod bolt seat was designed as a longer hole. Workability was improved. This modification does not affect the strength.
receptacle Threaded portion of Threaded portion was made longer. Dimensions after tightening This modification does not affect the strength pillar for pellet storage were optimized. of the assembly.
box assembly II - A.App1 - 9 Process of fixing pillar Welding was replaced by a detachable structure. Maintainability was improved. This modification does not affect the strength for pellet storage box Repairability was improved. of the assembly.
assembly Process of lifting pellet Insert an eye bolt into the threaded hole was Design was simplified. This modification does not affect the strength storage box assembly replaced by Attach an eye nut to the pillar. of the assembly.
Eye nut holder Eye nut holders were added on the top surface Workability was improved. This addition of elements does not affect the of the pellet storage box assembly gross weight of the package.
Rubber block for Lugs were added at both ends. Workability was improved. This modification does not affect the storage positioning pellet boxs pellet retaining capability.
storage boxes Pellet storage box The width of the handle was reduced. Workability was improved. The function to be performed by pellet storage assembly cover box assembly cover is not affected.
Note: Since the sum of these modifications does not add to the package gross weight (1300 kg), the validity of the test results is maintained.
3.2. Drop test facility (1) Test target The test target used for the drop tests was that permanently installed in the premises of Takasago Facility of Kobe Steel Limited. Fig. II-A.App1-3 shows the general configuration of the test target. Photos A.App1-11 and A.App1-12 show the test target.
Fig. II-A.App1-3: Test Facility for Drop Tests Near the test target, a pit for high-speed camera and a backboard with checkered pattern are provided. To carry out a drop test, the walking crane is maneuvered to raise the specimen to the specified height, and a wire cutter is maneuvered to cut the lifting wire to release the specimen. Fig. II-A.App1-4 shows a plan of the test target.
II - A.App1 - 10
Camera pit 17m Facility Building 5m Drainage 3.5m ditch Backboard 5m Measuring booth Plan of Test target Note: The test target, which is 100 mm high from ground level, has a steel plate mounted on it .
Fig. II-A.App1-4: Plan of Drop Target The test target consists of a 5 m x 3.5 m steel plate 42 mm in thickness mounted on a 100-ton concrete mass which has an underground height of 2.5 meters. Specimens of up to 10 tons can be tested on this facility. For details of the construction of the test facility, refer to Fig. II-A.App1-5.
Steel plate 5 m x 3.5 Concrete mass Ground 2.5 Steel plate Notes: The steel plate is level. The reinforcing bars are spaced with 50-cm pitches.
Fig. II-A.App1-5: Construction of Drop Test Target II - A.App1 - 11
(2) Steel rod for penetration test The steel rod to be used for the penetration test must have the characteristics specified by the regulations:
- Weight: 6 kg
- Size: 3.2 cm in diameter
- Shape: Rod with hemispherical tip.
The steel rod prepared for the tests of the Type GP-01 transport packaging has the following characteristics:
- Weight: 6.3 kg (measured value)
- Size: 3.2 cm in diameter, 101.6 cm in length
- Shape: Rod with hemispherical tip (radius of hemisphere: 1.6 cm)
- Material: SS400; yield strength: 234 to 260 MPa
- Surface: Material exposed, no coating
- Appearance: See Fig. II-A.App1-6.
M16, depth 25 1016 32 R16 Unit: mm Fig. II-A.App1-6: Steel Rod for Penetration Test II - A.App1 - 12
(3) Penetrating bar for 1-meter drop tests The penetrating bar to be used for 1-meter drop onto penetrating bar tests must have the characteristics specified by the regulations:
- Installation: Vertically fixed
- Material: Mild steel
- Size: 15 cm in diameter, 20 cm in length
- Shape: Rod with round section, the top surface of which is horizontal, flat and smooth.
The penetrating bar prepared for the tests of the Type GP-01 transport packaging has the following characteristics:
- Installation: Vertically welded and fixed on the steel plate of the drop test target
- Shape: Rod with round section, the top surface of which is horizontal, flat and smooth
- Material: SS400; yield strength: 234 to 260 MPa
- Length: 45 cm, length which would allow the rod to penetrate a thickness of 24.5 cm from the package leg side: the length of the leg (14 cm) plus the distance from outer plate to inner plate of the outer receptacle (10.5 cm) if it is not strong enough
- Surface: Painted yellow all over so that races of rod contact may be left on the package
- Appearance: Refer to Fig. II-A.App1-7.
Unit: mm Fig. II-A.App1-7: Penetrating Bar for Drop Test II - A.App1 - 13
3.3. Test Event Cases Preliminary examinations were carried out to determine the test event cases to be adopted for testing two prototypes of Type GP-01 transport packaging under normal conditions and accident conditions. We decided to use Prototype No. 1 mainly for finding the orientations for causing maximum damage to the specimen, and Prototype No. 2 was reserved for the main tests only. The Regulations stipulate that specimens should be subjected to drop tests so that they are damaged as much as possible during the thermal tests which should follow the drop tests. The package has a box-like shape. The edges and corners of the package which constitute the joints of surfaces are most liable to deformation under the concentrated energy of the drop.
Therefore, if the package is so positioned that a corner of the package strikes the test target (or the penetrating bar) first in the drop tests, it will suffer most significant damage. Furthermore, , the outer receptacle and inner receptacle have flanges on their upper portion, and these flanges will be more affected by flames during the thermal test than the other portions. For these reasons, adopting the package orientation that will cause most significant damage to the upper corner was regarded as justifiable in the regulatory idea that the package should be damaged as much as possible in the drop tests as well as in the thermal tests which follow the drop tests. Thus, the thermal effects will be most visible on the package during the subsequent thermal test.
To determine possible considerations to be taken in relation to the subsequent criticality analysis, Prototype No. 1 was examined in several orientations in which the effects under test conditions were supposed to appear most visibly and in a composite manner, and the results of the examination will be utilized for the criticality evaluation.
Prototype No. 1 was subjected to examination tests in which it was dropped in various orientations to check that orientations with the corner facing downward cause maximum damage to the package. Prototype No. 2 was subjected to the main drop tests, solely with its corner facing downward.
In the preliminary examinations with Prototype No. 1, we decided to omit cases whose outcomes were not needed in terms of package performance and those which might be included by other more demanding cases.
Table II-A.App1-2 shows the adopted cases.
II - A.App1 - 14
Table II-A.App1-2: Examined Cases of Events for Prototype Packaging Prototype No.1 Test Item Prototype Remarks No.2 Effect of water spraying on the outer plates of stainless steel was Water spraying x x regarded as negligible.
Lid x Effect on the lid of the inner receptacle was checked.
Effect on the flange of the inner receptacle was regarded as negligible Horizontal Orientation because of the location and buffering effect of the legs. Located over Bottom x x skeletons, the legs are not likely to be dented. Even if they should be dented, causing cracks on the outer plate, the ceramic fiber insulator Normal Conditions of Transport A F will not be lost.
Narrower x Effect on the inner receptacle flange and the contents was checked.
Side 1.2 This case was omitted because no visible consequence will appear and m Wider Side x x the case with the narrower lateral side facing downward is more demanding (9 meter test is feasible).
Inclined at 30° Narrower This case was omitted because no visible consequence of rebound will x x Side appear (9 meter test is feasible).
This case was omitted because no visible consequence will appear and Wider Side x x the case with the narrower lateral side facing downward is more demanding This is the orientation of the package in which the flange of the outer Corner receptacle is expected to be most affected.
Compressive stresses in main steel elements are evaluated by 5 x Load x x calculation.
Several zones which appear most vulnerable were chosen on the Steel rod penetration x lateral sides and top surface, and tests were carried out with these zones facing downward.
Lid x Effects on the inner receptacle were checked.
Effect on the flange of the inner receptacle was regarded as negligible because of the location and buffering effect of the legs. Located over Horizontal Orientation Bottom x x skeletons, the legs are not likely to be dented. Even if they should be Accident Test Conditions of Transport F dented, causing cracks on the outer plate, the ceramic fiber insulator will not be lost.
Narrower x Effect on the inner receptacle flange and the contents was checked.
Side The case with the narrower lateral side facing downward is more 9
demanding, but the orientation of the pellet storage boxes differs m Wider Side x from the orientation of those located close to the narrower lateral sides.
Effect on the outer receptacle flange was checked. The specimen used Inclined at 30° Narrower for this test was not that used for the test with horizontal lid facing x
Side downward. This test was carried out with a corner at the opposite side facing downward.
This case was omitted since the case with the narrower lateral side Wider Side x x facing downward is more demanding.
Corner Effect on the outer receptacle flange was checked.
II - A.App1 - 15
Horizontal Orientation Near lid The impact point adopted for this test is located near the weld of a x
lifting attach. lifting attachment.
Center of This case was omitted since a test with the package inclined is more x x wider side demanding.
This test was carried out to check whether or not the zone around the Near leg x weld of the legs suffered cracking. (The presence of the legs made it impossible for the package to take an inclined orientation.)
Damage caused by the edge of the penetrating bar to the lifting Center of x attachment was checked. This case was regarded as most suitable for Penetrating Bar wider side producing the largest deformation in the outer plates.
Near lifting Damage caused by the edge of the penetrating bar to the zone near attach. on x Inclined the lifting attachment on the lid was checked.
wider side Flange on x Deformation in the flange was checked.
wider side This case was omitted because the impact point was located directly Corner of x x on the frames so that large deformations or large cracks were not narrower side likely to occur.
The impact point was located directly on the skeleton so that large deformations or large cracks were not likely to occur, but this Corner x orientation of package is optimal for damaging the flange. This case was adopted to check the effect of superposition.
Prototype No. 2 was used since larger amounts of heat were likely to Thermal test x enter the packaging. The definitive evaluation was made in the thermal analyses using a model.
This case was not necessary since the criticality evaluation will take 0.9-m water immersion x x water immersion into account.
- Tested for examination x: Not tested.
II - A.App1 - 16
For the 9-meter drop tests using Prototype No. 1, inclined package orientations other than horizontal and corner facing downward were adopted as well. These inclined orientations were adopted to check specific behavior of the package: rebounding following the first impact. Such behavior cannot be predicted exactly and it is difficult to find a suitable inclination for the specimen. As described in chapter II-A. Structural Analyses, section A.2. Weights and Center of Gravity, the center of gravity of the package is located almost in its geometrical center. Inclined drop tests are carried out with the package lid facing practically downward (refer to Fig. II-A.App1-8). Larger inclinations () are regarded as more demanding conditions. However, too large an inclination may involve absorption of impact energy by the deforming edge of the package. As shown in Fig. II-A.App1-8, when the package is inclined 45° in relation to the horizontal, the angle of the center of gravity exceeds 80° or becomes close to the vertical. For this reason, we decided to adopt an inclination of 30° (=68°) for the package orientation examination tests.
1134 446 Horizontal Inclined at 30° Inclined at 45° Fig. II-A.App1-8: Examination of Package Inclinations For the 1-meter drop onto penetrating bar tests, the IAEA document of Regulations for the Safe Transport of Radioactive Material, under the code TS-G-1.1, states that a tilted package may suffer greater damage in the 1-meter drop-onto-penetrating-bar test and recommends an inclination of 20° to 30° for the package. Long packages such as those consisting of a transport packaging for unirradiated nuclear fuel assembly are considered likely to present a behavior of inflection at the impact point under drop impact energy of both ends of the package after the collision onto the penetrating bar. Thus, smaller inclinations are expected to correspond to a more demanding drop condition because both ends strike the test target plate (or the penetrating bar) tardily. On the other hand, with box-shaped packages such as those consisting of the Type GP-01 transport packaging considered, greater inclinations are supposed to correspond to a more demanding drop condition: most of the drop impact energy is concentrated on the impact point. Thus, in our 1-meter penetrating bar tests, we decided to test the specimens in an inclined orientation (30°) in addition to horizontal orientation.
II - A.App1 - 17
Table II-A.App1-3 shows the sequence of the drop tests. To reduce the overall time for drop test processes, deformations were measured after all the tests were completed in four cases of 1.2-meter drop and steel rod drop.
Table II-A.App1-3: Sequence of Drop Tests Time Zone Specimen Case Designation Remarks 1.2-m drop in horizontal orientation with 1
the lid facing downward 1.2-m drop in horizontal orientation with AM 2 the narrower lateral side facing downward 1.2-m drop with the corner facing 3
downward (1.2-m corner drop)
Center of lateral 4 Steel rod penetration side, fusible plug First Day Visual appearance check, geometrical measurements 9-m drop in horizontal orientation with the 5
lid facing downward PM Visual appearance check, geometrical measurements 9-m drop in horizontal orientation with the 6
narrower lateral side facing downward Visual appearance check, geometrical measurements 9-m drop in horizontal orientation with the Prototype 7 wider lateral side facing downward No. 1 Visual appearance check, geometrical measurements 9-m drop in inclined orientation with the Orientation 8
AM narrower lateral side facing downward inclined at 30° Visual appearance check, geometrical measurements 9 9-m drop with the corner facing downward Second Day Visual appearance check, geometrical measurements 1-m drop in horizontal orientation with a 10 point near lifting attachment on the lid onto the penetrating bar 1-m drop in horizontal orientation with a 11 point near leg onto the penetrating bar PM 1-m drop in inclined orientation with a Orientation 12 point near lifting attachment on the wider inclined at 30° lateral side onto the penetrating bar Visual appearance check, geometrical measurements 1.2-m drop with the corner facing 13 Third Prototype downward (or other orientations)
Day AM No. 2 Visual appearance check, geometrical measurements II - A.App1 - 18
9-m drop with the corner facing downward 14 (or other orientations)
Visual appearance check, geometrical measurements 1-m drop in inclined orientation with the Orientation 15 center of the wider lateral side onto the inclined at 30° Prototype penetrating bar No. 1 1-m drop in inclined orientation with Orientation 16 flange on the wider lateral side onto the inclined at 30° penetrating bar PM 1-m drop in inclined orientation (or other Prototype 17 orientations) with the corner onto the No. 2 penetrating bar Prototypes Prototypes No. 1 Visual appearance check, geometrical No. 1 and - and No. 2 were measurements No. 2 inspected together.
Note: Geometrical measurements for the three 1.2-m drop tests of Prototype No. 1 were carried out together after all these three tests were completed.
3.4. Test Results (1) 1.2-m drop in horizontal orientation with the lid facing downward (case 1) (Photos A.App1-13 and A.App1-14)
The specimen, inverted upside down, was dropped, struck the test target and rebounded once, keeping its horizontal orientation. The specimen supported the impact load almost uniformly on its lid top. No local deformation occurred.
Checking the impact surface revealed no significant deformations. The geometrical measurements of the first three 1.2-meter drop tests revealed changes in dimensions of only 1 millimeter. No dents that might contain a 10-cm cube were generated on the package.
Table II-A.App1-4 shows the highest accelerations generated. The direction Y+ corresponding to the highest acceleration is identical to the package orientation. These data show that high accelerations did not occur in any of the other directions and that the specimens struck the test target with uniform impact energy.
Table II-A.App1-4: Highest Accelerations during 1.2-m Drop in Horizontal Orientation with Lid Facing Downward (case 1)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z
+ 26 202 33 53 430 53
- -23 -95 -48 -107 -126 -46 H E Z+ Z-X- Y-G F X+
D A Y+
C B II - A.App1 - 19
(2) 1.2-m drop in horizontal orientation with the narrower lateral side facing downward (case 2) (Photos A.App1-15 and A.App1-16)
The specimen did not keep its initial orientations until touchdown, and the lid-side portion rotated slightly so that it struck the test target with its edge CD first. Probably because of the insufficient drop height, the measurements revealed no significant deformations on the lid that might have been generated by the drop.
Deformations of 1 mm were observed on the body (all elements except for the lid) of the package. No dents that might contain a 10-cm cube were generated on the package.
Table II-A.App1-5 shows the highest accelerations generated. The highest acceleration (317 G) occurred in the drop (vertical) direction (Z+) in the outer receptacle. Upon occurrence of a high acceleration (183 G) in the direction Y+, a similar degree of acceleration (160 G) occurred in the opposite direction (Y-). Since the acceleration in direction Y- occurred with similar timing to that in the direction Z-, the former can probably be attributed to the vibration caused by the touchdown of the leg side opposite to the lid side which struck the test target first.
In the inner receptacle, a high acceleration (83 G) was recorded in the drop direction (Z+). The highest value (157 G) was observed for the direction Y+. Since the inner receptacle was not fixed in the outer receptacle, the mass of the inner receptacle swung in the direction Y+ and struck the inner wall of the outer receptacle hard after the lid-side portion struck the test target.
Table II-A.App1-5: Highest Accelerations during 1.2-m Drop in Horizontal Orientation with Narrower Lateral Side Facing Downward (Case 2)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 14 157 83 132 183 317
-14 -95 -32 -43 -160 -89 B F Y+ Y-A E Z-X+
X-Z+
C G
D H (3) 1.2-m drop with the corner facing downward (case 3) (Photos A.App1-17 to A.App1-19)
The specimen struck the test target, rebounded once and landed with the same corner for a second touchdown, and then fell down on its lid. Thus, all the energies were almost concentrated on the corner. A significant deformation was observed on the lifting attachment near the corner. No deformations were generated on the other portions including the rod bolts. Deformation that might have caused the flange to open did not occur. No dents that might contain a 10-cm cube were generated on the package.
Table II-A.App1-6 shows the highest accelerations generated No accelerations in the direction identical to the II - A.App1 - 20
drop direction were measured so that excessive accelerations did not occur in this case. Every simple sum of the accelerations in the three directions is smaller than 100 G and any of those recorded in the preceding cases.
This may be attributed to the deformed corner which absorbed much of the impact energy.
Table II-A.App1-6: Highest Accelerations during 1.2-m Drop with Corner Facing Downward (Case 3)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 16 60 59 6 46 71
-42 -24 -26 -35 -14 -16 F Y- Z-Y+ X+
B X- Z+
A G H
D Table II-A.App1-7 shows the geometrical measurements of the package which underwent the first three 1.2-meter drop tests. The deformations observed during these tests were insignificant (1 to 2 mm) in all the cases except those of corner drop or drop with the corner facing downward.
The volume reduction was calculated by regarding the package (820 x 1134 x 920 mm) as a rectangular cuboid while the legs, the fusible plug, the fork guard and the portions of the lifting attachments which protrude from the flash surfaces of the packaging were ignored. On the assumption that the wider lateral side uniformly deformed by 2 mm, a 0.24 percent reduction was obtained in the volume of the entire package.
In case 3 (1.2-m drop with the corner facing downward), the stainless steel plates which comprise the lifting attachment were deformed, but only a small reduction was observed in the volume of the body of the packaging. In this 160 case also, the package was regarded for calculation as a rectangular cuboid. On 140 156 the assumption that the corner was crushed in such a way that a three-sided pyramid (whose triangular bottom is delimited by the roots of the lifting (mm) attachment and the flange corner) was lost in volume, a reduction of 0.14 percent was obtained.
II - A.App1 - 21
Table II-A.App1-7: Dimensional Measurements: 1.2-m Drop with Corner Facing Downward (Case 3)
(Unit: mm)
Before After Edge Deformation Remarks Test Test AD 1142 1138 4 No deformations during corner drops and no Lid significant effect during the length BC 1143 1143 0 drop with the narrower side facing downward Lid AB 828 828 0 No effect width CD 829 830 -1 AE 1057 1058 -1 Only insignificant effects of BF 1059 1058 1 drops with the lid facing CG 1061 1060 1 downward (deformations).
Height Deformations generated by a DH 1061 1055 6 drop with the corner facing downward AD 1132 1 Only insignificant effects of 1133 Body EH 1132 1 drops with the narrower side length BC 1133 1 facing downward 1134 FG 1133 1 (deformations)
AB 819 2 821 Only insignificant effects of Body EF 820 1 the preceding tests width CD 819 1 820 (deformations)
GH 820 0 a 34 Lifting attachment deformed b 40 by a drop with the corner c 17 facing downward
- d (93) 68 24 C B B A c D A d a
Viewed from above G F Viewed from lateral side b
C D H E (4) Steel rod penetration (case 4) (Photos A.App1-20 to A.App1-22)
A steel rod is released in the vertical orientation from a height of one meter onto several points on the package: the central zone (not supported by any part of the frames), a rod bolt, the fusible plug and several zones of different strengths. Small dents (1 to 2 mm in depth) were caused on the external surface, but no significant damage was observed.
(5) 9-m drop in horizontal orientation with the lid facing downward (case 5) (Photos A.App1-23 to A.App1-26)
The specimen did not keep its initial orientation until touchdown so that it struck the test target plate with its edge CD first. The specimen rebounded once. After the first touchdown, the specimen did not rotate. This behavior was attributed to the lower rigidity of the edge of the lid which absorbed the touchdown impact of II - A.App1 - 22
the package on the test target plate. The high-speed camera recorded a deformation of a zone near the bolt seat on the external surface when the edge CD struck the test target. A visual check after the test revealed a bulge-like deformation on the external surface of this zone. Measurements of the height dimension of the package showed an effect of the non-horizontal touchdown of the package. Moreover, a slight deflection of up to 3 mm was observed on the external plate of the lid in this zone corresponding to a void between frames.
None of the rod bolts became loose or fell off. Table II-A.App1-8 shows the measurements of the package before and after the test.
Table II-A.App1-9 shows the highest accelerations generated in three directions of the inner and outer receptacle. The highest value (929 G) of these accelerations was recorded for the direction Y+ or drop direction. A fairly high acceleration (186 G) occurred in the direction Z+ and can probably be attributed to the non-horizontal touchdown of the package.
In the inner receptacle, the highest value (296 G) was recorded for the direction Y+ which corresponded to the orientation of the package. No significant impact force was generated in the direction Z+ when the package struck the test target in the altered horizontal orientation.
Table II-A.App1-8: Dimensional Measurements: 9-m Drop in Horizontal Orientation With Lid Facing Downward (Case 5)
(Unit: mm)
Before After Edge Deformation Remarks Test Test AD 1138 1139 -1 Insignificant deformations Lid length attributed to the non-horizontal BC 1143 1144 -1 touchdown of the package AB 828 828 0 Lid width No effect of drop CD 830 829 1 AE 1058 1056 2 BF 1058 1055 3 Visible effects of the non-Height CG 1060 1050 10 horizontal touchdown DH 1055 1033 22 AD 1132 1134 -2 Insignificant deformations Body EH 1132 1134 -2 attributed to the non-horizontal length BC 1133 1133 0 touchdown of the package FG 1133 1133 0 AB 819 820 -1 Body EF 820 819 1 No significant deformations.
width CD 819 820 -1 GH 820 820 0
- Bulge near the bolt seat on the
- a - 12 external surface a C B C D D A G F G H H E II - A.App1 - 23
Table II-A.App1-9: Highest Accelerations during 9-m Drop in Horizontal Orientation with Lid Facing Downward (Case 5)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 63 296 50 27 929 186
-18 -65 -48 -48 -300 -122 H E Z+ Z-X- Y-G F A X+
D Y+
C B (6) 9-m drop in horizontal orientation with the narrower lateral side facing downward (case 6) (Photos A.App1-27 to A.App1-29)
The specimen did not keep its initial orientations until touchdown so that it struck the test target with its edge CD first. Accordingly, the specimen behaved as if the packaging had been pushed aside in the horizontal direction on the test target plate. The high-speed camera recorded a slight deformation of the external plate of the package at the touchdown. A visual check on the drop test revealed no excessive deformations. Only small bulges were observed on the lid and body. Geometrical measurements revealed deformations of 7 to 17 mm of the length of the lid which struck first the test target and deformations of 5 to 6 mm of the body of the packaging in a location close to the lid. Table II-A.App1-10 shows geometrical measurements of the package before and after the test.
A slight deflection or bulge was observed on the external plate of the lid at a location corresponding to a void between frames. None of the rod bolts became loose or fell off. No significant local deformation occurred.
Table II-A.App1-11 shows the highest accelerations generated. The specimen struck the test target in a similar way to the 1.2-meter drop in the same orientation. Therefore, the accelerations recorded are comparable with those recorded in the 1.2-meter drops. The outer receptacle presented the highest value (635 G) for the direction Z+ and a high acceleration (535 G) for the direction Y+ as well (another similarity to the 1.2-m drops in the same orientation). The inner receptacle showed a far higher acceleration in the direction Y+ than in the direction Z+ which was the drop direction. This difference can probably be attributed to the fact that the inner receptacle was not fixed in the outer receptacle. As a result, the mass of the inner receptacle struck the inner wall of the outer receptacle very hard at the moment of the non-horizontal touchdown of the package.
II - A.App1 - 24
Table II-A.App1-10: Dimensional Measurements: 9-m Drop in Horizontal Orientation with Narrower Lateral Side Facing Downward (Case 6)
(Unit: mm)
Before After Edge Deformation Remarks Test Test AD 1139 1132 7 Visible effects of the non-Lid horizontal (lid first) length BC 1144 1127 17 touchdown Lid AB 828 829 -1 No effect of drops width CD 829 829 0 AE 1056 1056 0 BF 1055 1057 -2 Insignificant bulges caused Height CG 1050 1051 -1 probably by the drops DH 1033 1035 -2 AD 1134 1129 5 Body EH 1134 1133 1 Some effects of the non-length BC 1133 1127 6 horizontal touchdown FG 1133 1132 1 AB 820 820 0 Body EF 819 820 -1 No significant deformation width CD 820 820 0 GH 820 820 0 Bulges on the lid top
- b - - 14 surface
- c - - 12 Bulges provoked on the external surface near the
- d - - 12 bolt seats of the packaging C B B C A D D A b c Impact surface Impact surface G F F G B d H E C Table II-A.App1-11: Highest Accelerations during Drop in Horizontal Orientation with Narrower Lateral Side Facing Downward (Case 6)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 62 422 225 102 535 635
-69 -100 -48 -69 -313 -154 B F Y+ Y-A E Z-X+
X-Z+
C G
D H II - A.App1 - 25
(7) 9-m drop in horizontal orientation with the wider lateral side facing downward (case 7) (Photo A.App1-30)
The high-speed camera recorded the drop behavior of the specimen keeping its initial horizontal orientation.
Measurements of the major dimensions of the package revealed deformations on the lid and a portion of the body near the lid, and no deformation on the remaining portions of the package. These results suggest that the package struck the test target with its lid side first (though the pictures taken do not show the behavior of the package clearly because of its location). None of the rod bolts became loose or fell off. No significant local deformation occurred. Several bulges were produced on the external surface of the lid. Table II-A.App1-12 shows geometrical measurements of the package before and after the test.
Table II-A.App1-13 shows the highest accelerations generated. In the outer receptacle, the highest value (937 G) was recorded for the drop direction (X+) but this acceleration was accompanied by another (193 G) in the direction Y+. These phenomena suggest that the package struck the test target with its lid side first. In the inner receptacle, the highest value (301 G) was recorded for the drop direction (X+).
Table II-A.App1-12: Dimensional Measurements: 9-m Drop in Horizontal Orientation with Wider Lateral Side Facing Downward (Case 7)
(Unit: mm)
Before After Edge Deformation Remarks Test Test AD 1132 1132 0 The deformations generated during the Lid preceding narrower lateral length BC 1127 1132 -5 side horizontal orientation drop were partly canceled.
Lid AB 829 820 9 Larger deformation than in width CD 829 823 6 the body of package AE 1056 1057 -1 BF 1057 1057 0 Height No significant deformation CG 1051 1052 -1 DH 1035 1034 1 AD 1129 1129 0 The deformations EH 1133 1134 -1 generated during the Body BC 1127 1130 -3 preceding narrower lateral length side horizontal orientation FG 1132 1133 -1 drop were partly canceled.
AB 820 816 4 Body EF 820 820 0 Deformation in the lid-side width CD 820 817 3 portion of the body GH 820 820 0
- e - - 15
- f - - 10 Bulges on the lid surface
- g - - 12 C B B C B D A A e,f,g f g e
D A Impact surface G F Impact surface F
H E E F H E II - A.App1 - 26
Table II-A.App1: Highest Accelerations during 9-m Drop in Horizontal Orientation with Wider Lateral Side Facing Downward (Case 7)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 301 119 101 937 193 80
-56 -47 -106 -177 -110 -197 D A Z+ Z-H E Y+ X-C Y-B F X+
G (8) 9-m drop in inclined orientation with the narrower lateral side facing downward (case 8) (Photos A.App1-31 to A.App1-34)
This test was carried out to check the consequences of a rebound after touchdown of the package in which it kept its initial inclined orientation. Since the edge of the packaging lid had only low rigidity, the edge AB absorbed part of the impact force while deforming to a certain degree. Thus, the package showed the behavior of sliding aside on the test target plate, and the rebound was not so strong as expected. Results of the dimensional measurements revealed that the deformation of the corner B was larger than that of the corner A. The pictures taken with the high-speed camera showed a simultaneous touchdown of both corners.
It was supposed that a part of the honeycomb elements behind the plane BCGF had already been deformed in such a way that a void was created in the preceding test (9-m drop in horizontal orientation with the wider lateral side facing downward). Thus, the inner receptacle moved in the outer receptacle and produced a larger load on the corner B than on the corner A at touchdown of the package, thus increasing the deformation in the corner B. Cracking occurred in the joint between the lifting attachment at the corner B and the external surface so that the insulator was exposed but not lost. None of the rod bolts became loose or fell off. Table II-A.App1-14 shows measurements of the major dimensions of the package before and after the test.
Table II-A.App1-15 shows the highest accelerations generated. In the outer receptacle, an acceleration of 290 G occurred in the direction Y+ and an acceleration of -181G in the direction Z- at the moment of the first touchdown of the package. At the second touchdown (0.03 seconds after the first), an acceleration of -154 G occurred in the direction Y- and an acceleration of 217 G in the direction Z+. The rebound did not appear to be so hard in the pictures taken with the camera but was found to have produced a hard impact due to the accelerations in the outer receptacle. In the inner receptacle, an acceleration of 269 G occurred in the direction Y+ and an acceleration of -170 G in the direction Z- at the first touchdown. At the second touchdown, high accelerations occurred though the outer receptacle presented a slightly delayed behavior.
II - A.App1 - 27
Table II-A.App1-14: Dimensional Measurements: 9-m Drop in Inclined Orientation with Narrower Lateral Side Facing Downward (Case 8)
(Unit: mm)
Before After Edge Deformation Remarks Test Test AD 1132 1134 -2 Deformations of the edge Lid caused small increase or length BC 1132 1131 1 decrease in dimension.
AB 820 831 -11 The lid edge was crushed Lid and expanded in the radial width CD 823 823 0 direction.
AE 1057 1049 8 Deformations which BF 1057 1000 57 Height suggest concentration of CG 1052 1044 8 load on the corner B DH 1034 1034 0 AD 1130 1129 0 Body EH 1133 1133 1 length BC 1129 1130 0 Serious deformations FG 1134 1133 0 occurred in the lid. No AB 817 817 -1 significant changes in the Body EF 820 821 -1 body.
width CD 816 818 -1 GH 820 820 0
- h 1041 - Heights of the affected
- i 1030 - lateral sides after deformation of the edge
- j (1060) 1012 -
AB Height of the central zone
- k 1071 -
of the package deformed
- l 83 10
- m (93) 76 17 Lid edge crushed
- n 35 58 C
C B B D A D A j l~n i
G F h View from k E H lateral side H E II - A.App1 - 28
Table II-A.App1-15: Highest Accelerations during 9-m Drop in Inclined Orientation with Narrower Lateral Side Facing Downward (Case 8)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 97 269 114 61 290 217
-65 -59 -170 -57 -154 -181 H
Z+
G E Z-F X-D X+ Y-C A Y+
B (9) 9-m drop with the corner facing downward (case 9) (Photos A.App1-35 to A.App1-37)
To generate an effect of superposition, the specimen was released for this test in the orientation adopted for the preceding 1.2-meter drop tests with the corner facing downward to strike consecutively the steel plate with the same impact point (its corner D). The specimen struck the test target, rebounded and landed on its opposite corner C for a second touchdown, and then fell down on its side.
A deformation was observed in the flange. However, no openings that might form routes for entry of flames were generated in the package. This deformation affected the bolt seat, but none of the rod bolts fell off or were broken.
Small cracks were found on the weld on the corner joint of outer plates under the flange near the deformation, but no portions of the insulator were lost. Cracking occurred in the weld between the deformed lifting attachment and the outer plate of the lid to the extent that the insulator became exposed, but no portions of the insulator were lost. Table II-A.App1-16 shows measurements of the package before and after the test.
Table II-A.App1-17 shows the highest accelerations generated. Accelerations were measured for the three directions of the inner and outer receptacle. No measurement was carried out for the direction identical to the drop direction. This decision is justified since the highest accelerations recorded in the outer receptacle and the inner receptacle for the three directions were facing practically downward. The inner receptacle presented higher accelerations than the outer receptacle. This was probably not because the honeycomb elements lost their buffering capability in the course of repeated drop tests, but because the inner receptacle, which is not fixed in the outer receptacle, struck the interior of outer receptacle hard. This supposition is supported by the fact that during the 9-meter drop with the corner facing downward test, Prototype No. 2 (the buffering capability of which is supposed to remain intact) presented higher accelerations in the inner receptacle than in the outer receptacle (described later).
II - A.App1 - 29
Table II-A.App1-16: Dimensional Measurements: 9-m Drop with Corner Facing Downward (Case 9)
(Unit: mm)
Before After Edge Deformation Remarks Test Test Lid AD 1134 length BC 1131 Lid AB 831 width CD 823 AE 1049 1049 0 BF 1000 1000 0 Height Deformation of the corner CG 1044 1049 -5 DH 1034 969 65 AD 1130 1153 -24 Body EH 1133 1134 -1 length BC 1129 1130 0 Bulge on the packaging FG 1133 1133 0 body caused by the AB 818 817 0 deformation of the corner Body EF 820 819 2 width CD 817 845 -27 GH 821 820 0 o 300 p 260 Deformation in the corner q 220 s 18 Bulge on the packaging t 22 body u 20 B o A s r q t C p D A D View E from B above C G H Table II-A.App1-17: Highest Accelerations during 9-m Drop with Corner Facing Downward (Case 9)
(Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 10 259 147 30 107 167
-152 -29 -45 -181 -48 -49 Y- Z-Y+ X+
X- Z+
F B
A G H
D II - A.App1 - 30
(10) 1-m drops in various orientations onto penetrating bar (cases 10, 11, 12, 15, and 16) (Photos A.App1-38 to A.App1-44, A.App1-52 to A.App1-55)
The top end of the penetrating bar used for these tests is flat as specified by the Regulations. The specimen was released in its horizontal orientation and an inclined (30 degrees) orientation in order to allow sufficient penetration of the bar into the package. The minimum required height for the bar was 200 mm. To increase potential damage to the contents, 450 mm was adopted.
Five cases were implemented . Adopted as impact points were the zone near the lifting attachment (case 10) and the zone near a leg (case 11) in horizontal orientations to check cracking in the welds, the central zone on a wider side (case 15) in an inclined orientation that was supposed to concentrate the impact load and provoke the deepest penetration into the specimen, and the zone near the lifting attachment on a wider side (case 12) and the flange on a wider side (case 16) in inclined orientations to check the openability of the lid.
In each case, the penetrating bar did not penetrate the outer plate of the outer receptacle. The deepest dent was caused in the central zone on a wider side during a drop in an inclined orientation (case 15), but no penetration occurred in this case either. In the case 12, the weld on the edge of the lid presented cracking resulting from a deformation. Nevertheless, no portion of the insulator was lost since this impact zone was not filled with insulator. Table II-A.App1-18 shows alterations in dimension suffered by the package tested.
Table II-A.App1-19 shows measured accelerations as informative data.
Table II-A.App1-18: Deformations during 1-m Drop onto Penetrating Bar (Unit: mm)
Deformation Remarks Zone near lifting 14 attachment on the lid Zone near a leg 28 Zone near lifting 14 attachment on wider side Central zone on wider 55 side Flange on wider side 11 Depth of dent on the flange: 4 mm II - A.App1 - 31
Table II-A.App1-19: Highest Accelerations during 1-m Drop Onto Penetrating Bar (Unit: G)
Inner Receptacle Outer Receptacle Case Direction Direction Direction Direction Direction Direction X Y Z X Y Z 1-m drop in horizontal 16 202 40 5 91 1 orientation with a point near lifting attachment on lid onto the penetrating bar -46 -78 -41 -19 -8 -23 (case 10) 1-m drop in horizontal 17 29 45 15 36 3 orientation with a point near leg onto the -10 -64 -33 -1 -56 -5 penetrating bar (case 11) 1-m drop in inclined 28 17 35 18 11 3 orientation with a point near lifting attachment on wider lateral side onto the -47 -42 -67 -17 -18 -12 penetrating bar (case 12) 1-m drop in inclined 3 20 20 3 9 2 orientation with the center of wider lateral side onto the penetrating bar (case -25 -15 -22 -37 -4 -5 15) 1-m drop in inclined 14 42 58 32 44 20 orientation with flange on wider lateral side on to -78 -39 -48 -116 -33 -41 penetrating bar (case 16)
Note: The accelerations shown in this table were recorded as informative data.
(11) 1.2-m drop with the corner facing downward (case 13) (Photos A.App1-45 and A.App1-46)
Prototype No. 2 was subjected to this test. The behavior of the specimen was similar to that of Prototype No.
1: it rebounded slightly after its first touchdown and struck the test target again on its corner and ceased to move on its lid. The lifting attachment on the corner showed significant deformation, but no deformation occurred in the other elements (including the rod bolts) of the package and no opening was produced in the flange. A difference from the outcome of Prototype No. 1 in other tests was that Prototype No. 2 suffered smaller deformation. Table II-A.App1-20 shows measurements of the package before and after the test.
The stainless steel plates comprising the lifting attachment were deformed 160 (similar results to case 3). Only a small reduction was observed in the package 140 volume. For the purpose of calculation, the package was regarded as a 156 rectangular cuboid. On the assumption that the corner was crushed in such a mm way that a three-sided pyramid (whose triangular bottom is delimited by the roots of the lifting attachment and the flange corner) was lost in volume, a reduction of 0.13 percent was obtained.
Table II-A.App1-21 shows the highest accelerations generated. As no measurement was carried out for the direction identical to the drop direction, the values recorded were not excessive. Similarly to Prototype No. 1 in this case, the specimen presented lower accelerations in the three directions than in the other two cases.
This was probably because the corner was deformed while absorbing much of the impact energy.
II - A.App1 - 32
Table II-A.App1-20: Dimensional Measurements: 1.2-m Drop with Corner Facing Downward (Unit: mm)
Before After Edge Deformation Remarks Test Test Lid AD 1142 1142 0 length BC 1143 1105 38 Lid AB 828 829 -1 width CD 829 820 9 Deformation of the corner AE 1058 1057 0 BF 1058 1056 3 Height CG 1059 1040 21 DH 1061 1057 4 AD 1132 1 1131 Body EH 1133 0 length BC 1133 1 1132 FG 1133 1 Deformations are not AB 820 1 significant.
819 Body EF 820 1 width CD 819 1 820 GH 820 0 a 24 b 36 Deformations of the lifting c 20 attachment d 93 77 26 C B D A B A c d
a G F View from View b above from the H E C D side Table II-A.App1-21: Highest Accelerations during 1.2-m Drop with Corner Facing Downward (Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 40 43 75 23 40 46
-8 -16 -16 -6 -8 -5 Z- Y-X- Y+
Z+ X+
E A
H B G
C II - A.App1 - 33
(12) 9-m drop with the corner facing downward (case 14) (Photos A.App1-47 to A.App1-49)
The specimen (Prototype No. 2) was released from a height of 9 meters to strike the test target with its corner C first in order to produce an effect of superposition. Following the first touchdown, the specimen rotated slightly to strike the test target with its corner B and then rotated again and ceased to move on its face behind which accelerometers were installed. Deformation affected the flange. However, no openings that might form routes for entry of flames were generated in the package. This deformation affected the bolt seat, but none of the rod bolts fell off or were broken.
Similarly to Prototype No. 1, cracking occurred in the weld of the deformed lifting attachment on the outer plate to the extent that the insulator became exposed, and no portions of the insulator were lost. Table II-A.App1-22 shows measurements of the package before and after the test.
Table II-A.App1-23 shows the highest accelerations generated No measurement was carried out for the direction identical to the drop direction. This decision is justified since the highest accelerations recorded in the outer receptacle and the inner receptacle for the three directions were facing practically downward.
Similarly to Prototype No. 1, the inner receptacle of Prototype No. 2 presented higher accelerations than the outer receptacle. These measurements suggest that the inner receptacle struck the interior of the outer receptacle hard.
The waveforms recorded show that a peak of acceleration produced at the same moment in the three directions in the outer receptacle was followed by a short reduction in acceleration and another series of high accelerations. The similar behavior observed in Prototypes No. 2 and No. 1 may be attributed to a buffering effect of the crushed corner zone of the package.
II - A.App1 - 34
Table II-A.App1-22: Dimensional Measurements: 9-m Drop with Corner Facing Downward (Unit: mm)
Before After Edge Deformation Remarks Test Test Lid AD 1142 1142 0 length BC 1105 1040 65 Lid AB 829 829 0 width CD 820 770 50 Deformation of the corner AE 1057 1055 2 BF 1056 1055 1 Height CG 1040 966 74 DH 1057 1058 -1 AD 1132 1132 0 Body EH 1133 1133 0 length BC 1133 1130 3 FG 1133 1132 1 Deformations are not AB 820 820 0 significant.
Body EF 820 820 0 width CD 819 818 1 GH 820 820 0 e 220 f 300 Deformations of the lifting g 180 attachment h 12 i 18 f
C B A D D A B e A D g View from B above C G F h H
H E F G i
II - A.App1 - 35
Table II-A.App1-23: Highest Accelerations during 9-m Drop with Corner Facing Downward (Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 80 104 152 78 68 107
-9 -9 -39 -23 -16 -6 Z- Y-X- Y+
Z+ X+
E A
H B G
C (13) 1-m drop with the corner facing downward onto penetrating bar (case 17) (Photos A.App1-50 and A.App1-51)
The specimen was released from a height of one meter to strike the penetrating bar with its corner C first in order to produce an effect of superposition. Following the first touchdown, the specimen rotated smoothly and slightly, and then ceased to move on its face behind which accelerometers were installed.
This test was carried out after the specimen suffered impact loads during the 1.2-meter and 9-meter drop tests on its same impact point. No deep dents were produced. The cumulative dents on the affected zone measured 4 to 7 mm.
Table II-A.App1-24 shows the highest accelerations generated. In this test, accelerations were measured for informative purposes. The highest values of acceleration were generally high despite the drop height (refer to the measurements recorded during the preceding 9-meter drop test). This was probably because the zone had been deformed during the preceding two test cases and had lost much of its buffering capability.
Table II-A.App1-24: Highest Accelerations during 1-m Drop with Corner onto Penetrating Bar (Unit: G)
Inner Receptacle Outer Receptacle Direction Direction Direction Direction Direction Direction X Y Z X Y Z 38 92 101 30 141 85
-27 -43 -17 -26 -37 -26 E
A H B Z- Y-G X- Y+
Z+ X+
C II - A.App1 - 36
- 4. Inspections after Tests When these tests had been completed, Prototypes No. 1 and No. 2 were opened at the facility of Sakaguchi, Manufacturing, the manufacturing company of these prototypes, and at the facility of NFI Kumatori Branch to inspect their interiors.
4.1. Prototype No. 1 (1) The honeycomb elements on the back of the lid of the outer receptacle were deformed and totally separated from the lid. Many of the honeycomb elements on the lateral sides of the outer receptacle were separated from their neighboring components of the packaging. Some of the aluminum plates on the honeycomb elements had also peeled off, or almost so, from the elements. Some solidified fragments of the adhesive for honeycomb element had been scattered around on the inner receptacle (Photos A.App1-56 to A.App1-58).
(2) The back of the outer receptacle presents dents and penetration holes which were probably produced by the same rod bolts during collisions in different test cases.
(3) Penetration holes were found mainly along the edges AB and DA. The penetration holes and dents along the edge AB suggest that rod bolts had struck the back of the lid of the outer receptacle hard. The drop with the horizontal narrower side CDHG facing downward caused dents that were somewhat closer to this side.
The honeycomb elements which peeled off have no penetration holes and the surface to which these honeycomb elements had been applied suffered penetration holes. An interpretation of all these results suggests that these holes were probably created after the honeycomb elements on the back of the lid of the outer receptacle were separated from the lid and the honeycomb elements on the face CDHG were deformed under compressive load: after the drop in horizontal orientation with the narrower side facing downward (Photos A.App1-59 to A.App1-62).
Lid of outer receptacle C B D A Narrower side which was made to strike the penetrating bar in G F its horizontal orientation H E (4) A dent was produced at the corner on the back of the lid of the outer receptacle, probably resulting from a collision with the flange of the inner receptacle during corner drop tests. The deformations during the corner drop tests did not affect the package so deeply as estimated from outside. As a result of crushing, the edge of the lid of the outer receptacle must have increased the buffering capability of the packaging (Photo A.App1-62).
Judging from their locations, other dents were obviously created during the tests in which the narrower and wider sides were made to suffer the impact force first. There are no significant traces indicating that they occurred during drop tests inn the horizontal orientation with lid facing downward.
II - A.App1 - 37
(5) Scratches were found on the back of the lid of the outer receptacle, close to the surface CDHG. They may have been caused by some of the rod bolts during the drop with the horizontal narrower side facing downward. Impact damage which can be attributed to a collision with the frame of the lid of the outer receptacle was found on the heads of the rod bolts in the inner receptacle (Photos A.App1-63 to A.App1-65).
(6) An effect of superposition of the various consecutive 9-meter drop tests contributed in some degree to the dents and penetration holes caused by rod bolts on the back of the lid of the outer receptacle. In an individual (independent) case of event, such damage would not have occurred or would have been less serious thanks to the buffering capability of the honeycomb elements on the back of the lid.
(7) The original distance (175.6 mm) from the surface of the honeycomb elements to the external surface of the outer receptacle was reduced to 136 mm on the wider side of the package and 129 mm on the narrower side. This dimensional reduction is a result of the deformation in the inner surface of the outer receptacle, the protective rectangular pipe for inner receptacle flange and the honeycomb elements. The distance includes a 6 mm portion of the deformed honeycomb element and the aluminum plate on the rectangular pipe. Thus, since some portions of the honeycomb elements peeled off, the shortest distance from the external surface of the outer receptacle to the external surface of the inner receptacle is 130 mm on the wider side and 123 mm on the narrower side (Photo A.App1-66).
Before Tests After Tests Outer Outer Honeycomb element receptacl receptacle Rectangular pipe e (8) A drop with the horizontal lateral side facing downward caused deformation in the protective rectangular pipe for inner receptacle flange on the inner surface of the lateral side of the outer receptacle (more visible deformation on the narrower side) and left traces of collision of the inner receptacle flange on the inner surface of the outer receptacle. The flange of the inner receptacle suffered some dents but underwent no significant deformations that might have been caused by a collision with the inner surface of a lateral side of the outer receptacle.
Some traces of collision with the heads of the rod bolts were found on the upper zone of a lateral side of the outer receptacle. None of the rod bolts were broken during this collision (Photos A.App1-67 to A.App1-69).
(9) The inner receptacle lid bar presents traces of a collision with the frames of the outer receptacle lid which might have occurred during a drop with the narrower side facing downward or during a drop in inclined orientation (Photo A.App1-70).
(10) The inner receptacle lid bar presents a waveform deformation which was probably produced during a drop with the horizontal or inclined lid facing downward. The central zone of the lid of the inner receptacle II - A.App1 - 38
swelled. The heads of several rod bolts located near the lid center were bent as if they had been drawn by the deformation (Photo A.App1-71).
(11) The corner of the inner receptacle that was made to suffer the impact force first in a drop test presented a slightly bent shape. This was because during the preceding tests, the honeycomb elements and the flange protection pipe had lost their buffering capability (Photo A.App1-69).
(12) The bolt seat struck the inner surface of the frame in the outer receptacle and was drawn and enlarged.
This deformation was probably caused during a drop test with the package corner facing downward. The rod bolt remained in place (Photo A.App1-72).
(13) The narrower side of the inner receptacle which was made to suffer the impact force first in the horizontal orientation showed swelling of its lower zone 6 mm in height (Photo A.App1-73).
(14) The plates simulating the boronic stainless steel plates on the inner surfaces of the inner receptacle remained in their initial orientations and suffered no significant damage or deformation. Regardless of the surface of the package selected for first touchdown in the drop tests, these plates are installed in the very limited space between the pellet storage box assemblies and the inner receptacle. Therefore, even if they should be separated from their specified orientations, they would not leave their effective zones (Photo A.App1-74).
(15) All the fixing blocks were broken on the plate simulating the double boronic stainless steel plate located between two pellet storage box assemblies in the center of the inner receptacle. One of the halves of the plate rose 8 mm from the other half. This was not a significant displacement and no significant displacement occurred in the double plate. The broken fixing blocks caused some deformation in the plate. Both ends of the plate were bent slightly under the compressive force of the pellet storage box assemblies. No cracking occurred. Thus, the package maintained its integrity (Photos A.App1-75 to A.App1-77).
(16) The pellet storage box assembly 1 located near the surface CDHG facing Assembly 1 Assembly 2 downward in horizontal drop and corner drop tests did not keep its integrity:
After being retrieved from the inner receptacle, it stands in slightly inclined posture.
Deformation occurred but there was no cracking or fracture in any of the uppermost, C B D A intermediate or lowermost partitions which simulate boronic stainless steel plates.
The inclination of the posture can be attributed to the deformed partitions. Far less G F serious deformations occurred in the other pellet storage box assembly and in the H E partitions (Photos A.App1-78 and A.App1-79).
(17) The pellet storage boxes stacked in the assemblies present no opening resulting from damage. They kept their shape and capabilities. The lead rods simulating the weight of fuel did not come out and were not exposed (Photos A.App1-78 and A.App1-79).
II - A.App1 - 39
(18) The set of partitions (thickness: 3 mm) in assembly 1 presents a deflection, probably because of an impact from beneath. The fourth (counted from top) partition presents the largest deflection (13 mm). The uppermost and lowermost partition 5 mm in thickness present smaller changes of shape. Larger deformations were found rather on the side of the surface CDHG. None of the partitions was broken (Photo A.App1-78).
(19) A set of partitions of the pellet storage box assembly 1 showed slight swelling on its top. This deformation is smaller than that observed in the assembly 1 (Photo A.App1-79).
(20) None of the nuts on the pillars of the pellet storage box assemblies became loose. However, despite the sound appearance, the nuts could not be manually loosened for removal. They must have been deformed under an impact load of the lid of the inner receptacle at the moment of hard touchdown of the package on the test target and/or the penetrating bar.
(21) The pellet storage box assemblies were dismantled and all the partitions were inspected. No deformations or cracks that might have reduced the effective surfaces of boronic stainless steel plates were found (Photo A.App1-80).
(22) The rubber blocks for positioning pellet storage boxes were not broken. No significant deformations were found in the rod bolts which had fixed these rubber blocks (Photo A.App1-80).
(23) The pellet storage boxes were inspected. Some of them were slightly deformed under the load of the deformations in the partitions. No fracture, crack or cleft was produced in the boxes which well retained the entire contents (lead rods) (Photos A.App1-81 to A.App1-83).
(24) The interiors of the pellet storage boxes were inspected. None of the lead rods simulating the weight of fuel elements was separated from the waveform plates. The positioning bosses for the waveform plates at the four corners of the storage box were considerably deformed (obviously during a drop in horizontal orientation with the wider side facing downward) (Photos A.App1-84 to A.App1-87).
(25) The heads of the pillars in the pellet storage box assembly were deformed so that the nuts could not be loosened for removal. However, no significant deformations were caused. No significant deformations or fractures were produced in the fixing blocks for retaining the partitions in place. The required space between two partitions was maintained (Photos A.App1-78 and A.App1-79).
(26) The drop with the corner facing downward was the last case for Prototype No. 1. Therefore, this prototype was supposed to have already suffered deformations in the honeycomb elements and protective pipe for the inner receptacle flange before the last test. The inner receptacle of Prototype No. 2 suffered no deformation.
II - A.App1 - 40
4.2. Prototype No. 2 (1) The rod bolts in the outer receptacle were not broken in the course of the tests. Since the outer receptacle was deformed, some of the rod bolts could not be loosened for removal. Some bolts and nuts were loosened and removed in the normal way and some affected bolts were cut to open the lid of the outer receptacle.
(2) One (the lower on the inner receptacle side) of the two stages of honeycomb elements on the back of the outer receptacle lid was separated from the lid completely. It was probably pushed hard by the bar on the lid of the inner receptacle. The other honeycomb elements were not separated from their respective zones of the outer receptacle. Some fragments of the solidified adhesive were found scattered around on the surface of the inner receptacle (Photos A.App1-88, A.App1-90 and A.App1-91).
(3) The honeycomb elements on the back of the outer receptacle were slightly deformed under the bars (on both sides and center) on the lid of the inner receptacle (Photo A.App1-89).
(4) No penetration holes or dents such as those left by rod bolts of the inner receptacle of Prototype No. 1 were produced on the back of the outer receptacle lid of Prototype No. 2 (Photo A.App1-89).
(5) The zone on the back of the lid of the outer receptacle, which corresponds to the corner facing downward during the drop tests to suffer the impact force first, was less deformed than estimated from outside (similarly to Prototype No. 1). No trace of collision with the inner receptacle was found (Photo A.App1-92).
(6) The corner of the body of the outer receptacle, which was made to suffer the impact force first during the drop tests, was slightly compressed (Photo A.App1-93).
(7) No deformation occurred in the protective rectangular pipe on the inner receptacle flange inside the outer receptacle (Photos A.App1-90 and A.App1-91).
(8) No deformation or other damage was found in the corner zone of the inner receptacle which was made to suffer the impact force first. No damage, bulge or other deformation was observed on the inner receptacle (Photos A.App1-94 to A.App1-96).
(9) None of the rod bolts in the inner receptacle was damaged, loosened or removed. No dent or other deformations were found on the bolt seats (Photos A.App1-94 to A.App1-96).
(10) On the plate simulating the double boronic stainless steel plate located between two pellet storage box assemblies in the center of the inner receptacle, the two fixing blocks on top were slightly deformed and one of the two flat head screws was broken. However, the double plate simulating boronic plate was not broken or cleft. Of the fixing blocks on the lower level, one flat head screw was broken, releasing the dummy boronic plate toward the pellet storage box assembly 1, but this was still within its effective zone. The effectiveness of the dummy neutron absorber was not lost because it remained in a limited space similarly to the lateral dummy II - A.App1 - 41
boronic plate (Photos A.App1-97 to A.App1-102).
(11) Regardless of the side of the package selected for first touchdown in the drop tests, the plates simulating boronic plates did not leave their effective zones since they are installed in a very limited space between the pellet storage box assemblies and the inner receptacle. Thus, even if they should be separated from their specified positions, no significant deformation or damage would occur (Photos A.App1-103 and A.App1-104).
(12) No significant deformation occurred in the pellet storage box assemblies. The partitions, the rubber blocks for positioning the boxes, the pillars and the fixing blocks for maintaining the space between partitions were not damaged or deformed (Photos A.App1-105 to A.App1-109).
(13) No significant deformation occurred in the pellet storage boxes. The contents were retained and were not scattered around in the inner receptacle.
4.3. Conclusion 4.3.1. 1.2-m drop tests The outer receptacle was not seriously deformed in any of the cases except that of the drop with the corner facing downward to suffer the impact force first. Its appearance does not show significant deformations and none of the rod bolts became loose or were significantly damaged. The inner elements of Prototype No. 1 were inspected after tests were completed in all the cases. Despite very demanding conditions, the inner receptacle was not seriously deformed, the rod bolts were not broken and the lid remained fixed in place. The pellet storage box assemblies (contents) were deformed, but maintained their shape and capabilities. No openings that might release pellets of uranium oxides were created in any of the pellet storage boxes. The stainless steel plates simulating neutron absorbers in the inner receptacle as well as the partitions in the pellet storage box assemblies were slightly deformed and did not lose their required capabilities even partially. The aluminum honeycomb elements in Prototyope No. 2 were partially and slightly deformed but the inner receptacle did not suffer conspicuous damage. No deformation was found in the pellet storage box assemblies.
Thus, radioactive materials will not leak from the packaging, and no diffusion or movement of the nuclear fuel zone that should be taken into account in a criticality evaluation will occur in the packaging. No dents that might contain a 10-cm cube will be generated.
The subsequent shielding evaluation will assume conservatively that deformations have uniformly occurred in the outer receptacle and that the inner receptacle can move in the outer receptacle in which aluminum honeycomb elements are assumed not to have been installed. In addition, to simplify the model, we will assume that only uranium oxides are distributed homogeneously in the inner receptacle.
4.3.2. Penetration tests Only shallow dents were produced on the external surfaces of the package. Such dents will not affect the integrity of the package at all.
II - A.App1 - 42
4.3.3. 9-m drop tests (1) Prototype No. 1 (a) Exterior of outer receptacle Subjected to consecutive tests in different cases, Prototype No. 1 presents deformations which can reasonably be predicted . Nevertheless, it did not suffer any cracks, fractures or penetration holes that might affect the contents. No packaging elements fell off. No opening was produced in the flange. None of the rod bolts became loose, fell off or were broken.
The lid of the outer receptacle did not leave its initial required position. The lid of the outer receptacle presents larger deformations than the body of the outer receptacle since its edges have been designed with lower mechanical strength so as to absorb accidental impact load. These deformations are larger than those observed in the body but only local. Therefore, we will assume conservatively in the criticality evaluation that the outer receptacle has been deformed uniformly on its body and lid.
During a drop with the corner facing downward which produced deformation in the flange, the specimen suffered slight cracking in its weld but lost no portions of the ceramic fiber insulator. Each entire insulator block has been cut precisely to the dimensions of the compartment in the receptacle. No portion of the insulator will be separated and lost. Both Prototype No. 1 and Prototype No. 2 have the same construction.
Thus, our thermal analysis will assume that no portion of the insulator has been lost.
(b) Inner receptacle and interior of outer receptacle The inner elements of the outer receptacle also were deformed accordingly during the tests in various cases.
The honeycomb element located just behind the impact zone of the outer receptacle presents large deformations, and some portions were separated from the structural elements of the receptacle. The lateral sides of the receptacle and protective pipes for the inner receptacle flange attached to these surfaces were deformed. Therefore, these outcomes will be taken into account in our conservative assumption for our subsequent evaluations: the space in which the inner receptacle can move increases.
No openings that might form routes for leakage of the contents were produced in the lid of the inner receptacle. The body of the inner receptacle only presents bulges on its lateral sides and no cracks or clefts, especially in the weld. Some of the rod bolts caused dents and penetration holes on the back of the lid of the outer receptacle several times during the consecutive 9-meter drop tests. Some of these rod bolts themselves were deformed but were not broken. These events will be prevented from occurring in one single case by the effective honeycomb elements designed for restraining movement of the inner receptacle in the outer receptacle.
(c) Interior of inner receptacle The stainless steel plates simulating neutron absorbers on the inner surface of the inner receptacle were not separated from their initial required locations. These plates were not deformed or damaged. The double stainless steel plate simulating neutron absorber between the two pellet storage box assemblies (contents) has lost all the fixing blocks and suffered small deformations in the portions on which these blocks should have remained. However, these deformations are not significant, and no cracks or other flaws were produced in or on the dummy neutron absorber. Thus, it remained in its effective position between the pellet storage box II - A.App1 - 43
assemblies and the inner receptacle. These fixing blocks had been attached to the dummy boronic plate with a reduced fixing force to protect the plate from damage under excessive impact loads during the tests. This measure can be seen to have made sense since the plate was not broken. The neutron absorber between the two pellet storage box assemblies is composed of two thin stainless steel plates to avoid cracking under bending stresses. Our criticality evaluation will assume that neutron absorbers will remain in their initial effective positions and zones without being damaged.
The contents of the package, pellet storage box assemblies, were deformed but maintained their initial shape and capabilities. The pillars and the fixing nuts remained intact and the spacing for the partitions as neutron absorbers was maintained. No cracks were produced in the partitions which were somewhat deformed without leaving their effective positions. The rubber blocks for positioning pellet storage boxes and the fixing screws were not broken. The pellet storage boxes were held in their initial positions. No openings that might form routes for leakage of radioactive materials were produced in the pellet storage boxes since they were firmly tightened with the partitions along the vertical line of the package. Our criticality evaluation will assume that the fuel areas remain in the initial zones of the pellet storage boxes.
The bulges on the inner receptacle and the deformations in the pellet storage box assemblies which were observed on the specimen will be ignored conservatively in the criticality evaluation because such mechanical consequences are factors which increase the spacing between fuel areas.
(2) Prototype No. 2 (a) Exterior of outer receptacle Before being subjected to thermal tests, Prototype No. 2 had to be made to drop in the same position with the same corner facing downward in the 1.2-meter drop, 9-meter drop and 1-meter drop onto penetrating bar tests to provide an effect of superposition on the flange, thus making the specimen more vulnerable during thermal tests. Prototype No. 2 presents similar deformations as those observed in Prototype No. 1 upon a 9-meter drop onto penetrating bar test: the deformation affected the flange. Nevertheless, no openings were created in the flange, and none of the rod bolts were broken or separated from their required positions, so that the lid of the outer receptacle remained in its initial required position. A portion of the insulator was exposed through a crack in the weld, but no portions of it were lost.
(b) Interiors of inner and outer receptacle The aluminum honeycomb elements were partially deformed. No dents such as those observed on Prototype No. 1 were created by rod bolts on the back of the lid of the outer receptacle. The urethane rubber guides maintained their integrity and practically retained the inner receptacle in its initial position. Deformation of the corner of the inner receptacle behind the corner of the outer receptacle was less serious than estimated from outside. The inner receptacle presents no significant deformations and the rod bolts were not released from their required positions, were not broken, and were not deformed.
The stainless steel plates simulating neutron absorbers on the inner surfaces of the inner receptacle were not separated from their initial required positions, were not deformed and were not broken. Some of the fixing blocks on the dummy boronic plate between the two pellet storage box assemblies were broken, but the II - A.App1 - 44
dummy plate did not suffer significant deformations or fracture and remained in its effective zone.
The pellet storage box assemblies were slightly deformed but maintained their initial shape and capabilities.
The pellet storage boxes and positioning rubber blocks were not deformed or damaged.
4.3.4. 1-m drop onto penetrating bar tests The 1-meter drop onto penetrating bar test with the wider lateral side of the specimen inclined but facing downward produced a dent of 55 mm (maximum depth). No cracking or penetration occurred on the external surfaces of the outer receptacle in any of the other cases of orientation. During the 1-meter drop onto penetrating bar tests, the outer receptacle suffered small local deformations but no bulges on its inner surfaces.
- 5. Conclusion Two prototype packages were subjected to a consecutive series of drop tests: 1.2-meter drop, steel rod penetration, 9-meter drop and 1-meter drop onto penetrating bars. The packagings were sufficiently rigid to demonstrate the expected capabilities. Our subsequent evaluations will take into account the data on the deformations and fractures recorded during these tests, combined with additional conservative assumptions in view of the uncertainty of reproducibility of the prototype tests.
II - A.App1 - 45
Photo A.App1-1: Photo A.App1-2:
General View of Lid of Outer Prototype Transport Receptacle Opened Packaging Photo A.App1-3: Photo A.App1-4:
General View of General View of Inner Receptacle Pellet Storage Box Assembly Photo A.App1-5: Photo A.App1-6:
Gross Weight Gross Weight Adjusting Plates (on Adjusting Plate (on top of the contained bottom of the inner receptacle) receptacle)
Photo A.App1-7: Photo A.App1-8:
Accelerometer Accelerometer Attached to Outer Attached to Inner Receptacle Receptacle Photo A.App1-9: Photo A.App1-10:
Cabling Hole for Cabling Hole for Accelerometer in Accelerometer in Prototype No. 1 Prototype No. 2 II - A.App1 - 46
Photo A.App1-11: Photo A.App1-12:
General View of Drop Test Target Drop Test Target and Backboard Photo A.App1-13: Photo A.App1-14:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for having struck the 1.2-m drop in test target during horizontal 1.2-m drop in orientation with lid horizontal facing downward orientation with lid facing downward Photo A.App1-15: Photo A.App1-16:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for having struck the 1.2-m drop in test target during horizontal 1.2-m drop in orientation with horizontal narrower lateral side orientation with facing downward narrower lateral side facing downward Photo A.App1-17: Photo A.App1-18:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for (detail) having 1.2-m drop with struck the test target corner facing during 1.2-m drop downward with corner facing downward Photo A.App1-19: Photo A.App1-20:
Specimen Specimen (Prototype No. 1) (Prototype No. 1) to (detail) tested for be tested for steel 1.2-m drop with rod penetration corner facing downward II - A.App1 - 47
Photo A.App1-21: Photo A.App1-22:
Specimen Specimen (Prototype No. 1) (Prototype No. 1) tested for steel rod tested for steel rod penetration (rod penetration (rod dropped onto bolt dropped onto fusible plug) outer receptacle)
Photo A.App1-23: Photo A.App1-24:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for 9-m having struck the drop in horizontal test target during orientation with lid 9-m in horizontal facing downward orientation with lid facing downward Photo A.App1-25: Photo A.App1-26:
Impact surface of Specimen the lid after 9-m (Prototype No. 1) drop in horizontal having struck the orientation with lid test target during facing downward 9-m drop in horizontal orientation with lid facing downward (deformed lateral side)
Photo A.App1-27: Photo A.App1-28 Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for 9-m having struck the drop in horizontal test target during orientation with 9-m drop in narrower lateral side horizontal facing downward orientation with narrower lateral side facing downward Photo A.App1-29: Photo A.App1-30:
Specimen Specimen (Prototype No. 1) (Prototype No. 1) tested for 9-m drop tested for 9-m drop in horizontal in horizontal orientation with orientation with narrower lateral side wider lateral side facing downward facing downward (picture taken after (picture taken after drop with corner drop with corner facing downward) facing downward)
II - A.App1 - 48
Photo A.App1-31: Photo A.App1-32:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for 9-m having struck the drop in inclined test target during orientation 9-m drop in inclined orientation Photo A.App1-33: Photo A.App1-34:
Detail of the lid Detail of the lid having struck the having struck the test target during test target during 9-m drop in inclined 9-m drop in inclined orientation orientation Photo A.App1-35: Photo A.App1-36:
Specimen Specimen (Prototype No. 1) to (Prototype No. 1) be released for 9-m having struck the drop with corner test target during facing downward 9-m drop with corner facing downward Photo A.App1-37: Photo A.App1-38:
Detail of the Penetrating bar deformed corner installed on the test having struck the target for drop tests test target during of Prototype No. 1 9-m drop with corner facing downward Photo A.App1-39: Photo A.App1-40:
Specimen to be Detail of the impact released for 1-m area having struck drop in horizontal the penetrating bar orientation with area during 1-m drop in near lid lifting horizontal attachment onto orientation with area penetrating bar near lid lifting attachment onto penetrating bar II - A.App1 - 49
Photo A.App1-41: Photo A.App1-42:
Specimen to be Detail of the impact released for 1-m area having struck drop in horizontal the penetrating bar orientation with area during 1-m drop in near leg onto horizontal penetrating bar orientation with area near leg onto penetrating bar Photo A.App1-43: Photo A.App1-44:
Specimen to be Detail of the impact released for 1-m area having struck drop in inclined the test target during orientation with area 1-m drop in inclined near lifting orientation with area attachment of wider near lifting lateral side onto attachment of wider penetrating bar lateral side onto penetrating bar Photo A.App1-45: Photo A.App1-46 Prototype No. 2 to Prototype No. 2 be released for (detail of the 1.2-m drop with corner) having corner facing struck the downward penetrating bar during 1.2-m drop with corner facing downward Photo A.App1-47: Photo A.App1-48:
Prototype No. 2 to Prototype No. 2 be released for 9-m having struck the drop with corner test target during facing downward 9-m drop with corner facing downward Photo A.App1-49: Photo A.App1-50:
Prototype No. 2 Prototype No. 2 to (detail of the be released for 1-m corner) having drop with corner struck the test target facing penetrating during 9-m drop bar with corner facing downward II - A.App1 - 50
Photo A.App1-51: Photo A.App1-52:
Prototype No. 2 Specimen to be (detail of the released for 1-m corner) have struck drop in inclined the penetrating bar orientation with the during 1-m drop center of wider with corner facing lateral side onto penetrating bar penetrating bar Photo A.App1-53: Photo A.App1-54:
Detail of impact Specimen to be area having struck released for 1-m the penetrating bar drop in inclined during 1-m drop in orientation with inclined orientation flange on wider with the center of lateral side onto wider lateral side penetrating bar onto penetrating bar Photo A.App1-55: Photo A.App1-56:
Detail of the flange Rod bolts broken in having struck the the outer receptacle penetrating bar and separated during 1-m drop in portions of inclined orientation honeycomb with flange on wider elements lateral side onto penetrating bar Photo A.App1-57: Photo A.App1-58:
Separation of Fragments of honeycomb honeycomb elements on the elements back of the lid Photo A.App1-59: Photo A.App1-60:
Dents of bolts on Dents of bolts on the back of the lid the back of the lid behind the corner B behind the corner A II - A.App1 - 51
Photo A.App1-61: Photo A.App1-62:
Dents of bolts on Dent of bolt the back of the lid (marked with )
behind the corner C on the back of the of Prototype No. 1 lid behind the corner D of Prototype No. 1 Photo A.App1-63: Photo A.App1-64:
Dents of bolts on Dents of bolts on the back of the lid the back of the lid of Prototype No.1 of Prototype No.1 caused during drop caused during drop with narrower lateral with narrower lateral surface facing the surface facing the ground. The dent ground marked with a small is that caused by a positioning pin.
Photo A.App1-65: Photo A.App1-66:
Bolts and Interior of the outer positioning pins of receptacle of Prototype No.1, Prototype No.1 after deformed during drop with narrower drop with narrower lateral surface facing lateral surface facing the ground the ground Photo A.App1-67: Photo A.App1-68:
Dents of inner Dent of inner receptacle flanges receptacle flange on on the inner surface the inner surface of of outer receptacle outer receptacle of of Prototype No.1 Prototype No.1 Photo A.App1-69: Photo A.App1-70:
Inner receptacle Dent of a rod on flange of Prototype the lid of inner No.1 after collision receptacle of with the inner Prototype No.1 surface of the outer receptacle, and deformed corner (marked with )
II - A.App1 - 52
Photo A.App1-71: Photo A.App1-72:
Deformed rods on Deformed rod bolt the lid of inner seat on the inner receptacle of receptacle of Prototype No.1 Prototype No.1 Photo A.App1-73: Photo A.App1-74:
Bulge on a lateral Dummy neutron surface of the inner absorbers on the receptacle of inner lateral surfaces Prototype No.1 of the inner receptacle, and weight adjusting lead plates on the bottoms of Prototype No.1 Photo A.App1-75: Photo A.App1-76:
Displacement of the Broken fixing blocks dummy neutron on top of the absorber (B-SUS) in central partition of the center of the the inner receptacle inner receptacle of of Prototype No.1.
Prototype No.1 No significant deformation in the neutron absorbers (B-SUS)
Photo A.App1-77: Photo A.App1-78:
Broken fixing block Pellet storage box on the foot of the assembly 1 of inner receptacle Prototype No.1 central partition of Prototype No.1. No significant deformation in the neutron absorbers (B-SUS)
Photo A.App1-79: Photo A.App1-80:
Pellet storage box B-SUS partition of assembly 2 of Prototype No.1 Prototype No.1 II - A.App1 - 53
Photo A.App1-81: Photo A.App1-82:
Pellet storage box of Pellet storage box Prototype No.1 Photo A.App1-83: Photo A.App1-84 Pellet storage box Interior of pellet storage box Photo A.App1-85: Photo A.App1-86 Interior of pellet Interior of pellet storage box storage box Photo A.App1-87: Photo A.App1-88:
Interior of pellet Separated storage box honeycomb elements on the back of the lid of Prototype No.2 and dispersed fragments of adhesive Photo A.App1-89: Photo A.App1-90:
Deformed Deformed honeycomb element honeycomb element on the back of the behind the corner lid of Prototype of Prototype No.2 No.2 which was made to strike the test target first II - A.App1 - 54
Photo A.App1-91: Photo A.App1-92:
Deformed Back of the lid of honeycomb element Prototype No. 2 on a narrower lateral behind the corner side of Prototype which was made to No. 2 strike the test stand first Photo A.App1-93: Photo A.App1-94:
Portion of the body Portion of the inner of receptacle of receptacle of Prototype No. 2, Prototype No. 2, located closest to located closest to the corner which the corner which was made to strike was made to strike the test stand first the test stand first Photo A.App1-95: Photo A.App1-96:
Narrower side of Narrower side of the inner receptacle the inner receptacle of Prototype No. 2 of Prototype No. 2 Portion closest to the corner of outer receptacle which was made to hit the test stand first Photo A.App1-97: Photo A.App1-98:
Fixing point of the Fixing point of the dummy B-SUS dummy B-SUS neutron absorber in neutron absorber in the center of the the center of the inner receptacle of inner receptacle of Prototype No. 2 Prototype No. 2 Photo A.App1-99: Photo A.App1-100:
Dummy B-SUS Dummy B-SUS neutron absorber in neutron absorber in the center of the the center of the inner receptacle of inner receptacle of Prototype No. 2 Prototype No. 2 II - A.App1 - 55
Photo A.App1-101: Photo A.App1-102:
Lower fixing point Lower fixing point of the dummy of the dummy B-SUS neutron B-SUS neutron absorber in the absorber in the center of the inner center of the inner receptacle of receptacle of Prototype No. 2 Prototype No. 2 Photo A.App1-103: Photo A.App1-104:
Displacement of the Locations of the dummy B-SUS dummy B-SUS neutron absorbers neutron absorbers on the inner on the inner receptacle of receptacle of Prototype No. 2 Prototype No. 2 Photo A.App1-105: Photo A.App1-106:
Cover for pellet Cover for pellet storage box storage box assembly assembly of of Prototype No. 2 Prototype No. 2 Photo A.App1-107: Photo A.App1-108:
Pellet storage box Pellet storage box assembly of assembly of Prototype No. 2 Prototype No. 2 Photo A.App1-109:
Pellet storage box assembly of Prototype No. 2 II - A.App1 - 56
Appendix 2 to Chapter II-A Low-temperature Characteristics of Major Materials II - A.App2 - 1
- 1. Introduction Austenitic stainless steel (equivalent to SUS 304), chromium-molybdenum steel (equivalent to SCM 435) and aluminum alloy are used as metallic materials of the type GP-01 packaging which Nuclear Fuel Industries has designed for transporting pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium enriched to five weight percent or less. This document will describe how these metallic materials keep their original capabilities in low-temperature environments of -40°C.
- 2. Low-temperature characteristics of austenitic stainless steel (equivalent to SUS 304)
It is known that some types of austenitic stainless steel (SUS 304 and SUS 316) have distinguished low-temperature strength and toughness. Thus, these types of stainless steel used for the type GP-01 packaging keep their tensile and impact characteristics at low temperatures to some extent and do not fail to exert their capabilities in the range of temperatures considered (Figs. II-A.App2-1 and II-A.App2-2).
Fig. II-A.App2-1: Tensile Characteristics at Low Temperatures of Austenitic Stainless Steel Fig. II-A.App2-2: Impact Characteristics of Austenitic Stainless Steels at Low Temperatures Source: Stainless Steel Data Book compiled by Japan Stainless Steel Association II - A.App2 - 2
- 3. Low-temperature characteristics of chromium-molybdenum steel (equivalent to SCM 435)
Chromium-molybdenum steel is a type of low-alloy steel composed of a mixture of iron, chromium and molybdenum. When treated by quenching and annealing, it obtains a high mechanical strength. Thus, the chromium-molybdenum steel (equivalent to SCM 435) used for the type GP-01 packaging keeps its tensile and impact characteristics at low temperatures to some extent and does not fail to exert their capabilities in the range of temperatures considered (Figs. II-A.App2-3 and II-A.App2-4).
Proof Stress/Tesile Strength (N/mm2) 1500 10 8
Elongation (%)
1000 6
Red: T Strength 4 500 Bl: 0.2% Pr Str 2
0 0
-60 -40 -20 0 20 40 -60 -40 -20 0 20 40 Temperature (°C) Temperature (°C)
Fig. II-A.App2-3: Tensile Characteristics at Low Temperatures of Chromium-molybdenum Steel 200 150 Absorbed Energy (J))
100 50 0
-60 -40 -20 0 20 40 Temperature (°C)
Fig. II-A.App2-4: Impact Characteristics of Chromium-molybdenum Steel at Low Temperatures Source: Archives of Nuclear Fuel Industries, Ltd. (NFI)
II - A.App2 - 3
- 4. Low-temperature characteristics of aluminum alloy Aluminum and aluminum alloys are generally not liable to brittle fracture or deterioration of toughness at low temperatures and rather have higher strength and better elongation at low temperatures (Fig. II-A.App2-5).
Thus, the aluminum alloy used for the type GP-01 packaging does not fail to exert its capabilities in the range of temperatures considered.
Fig. II-A.App2-5: Tensile Characteristics at Low Temperatures of Aluminum Alloy Source: Manual for Aluminum Technologies, 1st edition, Light Metal Publishing Co., Ltd.
II - A.App2 - 4
- 5. Conclusion We examined the characteristics in an environment of -40°C of the metallic materials used for the type GP-01 packaging. Results of the examination revealed that all these materials are not liable to excessive deterioration of their tensile and impact characteristics in the range of low temperatures considered and maintain their required capabilities.
II - A.App2 - 5
Appendix 3 to Chapter II-A Supplementary Explanatory Material for Derivation of Natural Frequency
- 1. Derivation of natural frequency This supplementary describes the calculation code used to derive natural frequencies (FAP-3) and the analytical model used to evaluate natural frequencies.
- 2. About FAP-3 The calculation code (FAP-3) used in this evaluation was developed by KOZO SYSTEM, INC. to perform elastic stress analysis and natural frequency analysis of arbitrarily shaped structures composed of strands (members) and flat plate elements. The natural frequencies and stresses generated can be derived by creating a three-dimensional frame model by entering inputs such as material, cross-sectional information, and constraint conditions.
- 3. Analysis model 3.1 Overview A schematic diagram of this analysis model is shown in Figure 3.1. In this model, the lid of the outer receptacle is modeled as one piece. It has the same shape as the actual item. The model is composed of 6 flat plate elements of the outer and inner walls of the outer receptacle composed of 6 flat plate elements.
Figure 3.1 Model Schematic II-A App 3-1
3.2 Constraint conditions Constraint conditions of this analysis model are shown in Figure 3.2. The six points circled in red are constraint points.
Receptacles in transit are secured to each other and on four sides by means of strapping equipment, containers, etc., but modeling is done in such a way that the only constraint point on the model is the leg on the lower surface. Thus, the natural frequency of this model is smaller than actual. All constraint points are only translation constraints, and no rotation constraints are applied.
Figure 3.2 Modeling Elements of Interior of Receptacle II-A App 3-2
- 4. Analysis results The natural frequency of the analytical model described in section 3 was determined to be 29.8 Hz. This natural frequency is larger than that of trucks in transit (less than 20 Hz),
confirming that there is no risk of resonance.
II-A App 3-3
II-B. Thermal Analysis B.1. General (1) Thermal Designing The transport packaging, type GP-01, consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without dismantling. All the structural elements of the packaging are made of stainless steel. These structural elements do not include materials of different coefficients of thermal expansion. Thus, the model of packaging will not be deformed when the ambient temperature changes.
The outer receptacle has a multi-caisson-shaped double structure composed of frames, inner plates, and outer plates welded. The voids between the inner plates and the outer plates are filled with a heat insulating material (synthetic mineral fiber/ceramic fiber) to retard heat conduction to the inner receptacle which embraces the material for which the packaging GP-01 has been designed. This insulating material is made of an alumina-silica based synthetic mineral fiber which has a maximum service temperature of at least 1000°C. This material has several advantages. It is manufactured as a blanket-shaped lightweight material and can easily be formed into desired shapes. Even when deformed under compressive load, its insulating capability is not affected. A fusible plug is installed at an appropriate location on each of the outer faces of the outer receptacle. If exposed to a high-temperature environment, the solder will melt to offset the pressure difference between the inner and outer plates.
Fire-resisting rubber pieces are applied to the back of the lid of the outer receptacle. These rubber pieces will start to expand at approximately 200°C in accidental fire conditions to block up the gaps between the top of the body of the outer receptacle and the lid to prevent flames from entering.
Neither a specific cooling device nor an expansion tank is installed in the packaging.
(2) Thermal analysis The package (packaging and contents) to be transported will be subjected to a thermal analysis to prove that it meets the technical requirements for Type A fissile package defined in the Regulations and in the Public Notice.
(a) Normal conditions of transport The package considered is a Type A fissile package and therefore need not be subjected to the thermal tests under normal conditions of transport which Type B packages must be subjected to: it shall be exposed to a solar radiation environment of 38°C for twelve hours a day for one week (seven cycles of 12-hour solar radiation and 12-hour no solar radiation). In fact, the Regulations require Type A packages to be exposed to a solar radiation environment of 38°C for twelve hours a day for one week (seven cycles of 12-hour solar radiation and 12-hour no solar radiation) until it presents a constant surface temperature change pattern, before being evaluated in the thermal tests under accident conditions of transport which fissile packages must be subjected to. Considering the category of the package (fissile package), our analysis will be carried out for Normal Conditions of Transport using a no-damage model (Chapter II-B, section B.4. Normal Conditions of Transport).
II - B - 1
(b) Accident conditions of transport Yi. The specimen is exposed to a solar radiation environment of 38°C for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> a day for one week (seven cycles of 12-hour solar radiation and 12-hour no solar radiation) until it presents a constant surface temperature change pattern, and is then exposed to a heat radiation environment (ambient emittance: 0.9) of 800°C for 30 minutes. During the last period of 30 minutes, the package remains exposed to heat of solar radiation. The maximum design exothermic reaction is taken into account.
Ro. Following this exposure to heat radiation, the specimen is exposed to additional cycles of 12-hour solar radiation and 12-hour no solar radiation in an atmosphere of 38°C. The maximum design exothermic reaction is taken into account. During this period, no active cooling is performed.
The Regulations require that Drop I and Drop II tests should be carried out in such ways that the specimen suffers maximum damage during thermal tests. A thermally demanding condition for the specimen will be prepared when its corner strikes the test target during drop tests. The packaging flange (joint of lid and body of the inner/outer receptacles) is regarded most vulnerable to entry of heat. In fact, the specimen was dropped in the same orientation which would cause maximum damage and have en effect of superposition in Drop I and Drop II tests as part of the prototype tests: orientation with the corner facing downward so that it strikes the test target first. To enhance the conservatism, these Drop I and Drop II tests were preceded by free drops in this package orientation under normal conditions of transport. The specimen which was thus subjected to drop tests repeatedly in the same orientation before the thermal test. Our thermal analysis adopted a model which conservatively took into account the data on the deformations in the prototype packaging and the measured temperatures to evaluate the package. Appendix 1 to Chapter II-B shows results of the thermal tests of the prototype packaging.
An unsteady heat transfer analysis was carried out. More precisely, non-linear analysis methods which handle non-linear material constants and heat radiation were applied. The analytical code, Ansys version 11, was used for analytical calculations. This is a universal finite element analysis code. A preliminary analysis was carried out to check the definitive analytical model is justifiable in relation to the results of the thermal tests before proceeding to carry out the main part of the heat transfer analysis. Appendix 2 to Chapter II-B shows results of the preliminary check.
(3) Maximum quantity of decay heat The quantity of decay heat of uranium oxides, the material to be contained in the package is very small and is neglected in the thermal analysis.
II - B - 2
B.2. Thermophysical Properties of Contents Tables II-B-1 to II-B-4 show the thermophysical properties of the materials to be contained in the package (inner receptacle) which were used for the thermal analysis of the package.
Table II-B-1: Thermophysical Properties of Contents Heat Heat Temperat Specific Temperat Specific Density conductiv Density conductiv ure heat ure heat (g/cm3) ity (g/cm3) ity (K) (J/kgK) (K) (J/kgK)
(W/mK) (W/mK) 293 3.646 462 4.83 693 3.598 535 5.28 313 3.644 466 4.82 713 3.595 539 5.33 333 3.643 470 4.82 733 3.592 542 5.38 353 3.641 473 4.81 753 3.589 546 5.43 373 3.638 477 4.81 773 3.586 549 5.49 393 3.636 480 4.82 793 3.583 552 5.55 413 3.634 484 4.83 813 3.581 555 5.61 433 3.631 487 4.84 833 3.578 557 5.67 453 3.629 491 4.86 853 3.575 560 5.73 473 3.626 494 4.88 873 3.572 562 5.80 493 3.624 498 4.90 893 3.569 564 5.87 513 3.621 502 4.93 913 3.566 566 5.94 533 3.619 505 4.96 933 3.563 567 6.01 553 3.616 509 4.99 953 3.560 568 6.08 573 3.614 513 5.02 973 3.556 569 6.15 593 3.611 517 5.06 993 3.553 569 6.23 613 3.608 521 5.10 1013 3.550 570 6.31 633 3.606 524 5.14 1033 3.547 569 6.39 653 3.603 528 5.18 1053 3.544 569 6.47 673 3.600 532 5.23 1073 3.541 567 6.55 Note: The contents were homogenized with the volumetric ratios of the different materials contained in the inner receptacle: 46.2 % for air, 16.6 % for uranium oxides, 21.8 % for stainless steel, and 15.4 % for neoprene rubber. The data on uranium oxides were cited from MATPRO-Version 11 and NFIs archives. The other data were cited from Heat Transfer Engineering Data, 4th revised edition, The Japan Society of Mechanical Engineers, 1986.
Table II-B-2: Thermophysical Properties of Aluminum Honeycomb Element Specific Heat conductivity (W/mK)
Temperature Density heat X Y Z (K) (g/cm3)
(J/kgK) 300 0.0776 907 2.554 3.818 6.767 320 0.0775 921 2.552 3.814 6.759 340 0.0774 934 2.550 3.810 6.751 360 0.0772 946 2.548 3.806 6.743 380 0.0771 957 2.546 3.802 6.735 400 0.0770 966 2.543 3.798 6.727 420 0.0768 975 2.541 3.794 6.719 440 0.0767 983 2.539 3.790 6.711 460 0.0766 991 2.537 3.786 6.702 480 0.0765 998 2.534 3.782 6.694 500 0.0764 1005 2.532 3.778 6.686 550 0.0760 1022 2.526 3.768 6.665 600 0.0757 1040 2.520 3.758 6.645 650 0.0754 1060 2.491 3.712 6.562 700 0.0750 1083 2.462 3.667 6.480 800 0.0743 1140 2.404 3.577 6.315 900 0.0734 1213 2.345 3.487 6.150 1000 0.0725 1300 2.286 3.395 5.984 1100 0.0715 1391 2.226 3.304 5.817 Note: The thermophysical properties of the aluminum honeycomb element have been calculated. Refer to Appendix 2 to Chapter II-B.
II - B - 3
Table II-B-3: Thermophysical Properties of Insulating Material Heat Temperature Density Specific heat conductivity (K) (g/cm3) (J/kgK) (W/mK) 291 0.16 1050 0.031 373 0.16 1050 0.036 473 0.16 1050 0.044 573 0.16 1050 0.053 673 0.16 1050 0.064 773 0.16 1050 0.081 873 0.16 1050 0.098 973 0.16 1050 0.120 1073 0.16 1050 0.145 1173 0.16 1050 0.173 Note: These data are cited from the technical data published by the manufacturer with some modifications.
Refer to Appendix 2 to Chapter II-B.
Table II-B-4: Thermophysical Properties of Materials Adopted for Thermal Analysis Temperatu Specific Heat Density Component Material re heat conductivity (g/cm3) (W/mK)
(K) (J/kgK) 300 7.92 449 16.0 400 7.89 511 16.5 Inner/Outer Stainless steel (1) 600 7.81 556 19.0 Receptacle 800 7.73 620 22.5 1000 7.64 644 25.7 Fire-resistant rubber (1)(2) 300 0.86 2200 0.36 Silicone rubber (1) 293 0.97 1600 0.20 Rubbers 400 0.97 1500 0.19 Neoprene rubber (1) 293 1.23 2200 0.25 400 1.23 2200 0.23 Notes: (1) Heat Transfer Engineering Data, 4th revised edition, JSME, 1986 (2) The properties of ethylene propylene rubber (main component) are substituted.
B.3. Characteristics of Packaging Components The contents of the package consist of assemblies of storage boxes containing solid pellets of uranium oxides.
The assemblies and the pellet storage boxes are made of stainless steel. There is no emission of gases from the pellets which are stable solids within the range of temperatures conceivable in safety analysis. Therefore, no valves such as safety valves are provided in the packaging. Since it is needless to increase or decrease the pressure in the packaging for storing the pellets, the applicable requirements for maximum service pressure are not relevant for this package.
The O-ring installed on the flange of the inner receptacle has been designed with the following specifications:
- Material: Silicone rubber
- Service temperature range: -50 to +180°C
- Thermal aging performance: No serious deterioration at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
- Tensile strength: 3.4 MPa
- Hardness: 48 to 60 (measured with a Type A durometer)
- Elongation: 200 %
- Wire diameter: 10 mm.
II - B - 4
B.4. Normal Conditions of Transport The package is a Type A fissile package and is therefore not subjected to the thermal tests under normal conditions of transport which Type B packages must subjected to. In fact, the Regulations require Type A packages to be exposed to a solar radiation environment of 38°C until it presents a constant surface temperature change pattern, before being evaluated in the thermal tests under accident conditions of transport to which fissile packages must be subjected. Our analysis was based on this prerequisite. The package was exposed to a solar radiation environment of 38°C for one week.
B.4.1. Analytical Thermal Model B.4.1.1. Analytical model (1) Geometrical model In the preceding 1.2-meter free drop test under normal conditions of transport, Prototype No. 2 was made to drop with its corner facing downward to strike the test target first (refer to Appendix 1 to Chapter II-A).
During that test, deformations occurred mainly in the zone of lifting attachment and scarcely in the main body of the package. The analytical model used in the analysis for integrating thermal test results conservatively involved a limited insulator zone and takes into account deformations under accident conditions of transport.
This analytical model includes well the deformations observed in the 1.2-meter drop test. We removed from it those deformations under accident conditions to prepare an analytical model for use in our thermal analysis (refer to Appendix 2 to Chapter II-B). Our analysis for integrating thermal test results adopted the metal lead as dummy contents to ensure coherence with the conditions for the prototype tests. Our thermal analysis took into account uranium oxides as contents to simulate more precisely the real model of packaging.
Since the package to be analyzed has a symmetric shape, our thermal analysis was based on a modeled quarter symmetric zone (hatched zone in Fig. II-B-1) of the package. Our modeling excluded small parts of the packaging because they were regarded negligible in terms of thermal consequences.
A quarter zone was modeled.
Fig. II-B-1: Modeled Zone for Analysis II - B - 5
We excluded from our analysis those portions of the lid of the outer receptacle which are located outside the frames. The model is all the more conservative because it has contiguous stacking recesses for the legs of another outer receptacle on the lid of the outer receptacle and contiguous bolt seats on the body of the outer receptacle. Moreover, to avoid reducing our conservatism, the honeycomb elements were assumed to be free from deformation and form heat conduction paths to the inner receptacle. Fig. II-B-2 illustrates the analytical model used for our thermal analysis.
(a) View from -Y direction (b) View from +Y direction Fig. II-B-2: General View of Analytical Model The analytical model is embraced by three elements created for analyzing heat transfer through air, heat transfer by radiation during natural cooling and heat transfer by radiation of flames, respectively. Heat transfer by radiation is taken into account for the border between the internal air and the surrounding structural components of the package.
The model has 101,917 nodes and 123,375 finite elements. Figs. II-B-3 to II-B-5 show the entire finite element model and its segments.
II - B - 6
Fig. II-B-3: Finite Element Model (entire)
Fig. II-B-4: Finite Element Model (segment for calculating surface effect)
II - B - 7
Fig. II-B-5: Finite Element Model (segment for calculating surface effect and internal radiation)
(2) Analysis conditions The conditions specified in the Regulations should be adopted for our analysis. The following paragraphs summarize the analysis conditions adopted.
(a) Heat transfer between packaging components All the components and parts of the packaging are assumed to be in tight contact with each other as long as they are in contact geometrically. No loss of heat transfer occurs in the analysis since the model was created with the nodes shared by the relevant elements.
(b) Heat transfer under Appendix 4-1 to Public Notice The set of two conditions shown below is applied for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> followed by an interval of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, this cycle being further repeated six times within one week (total: 7 cycles).
Yi: Applying a heat input with the specified heat flux and a heat release by radiation to simulate a thermal condition in the daytime
- According to the tables in Appendix 4-1 to the Public Notice, the following energies are applied:
800 W/m2 to the external horizontal and upward-facing surfaces of the packaging 200 W/m2 to the external vertical surfaces of the packaging.
These energies are directly applied with heat flux to the relevant external surfaces of the packaging.
- Applying radiation of heat from the external surfaces of the outer receptacle to the surrounding space (atmospheric temperature: 38°C). The outer receptacle is made of stainless steel. The Heat Transfer Engineering Data (4th revised edition, The Japan Society of Mechanical Engineers, 1986) includes data on the radiation II - B - 8
factor for stainless steel in Figure 1(a), page 184. It indicates a range of 0.1 to 0.2 for 0°C to 800°C. We adopted 0.1 to stay conservative. Ansys surface effect elements were used to apply the radiation.
Ro. Applying heat release by radiation to simulate a thermal condition in the nighttime
- Applying radiation of heat from the external surfaces of the outer receptacle to the surrounding space (atmospheric temperature: 38°C). A radiation factor of 0.1 was adopted as in the previous section. Ansys surface effect elements were used to apply the radiation.
(c) Heat transfer to packaging surfaces by convection of surrounding fluid If the surrounding fluid is in the state of convection at 38°C, a heat balance occurs on the external surfaces of the packaging. This heat balance was applied. The coefficient of heat transfer was regarded as function of Nusselt number. The Nusselt number was retrieved from the IAEA transport regulations TS-G1.1 728.31.
Ansys surface effect elements were used to apply the heat transfer. The coefficient of heat transfer and nucelt number Nu are expressed by the following equation.
The coefficient of heat transfer is as function of Nusselt number:
Nu l : heat conductivity, lrepresentative length (outer receptacle height exc. legs : 0.915 m The Nusselt number was calculated with the formula shown in the IAEA transport regulations TS-G1.1 728.31 Nu 0.13PrGr 1 3 where Prandtl number Pr = / (: kinetic viscosity; : coefficient of thermal diffusivity (=/c); : density; c: specific heat)
Grashof number Gr = g (Tw - T) I3/ 2 (g: gravitational acceleration; : coefficient of volumetric expansion; Tw: wall temperature; T: air temperature)
Table II-B-5 shows results of calculation for coefficients of heat transfer.
Table II-B-5: Coefficients of Heat Transfer Coefficient of Coefficient of Temperature Temperature heat transfer heat transfer (K) (K)
(W/m2K) (W/m2K) 311 0 550 7.942 320 3.858 600 7.988 340 5.460 650 7.975 360 6.250 700 7.965 380 6.742 800 7.878 400 7.082 900 7.783 420 7.326 1000 7.619 440 7.509 1100 7.448 460 7.643 1200 7.273 480 7.748 1500 6.758 500 7.826 - -
II - B - 9
(d) Heat transfer by radiation through air in the packaging A real package contains air between the external surfaces of the inner receptacle and the internal surfaces of the outer receptacle and between the internal surfaces of the inner receptacle and the external surfaces of the pellet storage box assemblies. Assuming that no convection is present in the internal air, this air was regarded as a heat transferring material (or solid for which physical properties corresponding to the air are applied) in our analysis. Heat transfer by radiation was applied to the internal surfaces of the packaging which are in contact with air. Aluminum honeycomb elements occupy most of the internal surfaces of the outer receptacle.
The Heat Transfer Engineering Data (4th revised edition, The Japan Society of Mechanical Engineers, 1986) includes data on the radiation factor for aluminum in Figure 1(a), page 184. It indicates a range of 0.01 to 0.05.
We adopted 0.1 to stay conservative. To carry out the analysis with a symmetric model, radiosity was used.
(e) Symmetry boundary condition All the symmetric surfaces were handled as heat insulating conditions. Surfaces for which no condition is specified were regarded as heat insulating conditions in the heat transfer analysis.
(f) Initial temperature condition The analysis was started with the object to be analyzed which had a uniform temperature of 38°C under normal conditions of transport.
Table II-B-6 shows the heat transfer conditions used.
Table II-B-6: Heat Transfer Conditions (normal conditions of transport)
Radiation through the air Radiation by in packaging voids Heat transfer through Radiation through (outer recept. internal flames surrounding air Inflow of solar radiation surrounding air surfaceinner recpt.
Conditions (heat transfer by external surface (heat transfer condition (heat flux applied) (heat transfer by radiation inner recept. internal applied) radiation applied) applied) surfacecontents external surface)
ON Temperature Horizontal/upward-facing rise solar ON surfaces: 800 ON radiation Surrounding air at 38°C Vertical surfaces: 200 Normal ( packaging (daytime) Temperature-dependent Horizontal/downward-facing OFF ON (=0.)
Conditions external coefficient of heat surfaces: 0 surface=0.1)
Natural transfer cooling OFF (nighttime)
II - B - 10
(3) Flow of analysis Fig. II-B-6 shows the flow of the thermal analysis.
Preparations for analysis:
Modeling Specifying material constants Specifying boundary conditions Equation solution (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />)
Temperature rise (daytime)
Modifying boundary conditions Equation solution (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />)
Temperature drop (nighttime) 7 Days Passed NO YES Treatment of results including evaluation of temperatures of the inner receptacle END Fig. II-B-6: Flow of Analysis under Normal Conditions of Transport B.4.1.2. Test model This section is not applicable since no thermal tests were carried out with a prototype packaging under normal conditions of transport.
II - B - 11
B.4.2. Highest Temperatures The analytical model of package as described in section B.4.1.1. Analytical model was analyzed with the analytical code ANSYS to evaluate temperatures of the package under normal conditions of transport. This evaluation was focused on the O-ring on the flange which was regarded as thermally most vulnerable of the components of the inner receptacle, containment boundary of the package. Fig. II-B-7 shows the time-varying temperatures. Fig. II-B-8 shows the items evaluated. The temperature raised by solar heat radiation practically attained equilibrium on the fifth day. The highest temperature of the O-ring was recorded on the seventh day:
68°C, lower than the maximum service temperature for normal service (180°C). The highest temperature (114°C) in the package was recorded in the insulator close to the outer receptacle lid center. Fig. II-B-9 and II-B-10 show the temperature distributions in the entire analytical model and in the O-ring and spacers, respectively when the highest temperature was attained. Stainless steel is the main structural element of the transport packaging. Therefore, the temperature rise generated in the analysis will not adversely affect the packaging. The highest temperature (74.5°C) in the inner receptacle was generated near the lid center. The average temperature inside inner receptacle at this time is 59°C. Fig. II-B-11 shows the temperature distribution in the inner receptacle.
80 75 O-ring on narrower surface O-ring corner O-ring on wider surface 70 65 60
°C 55 50 45 40 35 30 0 1 2 3 4 5 6 7 8 Number of Days after the Start of Analysis Fig. II-B-7: Temperatures Recorded under Normal Conditions of Transport O-ring at corner oring_corner O-ring on narrower side oring_narrow O-ring on wider side oring_wide Fig. II-B-8: Points Evaluated for Temperature II - B - 12
Fig. II-B-9: Temperature Distribution in the Entire Package at End of 7th Day (unit: K)
O-ring Fig. II-B-10: Temperature Distribution in Rubber near O-ring at End of 7th Day (unit: K)
II - B - 13
Fig. II-B-11: Temperature Distribution in Inner Receptacle in Middle of 7th Day (unit: K)
B.4.3. Lowest Temperature The lowest ambient temperature was assumed to be -40°C. The contents of the package are pellets of unirradiated uranium oxides. Therefore, we assumed that no decay heat is generated in the package. When solar radiation is neglected additionally, the lowest temperature which the package can attain was assumed to be the same as the assumed ambient temperature (-40°C).
Even if the temperature of the package is cooled down to -40°C, the materials of the packaging preserve their normal capabilities. The normal lowest service temperature for the O-ring is -50°C. Thus, no trouble will occur even at -40°C.
B.4.4. Highest Inner Pressure Results of the analysis under normal conditions of transport showed that the average temperature inside inner receptacle (59°C) was attained. The highest inner pressure was determined on the assumption that the average temperature inside inner receptacle attains 59°C.
When the initial pressure in the inner receptacle is 101 kPa (absolute) at -40°C, the inner pressure P in the inner receptacle which has attained 59°C in solar radiation heat is 273 + 59
= x 101 = 144 [kPa].
273 40 II - B - 14
Hence, a gauge pressure of 43 kPa (=144 -101 [kPa]) which corresponds to the pressure difference between the interior and the exterior of the inner receptacle acts on the internal surfaces of the inner receptacle.
B.4.5. Highest Thermal Stress A stainless steel of good heat conductivity is the main structural material of the transport packaging.
Therefore, there will no steep temperature gradient in these structural stainless steel elements under normal conditions of transport (Figs. II-B-9 and II-B-11). The inner receptacle is not fixed anywhere in the outer receptacle. Even if thermally expanded, the inner receptacle will not suffer thermal stresses resulting from restraint and will not present deformation that might cause the contents to leak from the receptacle. Since different metals are not welded with each other in the packaging, no stresses will occur due to difference of thermal expansion.
B.4.6. Summary of Results and Evaluation The highest temperatures in different parts of the package under normal conditions of transport were shown in section B.4.2 Highest Temperatures. A specific zone of the package may attain 114°C. Nevertheless, there will be no deterioration in the main structural elements made of stainless steel of the packaging. The O-ring made of silicone rubber may attain 68°C, far under the maximum service temperature.
A temperature of -40°C is taken into account as the lowest for the package. At this temperature, all the materials used for the packaging maintain their required capabilities. Temperatures foreseen will never be lower than the minimum service temperature for the O-ring.
When the average temperature inside inner receptacle reaches 59°C, an inner pressure of up to 43 kPa may act on the internal surfaces of the inner receptacle. Any stresses due to a rise of the inner pressure in the inner receptacle will not affect the capabilities of the package as have been evaluated in section A.5.1.3 Calculation of stresses.
Table II-B-7 shows summarized results of the thermal analysis and evaluations for normal conditions of transport.
Table II-B-7: Evaluations of Package under Normal Conditions of Transport Item Criterion Results Evaluation Highest temperatures:
O-ring 180 °C 68 °C Meets the requirements Entire package - 114 °C -
Inner receptacle - 75 °C -
Inside of inner receptacle - 59 °C Lowest temperature: Meets the requirements O-ring -50 °C -40 °C Highest inner pressure - 43 kPa (g) Causes no problem Highest thermal stress - -
II - B - 15
B.5. Accident Conditions of Transport For the accident conditions of transport, preliminary analyses were carried out to integrate the temperature data obtained during the preceding thermal test of a prototype packaging at 800°C for 30 minutes (refer to Appendix 2 to Chapter II-B). The analytical model for calculation was considered to be relevant for further analyses and was therefore adapted to the requirements of the real tests.
Analytical calculations were carried out consecutively for the three conditions to evaluate the temperature changes in the package:
(1) Initial conditions of thermal test The specimen package is exposed to a solar radiation environment of 38°C for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> a day (cycles of 12-hour solar radiation and 12-hour no solar radiation) until it presents a constant surface temperature change pattern.
(2) Conditions of thermal test The specimen package is then exposed to a heat radiation environment of 800°C for 30 minutes. During this period, the specimen remains exposed to heat of solar radiation (the same radiation as that applied in the initial exposure).
(3) Conditions after thermal test The specimen package is exposed to additional cycles of 12-hour solar radiation and 12-hour no solar radiation in an environment of 38°C for a period long enough to verify that the zone considered for evaluation has reached its highest temperature.
B.5.1. Analytical Thermal Model B.5.1.1. Analytical model (1) Geometrical model The analytical model which had been used for tests under normal conditions of transport was used for thermal test with some modifications related to the deformations produced during. the preceding drop tests.
The model has the same geometry as that used for the analyses for integrating the results of the preceding test.
Uranium was considered instead of lead, the material which had been considered in the analyses for integrating the results of the preceding test.
To be conservative, the geometrical model has a simplified zone which corresponds to the insulator in the outer receptacle lid and includes most of the deformations produced during the drop tests in that simplified zone. A compressed insulator would increase the volumetric insulating capability of the insulator. To remain conservative in this respect, the geometrical model was based on the assumption that the portions of insulator that were deformed during the actual tests should not change their thermal properties throughout the analysis.
Accordingly, these portions were simply omitted.
In addition, we assumed that the aluminum honeycomb elements do not change their shape, and that in this way the paths for heat transmission are maintained.
II - B - 16
Fig. II-B-12 shows the analytical model used. Figs. II-B-13 to II-B-16 show cutaway views of the damage model from different angles.
The model includes 102,279 nodes and 125,973 finite elements. Figs. II-B-17 to II-B-19 show the finite element models used.
(a) View from -Y direction (b) View from +Y direction Fig. II-B-12: Analytical Model (Damage Model) (entire)
II - B - 17
Fig. II-B-13: Cutaway View of Damage Model (1/4)
Fig. II-B-14: Cutaway View of Damage Model (2/4) (from direction)
II - B - 18
Fig. II-B-15: Cutaway View of Damage Model (3/4) (from direction)
Fig. II-B-16: Cutaway View of Damage Model (4/4) (from direction)
II - B - 19
Fig. II-B-17: Finite Element Model (entire)
Fig. II-B-18: Finite Element Model (surface effect elements)
II - B - 20
Fig. II-B-19: Finite Element Model (for calculation of surface effect and internal radiation)
(2) Analysis conditions Essentially, the analysis conditions adopted were the same as those used for tests under normal conditions of transport, except for the following particulars:
(a) Heat transfer according to Appendix 5-2 to Public Notice The set of the three conditions shown below is made to occur consecutively:
Yi. Exposing the package to an environment of 38°C until it presents a constant surface temperature change pattern
- Performing the operation shown below in (b) Heat transfer according to Appendix 4-1 to Public Notice for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> followed by an interval of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of no active heat transfer, and repeating this cycle until stable equilibrium is attained. These cycles of heat transfer should occur for a total period of 10.5 days.
Ro. Exposing the package to a thermal test environment of 800°C for 30 minutes
- Applying the heat transfer by convection of the surrounding fluid of 800°C. The coefficient of heat transfer used for the analysis was 10W/(m2°C), a value retrieved from the IAEA transport regulations TS-G1.1 728.30. Ansys surface effect elements were used to apply the heat transfer.
- Applying the radiation of heat from the external surfaces of the outer receptacle to the surrounding space at an atmospheric temperature of 800°C. A radiation factor of 0.9 for the flame surface and of 0.8 for the external surface of the outer receptacle in accordance with the IAEA transport regulations TS-G1.1 728.28 II - B - 21
and 728.29. As Ansys provides for only one value for the radiation factor to be applied, the following equation was adopted:
1 2 Radiation factor F 11 1 1 2 Ansys surface effect elements were used to apply the radiation.
Ha. Applying natural cooling after fire
- Applying the heat transfer by convection of the surrounding fluid at 38°C. The coefficient of heat transfer was regarded as a function of the Nusselt number. The Nusselt number was retrieved from the IAEA transport regulations TS-G1.1 728.31 (for details of the calculation of , refer to section B.2. Thermal Properties of Contents). Ansys surface effect elements were used to apply the heat transfer.
(b) Heat transfer according to Appendix 4-1 to Public Notice The following set of two conditions was used as conditions for item Yi (see above). Only the condition for the daytime is integrated into the preceding conditions Ro and Ha.
Yi: Applying a heat input with the specified heat flux and a heat release by radiation to simulate a thermal condition in the daytime as follows:
- According to the tables in Appendix 4-1 to the Public Notice, the following energies are applied:
800 W/m2 to the external horizontal and upward-facing surfaces of the packaging 200 W/m2 to the external vertical surfaces of the packaging 400 W/m2 to the other surfaces.
These energies should be directly applied with heat flux to the relevant external surfaces of the packaging. The energy condition for the other surfaces is applied to the inclined surfaces of the damaged portions.
- Applying radiation of heat from the external surfaces of the outer receptacle to the surrounding space (atmospheric temperature: 38°C). The outer receptacle is made of stainless steel. The Heat Transfer Engineering Data (4th revised edition, The Japan Society of Mechanical Engineers, 1986) includes data on the radiation factor for stainless steel in Figure 1(a), page 184. It indicates a range of 0.1 to 0.2 for 0°C to 800°C. We adopted 0.1 to stay conservative. Ansys surface effect elements were used to apply the radiation.
Ro. Applying heat release by radiation to simulate a thermal condition in the nighttime
- Applying radiation of heat from the external surfaces of the outer receptacle to the surrounding space (atmospheric temperature: 38°C), similarly to the item Yi. A radiation factor of 0.1 was adopted, similarly to the item Yi. Ansys surface effect elements were used to apply the radiation.
(c) Coefficient of heat transfer The coefficient of heat transfer for the interface between the external surfaces of the outer receptacle and the surrounding fluid during fire, 10W/(m2°C), was retrieved from the IAEA transport regulations TS-G1.1 728.30. The -values adopted for other states are those shown in section B.4.1.1. Analytical model, (2)
Analysis conditions, (c) Heat transfer to packaging surfaces by convection of surrounding fluid on the assumption that thermal balance occurs on the external surfaces of the outer receptacle by convection of the surrounding fluid, which is kept at 38°C.
II - B - 22
Table II-B-8 shows the heat transfer conditions.
Table II-B-8: Heat Transfer Conditions (Accident Conditions of Transport)
Radiation through the air in packaging voids (outer recept. internal Heat transfer through Radiation by Radiation through surfaceinner surrounding air Inflow of solar radiation flames surrounding air Conditions recept. external (heat transfer condition (heat flux applied) (heat transfer by (heat transfer by surface applied) radiation applied) radiation applied) inner recept. internal surface contents external surface)
Before Temperature ON ON OFF ON ON (=0.)
Fire rise by solar Surrounding air at 38°C Horizontal/upward-facing ( of packaging radiation Temperature-dependent surfaces: 800 external surface=0.1)
(daytime) coefficient of heat Vertical surfaces: 200 transfer Horizontal/downward-facing surfaces: 0 Natural OFF cooling (nighttime)
Fire Ongoing fire ON ON ON OFF (coefficient of heat Horizontal/upward-facing ( of flame=0.9 transfer =10 surfaces: 800 of packaging surrounding air at Vertical surfaces: 200 external 800°C) Horizontal/downward-facing surface=0.8)
After Natural ON surfaces: 0 OFF ON Fire cooling after Surrounding air at 38°C ( of packaging fire Temperature-dependent external surface coefficient of heat =0.1) transfer II - B - 23
(3) Flow of analysis Fig. II-B-20 shows the flow of the thermal analysis.
Preparations for analyses:
Modeling Specifying material constants Specifying boundary conditions Equation solution (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />)
Temperature rise (daytime)
Modifying boundary conditions Equation solution (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />)
Temperature drop (nighttime) 10.5 Days Passed NO YES Modifying boundary conditions Equation solution (fire)
Modifying boundary conditions Equation solution (natural cooling)
Treatment of Results including O-ring positions and temperature records END Fig. II-B-20: Flow of Analysis of Package under Accident Conditions of Transport II - B - 24
B.5.1.2. Test model The analytical model described above was used to carry out thermal evaluations. Some data which we are unable to obtain with the analytical model should be collected in other ways. Thus, in parallel, a thermal test was carried out on Prototype No. 2 to acquire a temperature history for checking the relevance of the analytical model and to ascertain the behavior of the real packaging in fire test conditions. Appendix 1 to Chapter II-B shows details of the results of the thermal test of the prototype.
(1) Prototype The prototype packaging used for the thermal test was the one which had already been subjected to various drop tests. Two prototype packagings were used during the drop tests: one (Prototype No. 1) was mainly to examine the orientation(s) of the specimen during the main part of the drop tests that would cause maximum damage, and the other (Prototype No. 2) was for the main part of the drop tests. The latter was tested in the orientation which would produce maximum damage: with one of its upper corners facing downward to strike the test target first. This upper corner was finally chosen for maximum damage because such orientations would allow the drop energy to be concentrated on it and produce significant deformation, and because this portion of the package was located close to the flange which was regarded as most vulnerable to thermal stresses during the thermal test and likely to suffer damage (cracking or cleaving) under drop energy to form a path for heat during the thermal test.
During the drop tests, deformations occurred in the package up to the flange. No openings were produced in the flange. None of the rod bolts for tightening the lid on the body of the outer receptacle were pulled out or fractured. The lid of the outer receptacle stayed in its required position. Cracks were produced in the welds of the lifting attachment, resulting in partial exposure of the insulator. Nevertheless, no portions of the insulator were lost . In the interior of the outer receptacle, the aluminum honeycomb elements were partially deformed.
The inner receptacle and the pellet storage box assemblies suffered no significant deformation. Appendix 1 to Chapter II-A shows details of the results of the prototype drop tests.
The prototype packaging (No. 2) was subjected consecutively to the drop tests and the thermal test. Essentially, this prototype packaging has characteristics and constructions identical to those of a production model except for some small differences. The only differences from a production model will be described in the following paragraphs. Two pellet storage box assemblies A were used as the contents of the package during the drop tests to increase the overall weight of the package. The same dummy contents were used in the thermal test without modification.
Differences of Prototype from a production model:
- Dummy pellets (lead rods) used as substitute for the real contents. Differences in thermal characteristics between uranium and lead were taken into account in the analytical calculations;
- Thermocouples were installed on the packaging, and thermo-labels and thermo-paint were applied to the packaging for temperature measurements. Fig. II-B-21 shows the locations at which the thermocouples were installed;
- Small portions of the honeycomb elements in the outer receptacle were cut and removed to allow installation II - B - 25
of thermocouples in those voids, and holes corresponding to these thermocouples were created;
- A normal stainless steel was used instead of the boronic stainless steel used for real neutron absorbers.
Zone which was made to strike the test target/penetrating bar first in the preceding drop tests a
d e c b
e d
b Thermocouples installed:
a c - In the atmosphere of the furnace: a
- On the external surface of the outer receptacle: b gh f - On the inner side of the flange g h of the outer receptacle: c, d, and e
f - On the flange of the inner receptacle: f, g, and h.
Fig. II-B-21: Locations of Thermocouples (2) Method used for thermal test As part of the thermal test under accident conditions of transport, a specimen of fissile package should be exposed to an environment of solar heat radiation of 38°C until it presents a constant surface temperature change pattern before being subjected to the thermal test. However, it is not possible to implement all these conditions in tests using a prototype. Thus, in our thermal test, the prototype was exposed to an environment of 800°C for 30 minutes and cooled in the ambient temperature. An analytical model created on the basis of collected data was subjected to analyses to integrate the results of the preceding tests. The required conditions were reproduced through analytical calculations to determine temperatures in the package.
The analyses for integrating the results of the preceding tests were preceded by a preliminary temperature rise test and a delivery procedure verification rehearsal. A method was then defined for the thermal test and the following procedure was applied:
Raise the temperature in the furnace to 1000°C and maintain this temperature for at least 60 minutes.
Have a forklift truck lifting the prototype (specimen) ready for delivery of the prototype in front of the furnace; open the port of the furnace and pull out the carriage.
Place the prototype in the predetermined location on the carriage and immediately place the prototype on the carriage into the furnace. Close the port of the furnace.
Set the temperature to 820°C+/-20. When a temperature of at least 800°C has been reached in the furnace and on the thermocouples installed for measuring in-furnace temperatures, wait 30 minutes while maintaining the current equipment status.
II - B - 26
Recover the prototype in a sequence opposite to the procedure for introducing it, and leave it indoors to undergo natural cooling at room temperature until the next day.
(3) Test results The rubber materials were burnt and lost, and the external surfaces of the prototype changed their colors. The prototype kept its geometrical shape of package and presented no significant deformation. The interior of the outer receptacle and the external surfaces of the inner receptacle changed their colors but presented no deformation or any trace of ignition. The interior of the inner receptacle and the contents kept their original colors and presented no alteration throughout the thermal test. Appendix 1 to Chapter II-B shows the details of the results of the thermal test.
Temperatures of up to 144°C were recorded in the silicone rubber O-ring provided on the inner receptacle flange. This O-ring retained its original elasticity. The type of O-ring used for the prototype has a normal service temperature of up to 180°C, and is a product which had demonstrated that it does not deteriorate significantly during a heat and aging resistance test at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> specified by the JIS standard. None of the 125°C thermo-labels applied to the internal surfaces of the inner receptacle responded during the test.
This suggests that the temperature did not reach 125°C.in any part of the contents. A visual check of the interior of the inner receptacle revealed that it had not been affected by the heat during the thermal test. Table II-B-9 shows the highest temperatures in different selected zones of the package during the thermal test. Fig.
II-B-21 shows a graph representing a history of temperature changes in various components of the prototype.
Table II-B-9: Measurements of Highest Temperatures with Thermocouples Time for attaining the Highest Measured Locations Thermocouple Temperature highest temperature
(°C) (counting from end of test)
In-furnace temperature (a) 818.6 External surface of outer (b) 794.8 0:00:20 receptacle Flange on wider (e) 407.1 0:06:10 side Outer Flange corner (d) 343.8 0:08:44 receptacle Flange on narrower (c) 394.6 0:07:46 side Flange on wider (h) 127.1 1:51:54 side
-Inner Flange corner (g) 143.7 1:24:50 receptacle Flange on narrower (f) 141.9 1:48:16 side II - B - 27
Fig. II-B-21: History Of Temperature Changes in Various Components of The Prototype B.5.2. Evaluation Conditions for the Package The deformations on the package corner of the package, constituting the principal damage produced during the strength tests, were taken into account. The package is a box-shaped object (rectangular parallelepiped) and has joints of two surfaces on which drop energy is likely to be concentrated. Therefore, these joints are very liable to suffer deformation. Of these joints, eight corners or zones common to three surfaces are most vulnerable to deformation. If the specimen package is dropped in a test in such a way that one of its corner strikes the test target first, maximum deformation will occur. Furthermore, of these eight corners of either receptacle, the four upper corners are located close to the flange which is thought to be most vulnerable to heat during the thermal test. We therefore decided to adopt the package orientation with one of the four upper corners made to strike the test target first in the drop tests, supposing that the specimen would be most affected by stresses during subsequent tests including the thermal test.
In fact, during the Drop I tests using Prototypes No. 1 and No. 2, deformation reached as far as the flange (refer to Appendix 1 to Chapter II-A). During the main parts (1.2-meter free drop under normal condition, Drop I (9 meters) and Drop II (1-meter target) under Accident Conditions of Transport) of the strength tests using Prototype No. 2, the specimen was dropped in an orientation in which the same corner zone might strike the test target first. These drop tests were followed by the thermal test.
The analytical model took into account the deformations generated in Prototype No. 2 during the strength tests. Most of the portions deformed were included in the conservatively simplified zone in the lid of the outer receptacle as described in section B.5.1.1 Analytical model.
II - B - 28
B.5.3. Temperatures in Package Fig. II-B-22 shows the history of temperature changes in the package under the accident conditions of transport described in section B.5.1.1 Analytical model. Fig. II-B-23 shows the history of temperature changes in an environment of solar radiation of 38°C to which the specimen was exposed before the thermal test. Fig. II-B-24 shows the history of temperature changes during the thermal test and during the cooling period following the thermal test. Fig. II-B-25 shows the evaluation points. In the environment of solar radiation of 38°C, the top surface of the outer receptacle attained equilibrium at 129°C during the third day, and the lateral sides of the outer receptacle reached equilibrium at 62°C on the fifth day. Similarly, the O-ring on the inner receptacle reached equilibrium at 66°C on the fifth day.
The temperature of the O-ring in the inner receptacle started to rise during the thermal test and attained its highest level (170°C) approximately two hours after the start of the thermal test. . Table II-B-10 shows the highest temperatures at different locations of the package under Accident Conditions of Transport. Figs.
II-B-26 to II-B-29 show the temperature distributions in the entire analytical model and in the zones of and around the O-ring and spacer at the moment immediately after the end of the thermal test at 800°C for 30 minutes and at the moment when the highest temperature was attained in the O-ring on the inner receptacle.
Throughout the thermal test using the prototype, the dummy pellets in pellet storage box assemblies (contents of the package) and the dummy neutron absorbers presented no change in condition. The thermolabels presented no thermal reaction for 125°C and over. This suggests that the highest temperature in the contents was obviously lower than that (144°C) in the inner receptacle flange. Thus, we will conservatively assume in the subsequent analytical processes that the temperature in the inner receptacle will become identical (170°C) to that in the O-ring on the flange.
II - B - 29
Table II-B-10: Highest Temperatures in Different Locations of Package under Accident Conditions of Transport Highest Temperature (°C)
Analysis Item Before thermal After thermal test test Top of outer receptacle 129.0 798.2 Corner of outer receptacle 80.4 800.7 Wider lateral side of outer receptacle 61.8 736.1 Narrower lateral side of outer receptacle 62.2 737.4 O-ring on corner of inner receptacle 65.8 169.3 O-ring on wider lateral side of inner receptacle 66.2 155.3 O-ring on narrower lateral side of inner 66.5 169.7 receptacle Fig. II-B-22: History of Temperature Changes under Accident Conditions of Transport (entire package)
II - B - 30
Fig. II-B-23: History of Temperature Changes under Accident Conditions of Transport (before thermal test)
Fig. II-B-24: History of Temperature Changes under Accident Conditions of Transport (during/after thermal test)
II - B - 31
Top/outer receptacle outside_center O-ring/corner oring_corner Corner/
outside_
O-ring/narrower oring_narrow outer corner receptacle O-ring/wider oring_wide outside Wider/ outside_
Narrower/
outer
_wide outer narrow receptacle receptacle Fig. II-B-25: Temperature Evaluation Points Fig. II-B-26: Temperature Distribution in Package (immediately after thermal test; unit in K)
II - B - 32
O-ring Fig. II-B-27: Temperature Distribution around O-ring Rubber (immediately after thermal test; units: K)
Fig. II-B-28: Temperature Distribution in Entire Package (at the moment when the highest temperature was attained in the O-ring; units: K)
II - B - 33
O-ring Fig. II-B-29: Temperature Distribution around O-ring Rubber (at the moment when the highest temperature was attained in the O-ring; units: K)
B.5.4. Highest Inner Pressure As described in section B.5.3 Temperatures in Package, the analysis for determining the highest inner pressure in the package under Accident Conditions of Transport assumed conservatively that a temperature of 170°C has been reached in the entire inner receptacle which would maintain its original leaktightness. In such cases, the inner receptacle presents an effect of thermal expansion, with a slight increase in internal volume.
Such thermal expansion was neglected to stay conservative.
We assume here an initial inner pressure of 101 kPa (absolute) in the inner receptacle at an initial temperature of 0°C. When the temperature in the inner receptacle reaches 170°C, the inner pressure will increase as follows:
273 170 P 101 164 [kPa].
273 0 Hence, a gauge pressure of 63 kPa (=164-101 [kPa]) which corresponds to the pressure difference between the interior and the exterior of the inner receptacle acts on the internal surface of the inner receptacle.
B.5.5. Highest Thermal Stress Fig. II-B-26 shows that a large temperature difference is produced among different portions of the package immediately after the thermal test. Nevertheless, as proved in the thermal test using a prototype, no deformation or other damage will occur under thermal stresses.
II - B - 34
The inner receptacle is not fixed onto any parts of the outer receptacle. Even in thermally expanded condition, it will not suffer thermal stresses resulting from restraint. Geometrical changes due to thermal expansion will remain small in the inner receptacle. Therefore, the receptacle will not present deformation that might cause displacement or leak of the contents. Moreover, since different metals are not welded together in the packaging, no stresses will occur due to difference of thermal expansion between the package elements.
B.5.6. Summary of Results and Evaluation The highest temperatures in different parts of the package under accident conditions of transport are shown in section B.5.3 Highest Temperatures.
In such conditions of transport, the temperatures of the external surfaces of the outer receptacle can reach 700 or 800°C. Nevertheless, there will be no deterioration in the main structural elements made of stainless steel of the packaging. There will be no occurrences of dissolution (fusion point of the stainless steel: 1398°C) or inflammation, or of deformations that should be taken into account in the subsequent criticality evaluation. . There will be no displacement or leakage of the contents out of the packaging. The temperature of the O-ring may reach 170°C, which is lower than its maximum service temperature (180°C). Furthermore, it has been proved that the material (silicone rubber) of the O-ring does not significantly deteriorate in the heat and aging resistance test at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> specified by the applicable JIS standard.
Even if conservatively the temperature of the boronic stainless steel plates as neutron absorbers reaches 170°C in the inner receptacle, no deformation or deterioration that should be taken into account in the criticality evaluation will occur. Moreover, displacement or leakage of the radioactive contents out of the packaging that should be taken into account in the criticality evaluation will not occur in the pellet storage box assemblies (contents).
Assuming that the inner pressure in the inner receptacle is kept in the leaktightness of the receptacle at a temperature equal to the measured highest temperature uniformly distributed in the receptacle, an inner pressure of up to 63 kPa acts on the internal surfaces of the receptacle. Stresses resulting from a rise of the inner pressure will not affect the capability of the packaging, as has been evaluated in section A.9.2.3 Thermal test.
Table II-B-11 shows the summarized results of the thermal analyses of the package under accident conditions of transport.
II - B - 35
Table II-B-11: General Evaluation of Package under Accident Conditions of Transport Item Criterion Results Evaluation Highest temperatures:
Entire package - 801 °C No deformation O-ring
- 180 °C 170 °C Meets the requirements.
Neutron absorber - 170 °C No deterioration in performance Highest inner pressure - 63 kPa (g) -
Highest thermal stress - No deformation during No effect the thermal test of the prototype Note *: No significant deterioration occurred in the heat and aging resistance test at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> specified in the standard JIS K 6257.
References:
- IAEA Safety Standards - Regulations for the Safe Transport of Radioactive Material, 2005 Edition, Safety Requirements No. TS-R-1.
- IAEA Safety Standards Series - Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material, Safety Guide No. TS-G-1.1.
- Japan Stainless Steel Association, Manual for Stainless Steel
- The Japan Society of Mechanical Engineers, New Edition of Manual for Mechanical Engineering
- The Japan Society of Mechanical Engineers, Data for Heat Transfer Engineering, 4th revised edition
- D.L. Hargman, G.A. Reymann and R.E. Mason, MATPRO-Version 11 (revision 2) - A Handbook of Materials Properties for Use in the Analysis of Light Water Reactor Fuel Rod BehaviorNUREG/CR-0497, TREE-1280, Rev. 2 (1981).
- N. Ogasawara, M. Shiratori, Yu Qiang and T. Kurahara, Evaluation of coefficient of orthotropic heat transfer of honeycomb material, report No. 99-0011, Bulletin (Title B) of The Japan Society of Mechanical Engineers, vol. 65, issue 639, 1999-11.
II - B - 36
Appendix 1 to Chapter II-B Results of Prototype Thermal Test II - B.App1 - 1
- 1. Introduction The document describes the results of a prototype thermal test carried out on the Type GP-01 transport packaging developed by Nuclear Fuel Industries, Ltd. for containing and transporting pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium, enriched to 5 weight percent or less. The specimen used for this thermal test was the prototype packaging which had been tested for mechanical strengths (drop tests). In those drop tests, the prototype packaging was made to drop and strike the test target and the penetrating bar with one of these corners first to suffer maximum mechanical damage.
- 2. Description of Transport Packaging (1) Designation: Type GP-01 (2) Category of package: Type A fissile package (3) Maximum enrichment: 5.0 weight %
(4) Contents: Two pellet storage box assemblies of category either A or B (5) Limitations on content loading:
- When two pellet storage box assemblies A are installed: 264 kg or less of UO2
- When two pellet storage box assemblies B are installed: 200 kg or less of UO2.
(6) Dimensions:
- Width: 830 mm
- Length: 1144 mm
- Height: 1060 mm.
Note: These values of dimension take into account the legs and the portions of the lifting attachments which protrude from the flush surfaces of the packaging.
(7) Weight
- Gross weight of a packaging: 730 kg or less
- Gross weight of a package (packaging + contents): 1300 kg or less (8) Principal materials
- Structural material: Stainless steel
- Heat insulators: Ceramic fiber
- Neutron absorbers: Boronic stainless steel
- Shock absorbers (honeycomb element): Aluminum
- Rod bolts: Chrome molybdenum steel II - B.App1 - 2
- Nuts: Stainless steel
- Spacers and skids: Silicone rubber, neoprene rubber, urethane rubber.
(9) General Characteristics Fig. II-B.App1-1 shows a general view of the package. The transport packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle. The outer receptacle has a multi-caisson-shaped double structure composed of frames, inner plates, and outer plates. The voids between the inner plates and the outer plates are filled with a heat insulating material (ceramic fiber). The lid of the outer receptacle has the same structure as that of the body of the outer receptacle. The lid of the outer receptacle is firmly joined to the body of the outer receptacle by means of rod bolts. Fire-resistant rubber blocks are installed on the back of the lid of the outer receptacle. When the ambient temperature exceeds the normal level, these rubber blocks will expand to occlude voids in the outer receptacle.
The body of the inner receptacle as well as the lid of the inner receptacle has a caisson-shaped single structure composed of thick stainless steel plates. An O-ring is provided for sealing on the flange surfaces. Like the outer receptacle, the lid of the inner receptacle is joined to the body of the inner receptacle by means of rod bolts. One of the boronic stainless steel plates is installed as partition between two pellet storage box assemblies (contents).
The packaging is designed to store two assemblies of pellet storage boxes which contain pellets (minimum elements of nuclear fuel). To construct an assembly, pellet storage boxes are stacked alternately with partitions which are penetrated by six pillars. The stacks of pellet storage boxes are fixed with nuts at the threaded top of the pillars. All the partitions except for the uppermost and lowermost one are boronic stainless steel plates which serve as neutron absorbers.
Two configurations can be selectively adopted for the pellet storage box assembly depending on the type of the pellet storage box: assembly A consisting of twelve (12) pellet storage boxes which can store up to 11 kg of UO2 per box and assembly B consisting of five (5) pellet storage boxes which can store up to 20 kg of UO2 per box. An assembly A has a maximum capacity of 132 kg of UO2 and an assembly B has a maximum capacity of 100 kg of UO2.
II - B.App1 - 3
Lifting attachment Lid of Outer Receptacle Fusible plug Flange Lid of Inner Receptacle Pellet storage box assembly Outer receptacle rod bolt Body of Outer Receptacle Inner receptacle rod bolt Flange spacer Aluminum honeycomb element Body of Inner Receptacle Assembly cover Inner plate Outer plate Insulator Leg Fork guard Fig. II-B.App1-1: General View of Type GP-01 Transport Package II - B.App1 - 4
- 3. Tests 3.1. Prototype Packaging Prototypes No. 1 and No. 2 were used for the preceding drop tests. Prototype No. 1 was mainly used for examining and verifying orientations of the package to be adopted for the main part of the drop tests.
Prototype No. 2 was used for the main part of the thermal test. During the drop tests, this prototype was dropped in the orientation determined in the preliminary tests with Prototype No. 1. This orientation was supposed to cause maximum damage to the upper corner of the package. The specimen was released from a height in such an orientation that this zone might strike the test target plate or the penetrating bar first. This upper corner was chosen for maximum damage because such orientations would concentrate the drop energy on it to produce significant deformation and because this portion of the package was located close to the flange which was regarded most vulnerable to thermal stress during the thermal test and would present opening under drop energy to form a path for heat during the thermal test.
Appendix 1 to Chapter II-A shows the detail of the results of the prototype drop tests. During these tests, deformations occurred in the package up to the flange. No opening was produced in the flange and none of the rod bolts for tightening the lid on the body of receptacle were pulled out or fractured. The lid of the outer receptacle stayed in its required position. Small cracks were produced in the welds of the lifting attachment, and the insulator got partially exposed but was not lost at all (Photos B.App1-1 to B.App1-3).
In the interior of the outer receptacle, the aluminum honeycomb elements were partially deformed. The inner receptacle and the pellet storage box assemblies suffered no significant deformation (Photos B.App1-4 to B.App1-6).
The prototype packaging (No. 2) was subjected consecutively to the drop tests and the thermal test. This prototype packaging has essentially been designed with characteristics and constructions identical to those of a production model except for some small differences. The differences from a production packaging will be described in the following paragraphs. Two pellet storage box assemblies A were used as contents of the package during the drop tests because of the greater loading capacity of the type of assembly. The same dummy contents were used in the thermal test.
(1) Dummy contents The prototype to be subjected to the thermal test contains lead rods (dummy pellets) instead of real pellets of uranium oxides since a packaging containing real pellets of uranium oxides cannot be subjected to physical tests. The total weight of the dummy pellets was adjusted to become greater than the maximum possible total weight of real pellets that can be loaded in the pellet storage boxes. Lead has thermal properties which differ from those of uranium oxides. Therefore, the thermal analyses which will be carried out on the bases of results of the thermal test will use corrected data.
(2) Attaching thermocouples (Photo B.App1-7 to B.App1-14)
Upon completion of all the drop tests, Prototype No. 2 was sent to a facility of the company Sakaguchi Seisakusho. The accelerometers used for drop tests were removed. Thermocouples, thermo-labels and thermo-paint were applied instead to the package for temperature measurements. It was imperative, but not possible in the normal way, to remove the lid of the outer receptacle to attach these measuring means. A rod II - B.App1 - 5
bolt located near the deformed zone of the outer receptacle could not be removed in the normal way and had to be cut with a grinder. Opening or closing of the inner receptacle was possible only by loosening the rod bolts.
Fig. II-B.App1-2 shows the locations where thermocouples were attached. Thermo-labels were applied to the flange of the inner receptacle where lower temperatures were likely to prevail. Thermo paints were applied to the internal side of the flange of the outer receptacle where higher temperatures were likely to be produced during the thermal test.
The model of thermocouple used was suitable for measurement of temperatures during the thermal test since it is capable of measuring 1000°C and over. The large diameter of this model is suitable for avoiding short-circuiting due to the heated sheath which is exposed to flames in the furnace. The sheath was covered with a ceramic fiber heat insulator before the thermal test.
The thermo-label is capable of indicating a range of five temperature change points. Three kinds of thermo-labels which correspond to three temperature ranges were prepared. Five types of thermo-paint were prepared.
They were applied to surfaces which would be exposed to higher temperatures.
The technical data of the thermocouples, thermo-labels and thermo-paints are shown below.
Thermocouples
- Manufacturer: Sukegawa Denki Company, Ltd.
- Type/category: Type T35, category K
- Sheath dimensions: 4.8mm x 15000 mm (length)
Thermo-labels and Thermo-paints
- Manufacturer: Nichiyu Giken Kogyo Co., Ltd.
- Types of thermo-label: 5E-125 (125-160°C), 5E-170 (170-210°C),
5E-210 (210-250°C)
- Types of thermo-paint:: No. 25 (250°C), No. 31 (310°C), No. 36 (360°C), No. 41 (410°C), and No. 45 (450°C)
Zone which was made to hit the test target first in the preceding drop tests a
d e c b
Thermocouples installed:
e - In the atmosphere of the d
b furnace: a a c - On the external surface of the outer receptacle: b
- On the inner side of the flange gh f of the outer receptacle: c, d, and g h e f
- On the flange of the inner receptacle: f, g, and h.
Fig. II-B.App1-2: Locations of Thermocouples II - B.App1 - 6
(3) Additional measures for installing thermocouples The portion of honeycomb element which had been set aside for avoiding contact with the accelerometers during the drop tests was reworked: one end was cut off for providing room for installing thermocouples and was reinstalled in the void. The bracket for accelerometer which had been attached for the preceding drop tests was removed.
The hole arrangement which had been used for the cabling of the accelerometer was reused for routing the thermocouples. This routing hole is 30 mm in inner diameter. The portion of the insulator concerned had been removed and a steel pipe had been welded on the hole (Photo B.App1-15). When the installation of thermocouples was complete, the hole was plugged with fragments of ceramic fiber insulator set aside when the hole was made, to prevent flames from entering.
To fix the sheathed sections of the thermocouples, small thin stainless steel strips were spot-welded on the receptacles. For the sheathed section of the thermocouples for O-ring on the inner receptacle, small pieces of stainless steel rectangular pipe were spot-welded on the pellet storage box assemblies, and these fragments were covered with small pieces of stainless steel plate. All these fixing materials are small and can be neglected for thermal consequences.
(4) Dummy neutron absorbers Instead of real neutron absorbers made of boronic stainless steel plate for inner receptacle and pellet storage box assembly, stainless steel plates of the same dimensions were used. Use of these dummy neutron absorbers will not affect the outcome of the thermal test.
(5) Other measures taken The weight adjusting materials used for the preceding drop tests were removed when the thermocouples were installed.
(6) Differences of prototype packaging from production model of packaging The characteristics of a definitive production model of packaging will be fixed only when several improvements in features and handling procedures have been identified after completion of manufacture of these prototype packagings and all the tests described in this document have been taken into account. Table II-B.App1-1 shows the modifications in the prototype packaging which have thus been adopted. These modifications will not lead to reduction of the margin of safety for the thermal characteristics of the production model of the type GP-01 packaging.
II - B.App1 - 7
Table II-B.App1-1: Modifications of Prototype Packaging Adopted for Production Model Element Modifications Improvements Consequences of Modifications Outer receptacle flange Spacer width was reduced to allow the spacer to Adhesiveness during The function to be performed by outer spacer avoid the uneven weld surface on the flange. construction was improved. receptacle flange spacer is not affected.
The dimensions around the rod bolts were Interference was eliminated for increased. better workability.
Lifting attachment Sharp portions on the bottom end of the Operational safety was This modification does not affect the strength.
corners were chamfered additionally. improved.
Outer receptacle Additional machining for better flatness. Workability during tightening The function to be performed by outer positioning pin was improved. receptacle positioning pin is not affected.
Process of attaching Nuts were welded on the back surface of the Machinability during The function to be performed by outer outer receptacle flange: portions of the flange were threaded construction was improved. receptacle positioning pin is not affected.
positioning pin additionally.
Aluminum honeycomb Honeycomb elements were no longer fixed Maintainability was improved. The characteristics of the honeycomb element element with an adhesive, but with a dedicated cover Repairability was improved. were not modified. This modification will not and screws. affect results of drop tests.
II - B.App1 - 8 Fixing process was changed to eliminate the Possibility of entry of foreign gaps between blocks matter into the gaps was eliminated.
Fixing method for the aluminum plate cover on Maintainability was improved.
the honeycomb plates was modified to avoid Repairability was improved.
use of adhesive agent.
The width of honeycomb for the narrower Non-functioning zones were The zones concerned do not work. The lateral surface was changed. removed. modification does not affect test results.
Urethane rubber guide MC nylon was applied to the tip of the Slidability during The function to be performed by urethane urethane rubber guide. introduction/retrieval of the rubber guide is not affected.
inner receptacle was improved.
Lid of the outer Internal frame gaps were modified and Strength under severe service The strength of the outer receptacle frame is receptacle reinforcing plates were added. Spacing for conditions was enhanced. enhanced.
ventilation holes was modified.
Flange Flange clearance was reviewed. Machinability during Strength is not affected.
construction was improved.
Workability was improved.
Leg Bottom corner was chamfered. Positioning for two-stage The function to be performed by leg is not stacking was facilitated. affected.
Dimensions of skid Skid was shortened. Positioning for two-stage The function to be performed by skid is not stacking was facilitated. affected.
Process of attaching a Nut was no longer welded on the leg, but a Maintainability was improved. The function to be performed by skid is not skid threaded boss was imbedded. Repairability was improved. affected.
Edge of lid of the Additional chamfering was carried out. Workability was improved. This modification does not affect the strength.
inner receptacle and lid Operational safety was rod enhanced.
External surface of the Mirror finishing is no longer carried out. Maintainability was improved. This modification does not affect the strength.
inner receptacle Spacing between rod Modification as a result of the modification of Interference during collision is This modification does not affect the strength.
bolts for inner frame gaps of the lid of the outer receptacle prevented.
receptacle Rod bolt seat on inner Rod bolt seat was designed as a longer hole. Workability was improved. This modification does not affect the strength.
receptacle Threaded portion of Threaded portion was made longer. Dimensions after tightening This modification does not affect the strength pillar for pellet storage were optimized. of the assembly.
box assembly Process of fixing pillar Welding was replaced by a detachable structure. Maintainability was improved. This modification does not affect the strength II - B.App1 - 9 for pellet storage box Repairability was improved. of the assembly.
assembly Process of lifting pellet Insert an eye bolt into the threaded hole was Design was simplified. This modification does not affect the strength storage box assembly replaced by Attach an eye nut to the pillar. of the assembly.
Eye nut holder Eye nut holders were added on the top surface Workability was improved. This addition of elements does not affect the of the pellet storage box assembly gross weight of the package.
Rubber block for Lugs were added at both ends. Workability was improved. This modification does not affect the storage positioning pellet boxs pellet retaining capability.
storage boxes Pellet storage box The width of the handle was reduced. Workability was improved. The function to be performed by pellet storage assembly cover box assembly cover is not affected.
Note: Since each or the sum of these modifications does not affect the thermal characteristics of the package, the validity of the test results will be maintained.
3.2. Test Facility A heat treatment furnace installed at Kawanetsu Company was used as our thermal test. Kawanetsu has several heat treatment furnaces of different sizes. That we selected was the No. 3 furnace (smaller furnace) because it takes short time for return operation for overshoot and downshoot and has a sufficient capacity for storing the prototype packaging. The small furnace presents steep temperature drop while being opened after preheating process. But this characteristic is an advantage at the same time because it can be controlled easily for raising the temperature (Photo B.App1-16).
Technical Data on Test Facility: No. 3 furnace, annealing furnace with double carriage
- Internal dimensions: W 2.08 m x H 1.95 m x L 7.1 m (effective dimensions: W 2.0 m x H 1.2 m x L 6.0 m)
- Fuel: Utility gas
- Treatment temperature: Service temperatures: 625°C to 950°C; 1300°C maximum
- Temperature tolerance: +/- 10°C
- Capacity: 20 tons/charge (maximum).
3.3. Method for Thermal Test (1) Method As part of the thermal test under accident conditions of transport specified by Appendix 12 to the Public Notice, a specimen of fissile package should be exposed to:
- An environment of solar radiation kept at 38°C until it presents a constant surface temperature change
- pattern,
- An environment of 800°C for 30 minutes, and then
- An environment of solar radiation of 38°C for cooling.
It is not realistic and possible to implement the whole set of conditions in our thermal test using a prototype.
Thus, we decided to expose the specimen to an environment of 800°C for 30 minutes and then cool it in the ambient temperature. An analytical model created on the basis of collected data was subjected to analysis for integrating the results of the preceding tests. And then analytical calculations are carried out with all the three conditions to determine temperatures in the package.
The thermal test was preceded by a preliminary temperature rise test and a delivery procedure verification rehearsal. For the preliminary temperature rise test, the following procedure was applied (Photo B.App1-17):
Raise the temperature in the furnace up to 1000°C, and then keep the operating conditions of the furnace for at least 60 minutes.
Manipulate a forklift truck to lift the specimen and make it ready for delivery of the specimen in front of the furnace; open the port of the furnace and pull out the carriage.
Place the prototype at the predetermined location on the carriage and immediately introduce the prototype on the carriage into the furnace. Close the port of the furnace.
Set the temperature to 820°C+/-20. Once a temperature of at least 800°C is attained in the furnace and on the thermocouples installed for measuring in-furnace temperatures, wait 30 minutes while keeping the current operating conditions of the furnace.
II - B.App1 - 10
Retrieve the specimen in a sequence opposite to the procedure for introducing it, and subject the specimen to natural cooling at the room temperature until the next day.
(2) Collecting temperature data Temperatures in the prototype were measured with nine (9) thermocouples: eight installed on the Prototype A and one at a location outside the package in the furnace. The measurement was started shortly before the specimen was introduced into the furnace and ended in the morning of the next day. A sampling interval of two seconds was adopted for each measuring point (Photo B.App1-18).
3.4. Description and Interpretation of Thermal Test (Photos B.App1-19 to B.App1-26)
The urethane rubber on the sole of the legs started to burn intensely in flames immediately after being placed on the carriage of the furnace. The thermocouples for measuring in-furnace temperatures indicated 800°C nine minutes after the furnace port was closed, and the test facility was maintained in the current operating conditions for further 30 minutes. In view of the fact that the thermocouple for furnace control indicated an attainment of 800°C earlier than those installed on the prototype, the temperature of the entire atmosphere of the furnace must have uniformly attained 800°C.
Retrieved from the furnace, the prototype was still burning red on the carriage for a short time until it cooled down. The general surfaces of the package were oxidized in black but half covered with a white substance on its upper portion around the flange. This white substance was estimated to be ash of the burnt rubber parts.
The prototype was checked visually. No change in shape was observed in the prototype. Dissolution or deformation resulting from burning was not found in the appearance of the specimen. The molten solder in the fusible plugs showed that they had worked correctly. Small flames were seen through the thermocouple routing hole but went out soon. These flames were presumably of the tape used for filling the hole with fragments of insulator.
Table II-B.App1-2 shows the highest temperatures attained at various locations during the thermal test. Fig.
II-B.App1-3 shows the fluctuations of the recorded temperatures.
II - B.App1 - 11
Table II-B.App1-2: Highest Temperatures Recorded on Thermocouples Time for attaining the Highest Measured Locations Thermocouple Temperature highest temperature
(°C) (counting from end of test)
Interior of furnace (a) 818.6 External surface of the outer (b) 794.8 0:00:20 receptacle Flange on wider (e) 407.1 Outer receptacle side Outer Flange corner (d) 343.8 receptacle Flange on narrower (c) 394.6 side Flange on wider (h) 127.1 Inner receptacle side Inner Flange corner (g) 143.7 receptacle Flange on narrower (f) 141.9 side Zone which was made to strike the test target first in the preceding drop tests a
d e c b
e d
b a c gh f g h f
II - B.App1 - 12
900 30 min 30 In
-furnace temperature 800 External surface of the outer receptacle 700 Flange on wider side of the outer receptacle 600 Corner flange of the outer receptacle 500
°C Flange on narrower side of the outer receptacle
()
400 300 II - B.App1 - 13 Corner flange of the outer receptacle Flange on narrower side of the inner receptacle 200 Fig. II-B.App1-3: Evolutions of Temperatures (1/2)
Flange on wider side of the inner receptacle Atmosphere outside 100 0
-60 -30 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 630
()
Minutes
450 Flange on wider side of the outer receptacle Corner flange of the outer receptacle 400 Flange on narrower side of the outer receptacle 350 300 Corner flange of the inner receptacle 250
°C Flange on narrower side of the inner receptacle
()
200 Flange on wider side of the inner receptacle 150 II - B.App1 - 14 Fig. II-B.App1-3: Evolutions of Temperatures (2/2) 100 50 0
-60 -30 0 30 60 90 120 150 180 210 240 270 300 330
()
Minutes
- 4. Inspections after Thermal Test After the thermal test was complete, the specimen was opened at NFIs facility (Kumatori Works) to inspect its interior. The outer receptacle was once opened to install the thermocouples before this test. The lid was easily removed and no alteration in shape was observed in the general appearance of the package.
(1) The silicone rubber was found to have been carbonized or transformed into ash on the outer receptacle flange after burning (Photo B.App1-27).
(2) The external surfaces of the inner receptacle turned brown and the internal surface of the outer receptacle turned gray. Nevertheless, there was no sign that suggested entry of flame into the specimen (Photo B.App1-28).
(3) The 250°C to 450°C thermo-paints applied to the back of the inner receptacle turned brown. Exact description of the color changes is not possible (Photo B.App1-29).
(4) Expanded and altered fire-resistant rubber was found adhering to the top of the outer receptacle body, which suggests that the rubber material worked effectively to plug up the voids in the receptacle (Photos B.App1-30 to B.App1-34).
(5) The 250°C thermo-paints changed their color and the 310°C thermo-paints did not change their color. At several locations, some thermo-paints only changed their upper portion of their color. in different temperature zones. These partial changes of color were attributed to expanded fire-resistant rubber applied to the outer receptacle flange: it probably came over the internal surface of the outer receptacle and the thermo-paints. This fire-resistant rubber was estimated to have been excessively heated; those thermo-paints came into contact with the expanded fire-resistant rubber and changed their color; and accordingly they showed temperature indications different from those of those not affected by the expanded rubber. This explains how the thermo-couples c, d, and e showed results (343.8°C to 407.1°C) different from those indicated by these thermo-paints affected by the expanded rubber, and how the thermocouple at the receptacle corner which was not covered with fire-resistant rubber indicated values lower than those indicated by the other ones (Photo B.App1-35).
(6) Most of the thermo-labels (for 125°C to 250°C indication) applied to the rubber plate on the inner receptacle flange adhered once to the back of the inner receptacle lid and then were separated from it. These thermo-labels touched the rubber plate as well. They probably show the temperature of the inner receptacle lid. All the thermo-labels indicate that the temperature around them reached 200°C or 210°C. The thermo-labels applied to the entire zone along the inner receptacle flange indicated similar states of temperature. This suggests that the temperature distribution was uniform in the inner receptacle and was not affected by the presence of the hole for thermocouple routing (Photos B.App1-36 to B.App1-39).
(7) The spacers (silicone rubber plates) on the inner receptacle flange kept their elasticity though they turned II - B.App1 - 15
brown on their perimeter similarly to the external surfaces of the inner receptacle (Photo B.App1-40).
(8) The O-ring on the inner receptacle flange also kept it elasticity and did not alter their properties and color (Photos B.App1-41 to B.App1-44).
(9) The contents and the interior of the inner receptacle did not alter their color and there was no physical evidence proving high temperatures in the interior and contents of the inner receptacle (Photo B.App1-40).
(10) The thermo-labels applied to the dummy neutron absorbers (stainless steel plates) showed no reaction and demonstrated that the temperature of the dummy neutron absorber did not attain 125°C (Photos B.App1-45 to B.App1-48).
4.3. Summary of Test Results The thermal test caused change in color of the external surfaces of the outer receptacle. The deformations and damage which had been generated during the preceding drop tests were not aggravated during the thermal test. The thermal load of the test caused no holes in the specimen and no damage to the tightening rod bolts. The outer receptacle lid did not change its initial required position. The silicone rubber spacers on the flange were carbonized and turned into ash.
The internal surfaces of the outer receptacle and the external surfaces of the inner receptacle changed their colors but suffered no additional deformations and present no trace of ignition.
The dummy contents and interior of the inner receptacle only changed their colors but suffered no significant change or deformation during the thermal test. The highest temperature recorded of the silicone rubber O-ring on the inner receptacle flange was lower than 144°C. This O-ring kept its required elasticity. The type of O-ring adopted for this thermal test is a proven product which has a maximum service temperature of 180°C and has passed the heat and aging resistance test at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> specified by the applicable JIS standard.
The temperature of the dummy contents did not exceed 125°C, proving that it was not affected by the thermal load during the thermal test.
- 5. Conclusion The specimen (prototype packaging) which had been tested repeatedly for strength against drop impact was subjected to the 30-minute thermal test at 800°C. The thermal stresses imposed by the test caused loss by burning of the rubber material applied to the external surfaces of the package, but not significant changes in the package. These results show that the prototype packaging tested has the required heat resistance. This thermal test was carried out under conditions which partially differ from those required for ambient temperature and solar radiation heat by the Public Notice. For this reason, the values of the measured temperatures will be corrected by the subsequent thermal analysis. Results of analytical corrections will be taken into account in the definitive evaluation of the prototype.
II - B.App1 - 16
Photo B.App1-1: Photo B.App1-2:
General view of the General view of the Package which Package which underwent drop underwent drop tests tests (from another angle)
Photo B.App1-3: Photo B.App1-4:
Cleft in the weld on Interior of the outer the corner () receptacle Photo B.App1-5: Photo B.App1-6:
External view of the General view of inner receptacle pellet storage box assembly Zone behind the outer receptacle corner which was made to strike the test target or penetrating bar first in the preceding drop tests Photo B.App1-7: Photo B.App1-8:
Thermocouple Thermocouple, (external surface of thermo-label, and the outer receptacle thermo-paint and surrounding (corner of the atmosphere) inner/outer receptacle)
Photo B.App1-9: Photo B.App1-10:
Thermocouple, Thermocouple, thermo-label, and thermo-label, and thermo-paint thermo-paint (narrower-side (wider-side flange of flange of the the inner/outer inner/outer receptacle) receptacle)
II - B.App1 - 17
Photo B.App1-11: Photo B.App1-12:
Positions of Thermocouple thermocouples on routing the inner receptacle Photo B.App1-13: Photo B.App1-14:
All thermocouples All thermocouples installed on the installed inner receptacle Photo B.App1-15: Photo B.App1-16:
Thermocouple Interior of the routing hole furnace (before temperature raising)
Photo B.App1-17: Photo B.App1-18:
Test rehearsal for Measuring checking the setting instrumentation position for the specimen Photo B.App1-19: Photo B.App1-20:
Carriage retrieved Setting the specimen from the furnace in on the carriage which the required temperature has been attained II - B.App1 - 18
Photo B.App1-21: Photo B.App1-22:
Specimen which has Introducing the just been set on the specimen into the carriage furnace Photo B.App1-23: Photo B.App1-24:
Port of the furnace Specimen on the opened at the end carriage just of the thermal test retrieved from the furnace Photo B.App1-25: Photo B.App1-26:
General view of the Thermocouple and specimen shortly fusible plug on the after the test external surface of the specimen Photo B.App1-27: Photo B.App1-28:
Outer receptacle Interior of the outer flange receptacle Photo B.App1-29: Photo B.App1-30:
Thermo-paints on Fire-resistant rubber the back of the and thermo-paints inner receptacle lid on internal surface of the outer receptacle 410,360,250,310,450 II - B.App1 - 19
Photo B.App1-31: Photo B.App1-32:
Fire-resistant rubber Fire-resistant rubber on the internal on the internal surface of the outer surface of the outer receptacle receptacle (from another angle)
Photo B.App1-33: Photo B.App1-34:
Fire-resistant rubber Fire-resistant rubber and thermo-paints on the internal surface of the outer receptacle 410,360,250,310,450 Photo B.App1-35: Photo B.App1-36:
Thermo-paints on Thermo-label on the the internal surface inner receptacle of the outer flange receptacle after removal of fire-resistant rubber (same location as in Photo B.App1-33) 410,360,250,310,450 Photo B.App1-37: Photo B.App1-38:
Thermo-labels Other thermo-labels applied side-by-side on the inner on the inner receptacle flange receptacle flange (corner)
Lid Lid Photo B.App1-39: Photo B.App1-40:
Other thermo-labels Inner receptacle on the inner without the lid receptacle flange Lid II - B.App1 - 20
Photo B.App1-41: Photo B.App1-42:
O-ring on the O-ring on a wider-corner flange of the side flange of the inner receptacle inner receptacle Photo B.App1-43: Photo B.App1-44:
O-ring on a Inner receptacle narrower- side corner, O-ring flange of the inner removed receptacle Photo B.App1-45: Photo B.App1-46:
Thermo-labels on Thermo-labels on the top surface of the top surface of the content (near the the content (near the corner which was hole for made to strike the thermocouple test target or routing) penetrating bar first during the preceding drop tests)
Photo B.App1-47: Photo B.App1-48:
Thermo-labels on Thermo-labels on the dummy neutron the top surface of absorber (stainless the content (near the steel plate) hole for thermocouple routing)
II - B.App1 - 21
Appendix 2 to Chapter II-B Results of Thermal Model Analysis for Integrating Thermal Test Results II - B.App2 - 1
- 1. Introduction The Type GP-01 transport packaging developed by Nuclear Fuel Industries, Ltd. for transporting pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium, enriched to 5 weight percent or less, is classified as type A fissile transport package. Fissile packages must be subjected to the thermal test specified in Appendix 12 to the Public Notice. Accordingly, a thermal test was carried out using a prototype for this type of packaging. However, the requirements stipulated in the Public Notice include those which cannot be met in actual thermal tests, such as those for application of solar radiation. Thus, our definitive evaluation of the model of packaging will take into account results of analytical calculations. For this purpose, an analytical thermal model which conservatively includes the results of the actual thermal test should be created to carry out thermal analyses of the packaging under normal and accident conditions of transport.
Thus, the analysis for integrating thermal test results using a prototype were carried out to be able to justify the analytical model and to be able to enhance the accuracy of the thermal analysis. This document will describe the results of the analysis for integrating thermal test results.
- 2. Prototype and Results of Prototype Tests 2.1. Prototype Packaging The prototype packaging was subjected consecutively to the drop tests and the thermal test. This prototype packaging has essentially been designed with characteristics and constructions identical to those of a production model of GP-01 packaging except for small differences. The only differences from an actual packaging will be presented in the following paragraphs. Two pellet storage box assemblies A were used as the contents of the package during the drop tests because of its greater loading capacity than the assembly B. The same dummy contents were used in the thermal test.
(1) Dummy contents The prototype to be subjected to the thermal test contains lead rods (dummy pellets) which simulates the weight of real pellets of uranium oxides. Lead has its own thermal properties which differ from those of uranium oxides. The thermal analysis to be carried out subsequently correct results of the thermal test.
(2) Attaching thermocouples The accelerometers used for the drop tests were removed. Thermocouples had to be applied instead to the specimen for temperature measurements. For this purpose, it was imperative to open the outer receptacle to apply these measuring means. Several rod bolts located near the deformed zone of the outer receptacle could not be loosened for removal in the normal way and had to be cut. They were not replaced by new rod bolts or any substitute materials.
Fig. II-B.App2-1 shows the locations where thermocouples were attached. Thermo-labels and thermo-paints were applied to the flange of the inner receptacle. Thermo paints were applied to the internal sides of the outer receptacle near the inner receptacle flange.
The thermal analysis conducted after the thermal test simulated the temperatures recorded by these thermocouples.
II - B.App2 - 2
Zone which was made to strike the test target first in the preceding drop tests a d e c b
e Thermocouples installed:
d b - In the atmosphere of the a c furnace: a
- On the external surface of the outer receptacle: b gh f - On the inner side of the flange g h of the outer receptacle: c, d, and f
e
- On the flange of the inner receptacle: f, g, and h Fig. II-B.App2-1: Locations of Thermocouples Attached (3) Additional measures for installing thermocouples The hole arrangement which had been used for the cabling of the accelerometers was reused for routing the thermocouples. This routing hole is 30 mm in inner diameter. The portion of the insulator which bothered the routing was removed and a steel pipe welded on the internal surface of the hole. The hole was plugged with the remaining fragments of ceramic fiber insulator removed to prevent flames from entering, fragments produced when the hole was made.
The portions of honeycomb elements near the hole were reworked (ends cut off) for installing/routing the thermocouples.
(4) Dummy neutron absorbers For real neutron absorbers made of boronic stainless steel plate for inner receptacle and pellet storage box assembly were substituted stainless steel plates of the same dimensions. Use of these dummy neutron absorbers does not affect the thermal test.
(5) Supplementary notes The characteristics of a definitive production model of packaging will be fixed only when several improvements in features and handling procedures have been identified after completion of manufacture of these prototype packagings and all the tests described in this document have been taken into account. Table II-B.App1-1 shows the modifications in the prototype packaging which have thus been adopted. These modifications will not lead to reduction of the margin of safety for the thermal characteristics of the production model of the type GP-01 packaging.
2.2. Results of Prototype Tests (1) Drop tests Prototypes No. 1 and No. 2 were used for the preceding drop tests. Prototype No. 1 was mainly used for examining and verifying orientations of the specimen to be adopted for the main part of the drop tests.
II - B.App2 - 3
Prototype No. 2 was used for the thermal test. During the drop tests, this prototype was dropped in the orientation determined in the preliminary tests with Prototype No. 1. This orientation was supposed to cause maximum damage to the upper corner of the package. The specimen was released from a height in such an orientation that this zone might strike the test target plate or the penetrating bar first. This upper corner was chosen for maximum damage because such orientations would concentrate the drop energy on it to produce significant deformation and because this portion of the package was located close to the flange which was regarded most vulnerable to thermal stress during the thermal test and would present opening under drop energy to form a path for heat during the thermal test.
Appendix 1 to Chapter II-A shows the detail of the results of the prototype drop tests. During the drop tests, deformations occurred in the package up to the flange. No opening was produced in the flange and none of the rod bolts for tightening the lid on the body of receptacle were pulled out or fractured. The lid of the outer receptacle stayed in its required position. Small cracks were produced in the welds of the lifting attachment, and the insulator got partially exposed but was not lost at all. The cumulative deformations are modeled in Fig.
II-B.App2-2.
In the interior of the outer receptacle, the aluminum honeycomb elements were partially deformed. The inner receptacle and the pellet storage box assemblies suffered no significant deformation.
Deformation on the outer receptacle corner which was made to strike the test target first during drop tests:
R2 R1: 220 mm R2: 300 mm R3 R1 R3: 180 mm Fig. II-B.App2-2: Deformation during Drop Tests (2) Thermal test The thermocouples for measuring in-furnace temperatures indicated 800°C nine minutes after the furnace port was closed, and the test facility was maintained in the current operating conditions for further 30 minutes.
Retrieved from the furnace, the prototype was still burning red on the carriage for a short time until it cooled down. The general surfaces of the package were oxidized in black. The prototype was checked visually. No change in shape was observed in the prototype. Dissolution or deformation resulting from burning was not found in the appearance of the specimen.
The thermal test caused change in color of the external surfaces of the outer receptacle. The deformations and damage which had been generated during the preceding drop tests were not aggravated during the thermal test. The thermal load of the test caused no holes in the specimen and no damage to the tightening rod bolts. The outer receptacle lid did not leave its initial position. The silicone rubber spacers on the flange were carbonized and turned into ash.
The internal surfaces of the outer receptacle and the external surfaces of the inner receptacle changed their colors but suffered no additional deformations and present no trace of ignition.
II - B.App2 - 4
The dummy contents and interior of the inner receptacle only changed their colors but suffered no significant change or deformation during the thermal test. The highest temperature recorded of the silicone rubber O-ring on the inner receptacle flange was lower than 144°C. This O-ring kept its required elasticity. The type of O-ring adopted for this thermal test is a proven product which has a maximum service temperature of 180°C and has passed the heat and aging resistance test at 225°C for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> specified by the applicable JIS standard.
The temperature of the dummy contents did not exceed 125°C, proving that it was not affected by the thermal test.
Table II-B.App2-1 shows the highest temperatures attained at various locations during the thermal test. Fig.
II-B.App2-3 shows the fluctuations of the recorded temperatures.
Table II-B.App2-1: Highest Temperatures Recorded on Thermocouples Time for attaining the Highest Measured Locations Thermocouple Temperature highest temperature
(°C) (counting from end of test)
Interior of furnace (a) 818.6 External surface of the outer (b) 794.8 0:00:20 receptacle Flange on wider (e) 407.1 Outer receptacle side Outer Flange corner (d) 343.8 receptacle Flange on narrower (c) 394.6 side Flange on wider (h) 127.1 Inner receptacle side Inner Flange corner (g) 143.7 receptacle Flange on narrower (f) 141.9 side II - B.App2 - 5
900 3030min In-furnace temperature 800 External surface of the outer receptacle 700 Flange on wider side of the outer receptacle 600 Flange at corner of the outer receptacle 500
°C Flange on narrower side of the outer receptacle
()
400 300 Flange at corner of the inner receptacle Flange on narrower side of the inner receptacle 200 Flange on wider side of Atmosphere outside package the inner receptacle 100 0
-60 -30 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 630
()
Minutes Fig. II-B.App2-3: Evolutions of Temperatures (1/2) 450 Flange on wider side of the outer receptacle Flange at corner of the outer receptacle 400 Flange on narrower side of the outer receptacle 350 300 Flange at corner of the inner receptacle 250
°C
() Flange on narrower side of the inner receptacle 200 Flange on wider side of the inner receptacle 150 100 50 0
-60 -30 0 30 60 90 120 150 180 210 240 270 300 330
()
Minutes Fig. II-B.App2-3: Evolutions of Temperatures (2/2)
II - B.App2 - 6
- 3. Methodology for Analysis 3.1. Geometrical Modeling The type GP-01 package is a small and caisson-shaped object. Preliminary examinations led to the conclusion that assigning this package a 2-dimensional model (such as axisymmetrical model or slice model often used for thermal analysis of cylindrical objects) will greatly underestimate the heat input through the lateral surfaces of the package. Thus, a 3-dimensional model was adopted.
The prototype subjected to various drop tests including free drop, Drop I and Drop II was deformed in particular manners (refer to section 2.2. Results of Prototype Tests, (1) Drop tests). It is hardly possible to model the prototype in its real deformed shape and dimensions. Thus, we decided to cut a triangular pyramid which corresponds to the crushed portion (Fig. II-B.App2-2) from a no-damage analytical model to prepare an model to be used for our analysis. The insulator behind the cut zone should not be left exposed. Therefore, a 10-mm thick stainless steel plate is assigned to the damaged portion.
Since the prototype contains dummy pellets of uranium oxides (lead rods), the analysis for integrating thermal test results takes into account the thermal properties of lead.
3.2. Setting Analysis Conditions This section shows the thermal boundary conditions. Table II-B.App2-2 shows summarized boundary conditions.
(1) Heat transfer between package components All the components and parts of the packaging are assumed to be in tight contact with each other as long as they are in contact geometrically. The analysis assumes no loss of heat transfer because the model was created with the nodes shared by the relevant elements.
(2) Heat transfer simulating the thermal test conditions The following conditions are applied consecutively.
(a) Assuming the package to be in an isothermal state which roughly corresponds to the ambient temperature before a fire breaks out (b) Placing the package under the conditions of the thermal test The analysis adopted the in-furnace temperatures recorded in the thermal test (Fig. II-B.App2-3) to simulate the temperature of flames (or temperature of external atmosphere) during a fire. The coefficient of heat transfer used for the analysis was 10W/(m2°C), value retrieved from the IAEA transport regulations TS-G1.1 728.30. Ansys surface effect elements were used to define the heat transfer.
A radiation of heat from the external surfaces of the outer receptacle to the surrounding space is defined.
A radiation factor of 0.9 for the flame surface and that of 0.8 for the external surface of the outer receptacle in accordance with the IAEA transport regulations TS-G1.1 728.28 and 728.29. As Ansys provides for only one value of radiation factor available for the definition, the following equation was adopted:
II - B.App2 - 7
1 2 Radiation factor F 11 1 1 2 Ansys surface effect elements were used to define the radiation.
(c) Defining natural cooling after fire Heat transfer by convection of the surrounding fluid at an ambient temperature is defined. The coefficient of heat transfer was regarded as function of Nusselt number. The Nusselt number was retrieved from the IAEA transport regulations TS-G1.1 728.31 (for detail of the calculation of , refer to the section describing the properties of the materials below). Ansys surface effect elements were used to define the heat transfer.
Since the prototype packaging was cooled indoors in the thermal test, we assume in the analysis that no solar heat input will occurs.
(3) Heat transfer by radiation through air in the packaging A real package contains air between the outer surfaces of the inner receptacle and the internal surfaces of the outer receptacle and between the internal surfaces of the inner receptacle and the outer surfaces of the pellet storage box assemblies. Assuming that no convection is occurring in the internal air, this air was handled as a heat transferring material (or solid for which physical properties corresponding to the air are defined) in our analysis. For the internal surfaces of the packaging which are in contact with air, heat transfer by radiation was defined. Aluminum honeycomb elements occupy most of the internal surfaces of the outer receptacle. The Heat Transfer Engineering Data (4th revised edition, The Japan Society of Mechanical Engineers, 1986) includes data on the radiation factor for aluminum in Figure 1(a), page 184. It indicates a range of 0.01 to 0.05. We adopted 0.1 to stay conservative. To carry out the analysis with a symmetric model, radiosity was used.
(4) Symmetry boundary condition Symmetric surfaces are handled as a heat insulating condition. Surfaces for which no condition is specified are handled as heat insulating conditions in the heat transfer analyses.
(5) Initial temperature condition The analysis should be started with the object to be analyzed which has a uniform temperature of 38°C under normal and accident conditions. In our analysis for integrating thermal test results using a prototype, the analysis was started for a state of uniform temperature of 25°C in order to ensure accord with the initial temperature for the thermal test.
II - B.App2 - 8
Table II-B.App2-2: Thermal Boundary Conditions Radiation through the air in Heat transfer through Radiation through packaging voids Inflow of solar Radiation by flames surrounding air surrounding air (outer recept. internal surface Conditions radiation (heat transfer by (heat transfer condition (heat transfer by inner recpt. outer surface (heat flux defined) radiation defined) defined) radiation defined) inner recept. internal surface
? outer surface)
Ongoing ON OFF ON OFF ON (=0.)
fire Surrounding air: measured Conditions of the ( of flame=0.9 temperature prototype of packaging outer Coefficient of heat transfer surface=0.8)
=10 Natural ON OFF ON cooling Surrounding air: room ( of packaging after fire temperature outer surface =0.1)
Temperature-dependent coefficient of heat transfer II - B.App2 - 9
3.3. Flow of Analysis Fig. II-B.App2-4 shows the flow of the analysis.
Preparations for analyses:
Modeling Specifying material constants Specifying boundary conditions Equation solution (fire)
Modifying boundary conditions Equation solution (natural cooling)
Treatment of results including O-ring positions and temperature records END Fig. II-B.App2-4: Flow of Analysis for Integrating Thermal Test Results
- 4. Analytical Model Since the package to be analyzed has a symmetric shape, our analysis concerns a modeled quarter symmetric zone (hatched zone in Fig. II-B.App2-5) of the package. Our modeling excluded small parts of the packaging because they were regarded negligible in terms of thermal consequences.
A quarter zone was modeled Fig. II-B.App2-5: Modeled Zone for 3-Dimensional Analysis II - B.App2 - 10
By design, the outer receptacle lid contains no heat insulating material outside the external surfaces of the frames and on the six recesses (including the four at the corners on which lifting attachments are provided) which can be engaged with the legs of another outer receptacle when stacked. The preliminary examinations revealed that these recesses of the outer receptacle do not affect the temperature distribution in the inner receptacle.
Thus, we excluded from our analysis those portions of the lid of the outer receptacle which are located outside the frames. The model is all the more conservative because it has contiguous stacking recesses for the legs of another outer receptacle on the lid of the outer receptacle and contiguous bolt seats on the body of the outer receptacle.
In the mechanical prototype tests, the honeycomb elements were slightly deformed but not completely crushed. To avoid reducing our conservatism, the honeycomb elements were assumed to be free from deformation and form heat conduction paths to the inner receptacle.
II - B.App2 - 11
As described in section 3.1 Geometrical Modeling, a zone (triangular pyramid) of the model adopted was cut off in a simple manner to simulate the actual shape of the package subjected to several drop tests.
Moreover, the analytical model was simplified in external dimensions to increase the conservatism and reduce the model scale. As a result, most of the verified deformations (in number and volume) are included in the simplified zone. Fig. II-B.App2-6 shows the resulting analytical model. Figs. II-B.App2-7 to II-B.App2-10 show cutaway images of this damage model. The adopted quarter symmetric model corresponds to a full model with four damaged zones. This partial compressing would contribute to increasing the volumetric insulating property, but the geometrical model simply has a cutaway portion and conserves its original thermal characteristics to maintain the conservatism.
The zone corresponding to contents (loaded pellet storage box assemblies) was assumed to be homogenized.
(a) View from -Y direction (b) View from +Y direction Fig. II-B.App2-6: General View of Analytical Model (entire damage mode)
II - B.App2 - 12
Fig. II-B.App2-7: Cutaway Image of Damage Model (1/4)
Fig. II-B.App2-8: Cutaway Image of Damage Model (2/4) (view from )
II - B.App2 - 13
Fig. II-B.App2-9: Cutaway Image of Damage Model (3/4) (view from )
Fig. II-B.App2-10: Cutaway Image of Damage Model (4/4) (view from )
II - B.App2 - 14
The analytical model is embraced by three elements created for analyzing heat transfer through air, heat transfer by radiation during natural cooling and heat transfer by radiation of flames, respectively. Heat transfer by radiation is taken into account for the border between the internal air and the surrounding constructions.
The finite element model was created in the same way as that for the no-damage analytical model. The model has 102,279 nodes and 125,973 finite elements. Figs. II-B.App2-11 to II-B.App2-13 show the finite element models used.
Fig. II-B.App2-11: Finite Element Model (entire)
II - B.App2 - 15
Fig. II-B.App2-12: Finite Element Model (segment for calculating surface effect)
Fig. II-B.App2-13: Finite Element Model (segment for calculating surface effect and internal radiation)
II - B.App2 - 16
- 5. Physical Properties of Materials (1) Thermal properties of contents The prototype packaging contains weight-simulating lead rods instead of pellets of uranium oxides. Therefore, the analysis for integrating thermal test results took into account thermophysical properties of lead.
The pellet storage box assemblies (contents) have no leaktightness and thus are not affected by rise of the inner pressure resulting from temperature rise. Moreover, the uranium oxides (pellets), nuclear fuel, and the component materials of the pellet storage box assembly are negligible in terms of fusion, gasification or gas leakage resulting from temperature rise. Thus, it is almost needless to determine temperature distribution in the contents. Thus, the analytical model contains a homogenized zone which represents the contents of the packaging. We used equivalent thermophysical property values which had been determined from volumetric ratios of the component materials/substances.
The densities and coefficients of heat transfer for these materials/substances were determined by summing the thermophysical property values multiplied by their volumetric ratios. The specific heat values were determined with the equation ici/ (i and cip are density and specific heat of a material/substance and is average density). Table II-B.App2-3 shows the thermophysical properties of the contents used for the analysis.
(2) Thermophysical properties of aluminum honeycomb element The honeycombs element has an appearance shown in Fig. II-B.App2-14. The honeycomb element literally resembles the periodical pattern of bees cells in structure. Therefore, the honeycomb element, a heat conducting body, can be handled as a homogenized material which has thermophysical properties equivalent to those of these different materials/substances. However, it should be noted that it has specific heat conducting characteristics depending on the directionality.
Fig. II-B.App2-14: Structure of Aluminum Honeycomb Element II - B.App2 - 17
A reference (N. Ogasawara, M. Shiratori, Yu Qiang and T. Kurahara, Evaluation of coefficient of orthotropic heat transfer of honeycomb material, report No. 99-0011, Bulletin (Title B) of The Japan Society of Mechanical Engineers, vol. 65, issue 639, 1999-11) presents an equation for determining the coefficients of heat transfer for different directions of this structure:
x air al R y air 3 al R 2
z air 8 R 3 al R t s
For our analysis, the coefficients of heat transfer x, y, and z were defined with account taken of the orientations of the installed honeycomb material and the directionality depending on their location.
The equivalent density and the equivalent specific heat were determined as follows:
air 8 3 al R C C air air 8 3C al al R Table II-B.App2-4 shows the thermophysical properties of the aluminum honeycomb element used for the analysis.
(3) Thermophysical properties of insulator The values of the thermophysical properties of the insulator used for our preliminary analysis conservatively exceed those published by the manufacturer. Initial results of the preliminary analysis were found incompatible with the results of the preceding thermal test. Further examination using the manufacturers data which we slightly complemented on thermophysical properties led to results compatible with those of the thermal test. The definitive results of the preliminary analysis are conservative. Accordingly, the analytical model achieved is conservative as well and has high compatibility with the results of the thermal test. Table II-B.App2-5 shows the thermophysical properties of the insulator.
(4) Thermophysical properties of other component materials Table II-B.App2-6 shows the thermophysical properties of component materials other than the insulator.
(5) Determining coefficient of heat transfer The coefficient of heat transfer between the external surface of the outer receptacle and the surrounding fluid under fire conditions used for the analysis was 10W/(m2°C), value retrieved from the IAEA transport regulations TS-G1.1 728.30.
II - B.App2 - 18
The coefficient of heat transfer for other conditions was regarded as function Nusselt number:
Nu l : heat conductivity, lrepresentative length (outer receptacle height exc. legs : 0.915 m The Nusselt number was calculated with the formula shown in the IAEA transport regulations TS-G1.1 728.31:
Nu 0.13PrGr 1 3 where Prandtl number Pr = / (: kinetic viscosity; : coefficient of thermal diffusivity (=/c); : density; c: specific heat)
Grashof number Gr = g (Tw - T) I3/ 2 (g: gravitational acceleration; : coefficient of volumetric expansion; Tw: wall temperature; T: air temperature)
Table II-B.App2-7 shows the calculated coefficients of heat transfer.
Table II-B.App2-3: Thermophysical Properties of Contents Heat Heat Temperat Specific Temperat Specific Density conductiv Density conductiv ure heat ure heat (g/cm3) ity (g/cm3) ity (K) (J/kgK) (K) (J/kgK)
(W/mK) (W/mK) 293 3.799 402 9.33 693 3.668 459 9.85 313 3.794 402 9.33 713 3.660 463 9.90 333 3.789 404 9.33 733 3.652 467 9.95 353 3.783 405 9.34 753 3.644 471 10.00 373 3.778 407 9.35 773 3.635 474 10.06 393 3.772 409 9.36 793 3.626 478 10.11 413 3.766 411 9.38 813 3.618 481 10.17 433 3.760 414 9.40 833 3.609 484 10.23 453 3.754 416 9.42 853 3.600 487 10.29 473 3.748 419 9.44 873 3.590 490 10.36 493 3.741 422 9.47 893 3.581 493 10.42 513 3.735 426 9.50 913 3.571 495 10.49 533 3.728 429 9.53 933 3.561 498 10.56 553 3.721 433 9.56 953 3.552 499 10.63 573 3.714 436 9.60 973 3.542 501 10.70 593 3.707 440 9.63 993 3.531 502 10.77 613 3.699 444 9.67 1013 3.521 503 10.85 633 3.692 448 9.71 1033 3.511 504 10.92 653 3.684 452 9.76 1053 3.500 504 11.00 673 3.676 455 9.80 1073 3.489 504 11.08 II - B.App2 - 19
Table II-B.App2-4: Thermophysical Properties of Aluminum Honeycomb Element Specific Heat conductivity (W/mK)
Temperature Density heat (K) (g/cm3) X Y Z (J/kgK) 300 0.0776 907 2.554 3.818 6.767 320 0.0775 921 2.552 3.814 6.759 340 0.0774 934 2.550 3.810 6.751 360 0.0772 946 2.548 3.806 6.743 380 0.0771 957 2.546 3.802 6.735 400 0.0770 966 2.543 3.798 6.727 420 0.0768 975 2.541 3.794 6.719 440 0.0767 983 2.539 3.790 6.711 460 0.0766 991 2.537 3.786 6.702 480 0.0765 998 2.534 3.782 6.694 500 0.0764 1005 2.532 3.778 6.686 550 0.0760 1022 2.526 3.768 6.665 600 0.0757 1040 2.520 3.758 6.645 650 0.0754 1060 2.491 3.712 6.562 700 0.0750 1083 2.462 3.667 6.480 800 0.0743 1140 2.404 3.577 6.315 900 0.0734 1213 2.345 3.487 6.150 1000 0.0725 1300 2.286 3.395 5.984 1100 0.0715 1391 2.226 3.304 5.817 Table II-B.App2-5: Thermophysical Properties of Insulating Material Heat Temperature Density Specific heat conductivity (K) (g/cm3) (J/kgK) (W/mK) 291 0.16 1050 0.031 373 0.16 1050 0.036 473 0.16 1050 0.044 573 0.16 1050 0.053 673 0.16 1050 0.064 773 0.16 1050 0.081 873 0.16 1050 0.098 973 0.16 1050 0.120 1073 0.16 1050 0.145 1173 0.16 1050 0.173 Note: These data are cited from the technical data published by the manufacturer with some modifications.
II - B.App2 - 20
Table II-B.App2-6: Thermophysical Properties of Component Materials Adopted for Thermal Analyses Specific Heat Temperature Density Component Material heat conductivity (K) (g/cm3) (W/mK)
(J/kgK) 300 7.92 449 16.0 400 7.89 511 16.5 Inner/Outer Receptacle Stainless steel (1) 600 7.81 556 19.0 800 7.73 620 22.5 1000 7.64 644 25.7 Fire-resistant rubber (2) 300 0.86 2200 0.36 Silicone rubber 293 0.97 1600 0.20 Rubbers 400 0.97 1500 0.19 Neoprene rubber 293 1.23 2200 0.25 400 1.23 2200 0.23 Notes: (1) Heat Transfer Engineering Data, 4th revised edition, JSME, 1986 (2) The properties of ethylene propylene rubber (main component) are substituted.
Table II-B.App2-7: Coefficients of Heat Transfer Coefficient of Coefficient of Temperature Temperature heat transfer heat transfer (K) (K)
(W/m2K) (W/m2K) 311 0 550 7.942 320 3.858 600 7.988 340 5.460 650 7.975 360 6.250 700 7.965 380 6.742 800 7.878 400 7.082 900 7.783 420 7.326 1000 7.619 440 7.509 1100 7.448 460 7.643 1200 7.273 480 7.748 1500 6.758 500 7.826 II - B.App2 - 21
- 6. Results of Analysis for Integrating Thermal Test Results Figs. II-B.App2-15 shows the results of the analysis for integrating thermal test results. Figs. II-B.App2-16 to II-B.App2-19 show contour diagrams for the model at the moment of thermal test completion and at the moment when the highest temperature was attained in the inner receptacle flange.
The analysis was carried out to evaluate the points of the model which correspond to the different locations of the inner and outer receptacle flanges on which temperatures had been measured during the thermal test.
Good accord is observed between the temperature fluctuations of these flange points and those indicated in Fig. II-B.App2-3: Evolutions of Temperatures (1/2) and Fig. II-B.App2-3: Evolutions of Temperatures (2/2). More precise comparison of the analysis results with the test results revealed that the former is 8 to 10 percent more conservative for the flange points of the inner receptacle and 4 to 14 percent more conservative for the flange points of the outer receptacle than the latter. Table II-B.App2-8 shows the highest temperatures on these flange points calculated in comparison with the real measurements. The temperature variation between the analysis and the test is greater for the flange points of the outer receptacle than for those of the inner receptacle. Since the analysis for integrating thermal test results was focused on the reactions in the inner receptacle, we concluded that an analytical model compatible with the thermal test results was created, keeping a higher conservatism over the thermal test results. Thus, we are ready for carrying out thermal analyses of the prototype package under normal and accident conditions of transport.
Fig. II-B.App2-15: Results of Analysis for Integrating Thermal Test Results II - B.App2 - 22
Table II-B.App2-8: Highest Temperatures Compared between Test Results and Analysis Results Inner Receptacle Flange Outer Receptacle Flange Narrower Corner Wider Narrower Corner Wider Test Results 141.9 143.7 127.1 394.6 343.8 407.1 Analysis Results 155.5 155.3 138.8 449.0 381.4 423.9 Increase 9.6% 8.1% 9.2% 13.8% 10.9% 4.1%
II - B.App2 - 23
Fig. II-B.App2-16: Temperature Distribution in the Entire Packaging at End of Thermal Test (unit: K)
O-ring Fig. II-B.App2-17: Temperature Distribution in Rubber near O-ring at End of Thermal Test (unit: K)
II - B.App2 - 24
Fig. II-B.App2-18: Temperature Distribution in Entire Package (when the highest temperature was attained in O-ring; unit: K)
O-ring Fig. II-B.App2-19: Temperature Distribution in Rubber near O-ring (when the highest temperature was attained in O-ring; unit: K)
II - B.App2 - 25
II-C. Leaktightness Analysis C.1. General The type GP-01 transport packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without being dismantled. The inner receptacle is designed to contain two pellet storage box assemblies (contents). The outer receptacle has the principal function of protecting the inner receptacle which forms the containment boundary of the package.
The inner receptacle includes an upper lid which allows pellet storage box assemblies to be loaded and retrieved vertically while it is opened. The lid is joined to the body of the inner receptacle by means of rod bolts. An O-ring is provided for sealing on the flange surface.
The packaging is designed to store two assemblies of pellet storage boxes which contain pellets (minimum elements of nuclear fuel) of uranium oxides. To construct an assembly, pellet storage boxes are stacked alternately with partitions which are penetrated by six pillars. The stack of pellet storage boxes is fixed with nuts at the threaded top of the pillars. Pellets are ceramic non-dissipative solids prepared by press-molding and sintering (at higher than 1000°C) process. This packaging is not designed to contain nuclear fuel materials in liquid or gaseous phase.
In the containment boundary formed by the inner receptacle, the pellet storage box assemblies have no gaps which might cause pellets to leak out from the pellet storage boxes, and have a rigid structure.
(1) Normal conditions of transport Packages configured with the type GP-01 packaging are classified as type A packages. This chapter will describe how radioactive materials or substances do not leak from the package under normal conditions of transport according to the Regulations, Article 9.
(2) Accident conditions of transport Packages configured with the type GP-01 packaging do not need to have the leaktightness required by the Regulations under accident conditions of transport. This chapter will describe how radioactive materials or substances are contained in the inner receptacle forming the containment boundary under accident conditions of transport.
C.2. Containment System C.2.1. General The inner receptacle of the package consists of a lid and a main body. The lid consists of a monolithic stainless steel plate 10 mm in thickness and the main body is composed of stainless steel plates 6 to 8 mm in thickness, welded in the form of a box. Stainless steel plates 12 mm in thickness are machined and welded as flanges onto the upper part of the body of the inner receptacle. All the joints contributing to the containment boundary are finished with continuous welding.
A silicone rubber O-ring 10 mm in diameter is provided at the interface of the body and the lid of the inner receptacle which are joined by means of rod bolts to ensure leaktightness of the inner receptacle.
II - C - 1
The entire finished inner receptacle is inspected for leaktightness in water at least one meter in depth or under an equivalent hydraulic pressure for at least one hour.
C.2.2. Penetrations in Containment System The lid covers the entire top surface of the inner receptacle which forms the containment system for pellet storage box assemblies, contents of the package. The containment boundary is completed with sixteen (16) rod bolts for firmly tightening the lid on the body of the inner receptacle. The type GP-01 packaging is not designed for containing liquids or gases and has no valves, and there are no penetrations.
C.2.3. Gasket and welds of containment system The material (silicone rubber) of the O-ring provided on the inner receptacle flange maintains its thermal strength in a temperature range from -40°C to +38°C. Deterioration does not occur in the material in the temperature range of -40°C to +38°C. The inner receptacle of the packaging is constructed by continuous welding of stainless steel plates which are not liable to deformations that might affect its leaktightness or confinement.
Loading of contents is performed at room temperature and under room atmospheric pressure. Thus, no pressure differences will be generated between the interior and the exterior of the inner receptacle, and loading operations will not affect the performance of the O-ring and the welds of the inner receptacle.
C.2.4. Lid of inner receptacle The lid of the inner receptacle consists of one single stainless steel plate 10 mm in thickness. Sixteen (16) rod bolts are used to join the lid to the main body of the inner receptacle to create a containment boundary.
Under normal conditions of transport, the leaktightness of the inner receptacle is maintained by the lid firmly joined to the body by means of rod bolts.
Packages configured with the Type GP-01 packaging are classified as type A fissile transport packages and do not need to meet the regulatory requirements for leaktightness under accident conditions of transport. The firm connection of the lid with the body of the inner receptacle thus maintained by the rod bolts contributes to containing pellet storage box assemblies in the inner receptacle.
C.3. Normal Conditions of Transport As described in section A.5.7. Summary of results and evaluation, the evaluation of the package under normal conditions of transport has revealed that the leaktightness of the inner receptacle keeps radioactive materials/substances in its substantial containment system and prevents them from leaking out.
(1) Thermal test Packages configured with the Type GP-01 packaging are categorized as type A fissile packages and do not need to undergo regulatory thermal tests. As presented in section B.4.6. Summary of Results and Evaluation, a thermal analysis showed that the temperature in the O-ring attains 68°C. This level is, however, far below the service temperature (180°C) for the material of the O-ring. Therefore, the material of the O-ring will not deteriorate at such temperatures. The average temperature inside inner receptacle is 59°C. The analysis proved II - C - 2
that all the materials of the inner receptacle will maintain their performance integrity even if the inner pressure in the inner receptacle is increased by a temperature rise in the surrounding atmosphere. Thus, the thermal test will not affect the leaktightness of the package.
(2) Water Spraying As described in section A.5.2. Water Spray Test, the main structural materials of the packaging are stainless steel and will not deteriorate in water. Moreover, the packaging has a structure which prevents water from entering the interior of the package. Water spraying will not affect the leaktightness of the package.
(3) Free Drop Tests As described in section A.5.3.1. Prototype tests, a free drop will cause local deformation in the outer receptacle.
Nevertheless, the containment boundary of the package was maintained (see section A.5.3.2. Integrity of containment boundary). Thus, free drop will not affect the leaktightness of the containment boundary of the package.
(4) Stacking Test As described in section A.5.4. Stacking Test, the load applied to the package during the stacking test was far below the allowable highest stress which might be generated on the package. Thus, the package/packaging will not be deformed. Since the inner receptacle does not support any part of the load generated during the stacking test, the leaktightness of the inner receptacle will not be affected.
(5) Penetration Tests As explained in section A.5.5. Penetrations, the test rod for the penetration test will not penetrate the outer plates of the outer receptacle.
C.3.1. Leakage of Radioactive Materials The results of the prototype tests and the structural analyses have revealed that the inner receptacle maintains its leaktightness under normal conditions of transport and that no leakage of radioactive materials from the inner receptacle will occur.
C.3.2. Rise of pressure in containment system The temperature of the inner receptacle may reach 75°C in an environment of solar radiation. At this temperature, no gases will be emitted from any of the materials including rubber and stainless steel of the inner receptacle, or from the pellets of uranium oxides. The only possible rise of pressure in the containment system is that which may result from a temperature rise of the atmosphere (air) in the inner pressure. As shown in section A.5.1.3. Calculation of stresses, any rise of the inner pressure resulting from temperature rise will not affect the performance integrity of the inner receptacle.
C.3.3. Contamination of Coolant The package/packaging contains no coolant (cooling material or agent). Thus, no contamination of coolant II - C - 3
(cooling material or agent) will occur.
C.3.4. Loss of Coolant The package/packaging contains no coolant (cooling material or agent). Thus, no loss of coolant or cooling (cooling material or agent) will occur.
C.4. Accident Conditions of Transport Packages configured with the type GP-01 packaging, type A fissile packages, do not need to meet the regulatory requirements for leaktightness under accident conditions of transport. Our tests and analyses have shown that the contents will be maintained in the package, and that none of the contents will leak from the package under accident conditions of transport. The following paragraphs summarize the results of the test and analysis of the package under accident conditions of transport.
(1) Drop I tests As shown in section A.9.2.1.5. Summary of results of Drop I tests, no cracks, fractures or penetration holes that might affect the interior of the package were generated in the outer receptacle, and the lid did not move from its required position. No cleft or hole was produced in the joints on the flange, so that any exposure of the inner receptacle was prevented.
The lid and body of the inner receptacle were deformed, and some of the rod bolts for tightening the receptacle were deformed. Nevertheless, none of the rod bolts was fractured or separated from the original locations, and the lid did not move from its required position.
The contents, pellet storage box assemblies, remained in the inner receptacle and did not leave their initial required positions. Thus, the pellets of uranium oxides will not leak from the storage boxes.
Prototype tests were conducted under very demanding test conditions for the prototypes: for example, every single prototype was subjected to five drop trials. Throughout the test, the dummy contents were retained in the inner receptacle. All these results show with sufficient conservatism that the inner receptacle will maintain its function of retaining the contents in its leaktight body.
(2) Drop II tests As described in section A.9.2.2.1. Summary of results of Drop II tests, several dents were produced on the external surface of the outer receptacle. No penetration or crack/cleft or hole was generated on its external surfaces. The drop tests did not affect, or produce any deformation to, the internal zones of the outer receptacle, and never affected the inner receptacle or contents.
(3) Thermal test As shown in section B.5.6. Summary of Results and Evaluation, the load applied during the thermal test caused no remarkable deterioration in the package components. Dissolution, inflammation, or deformation resulting from alteration will not occur in the components of the package. The contents will not leave their original locations and will not leak from the package. The temperature of the O-ring on the inner receptacle flange may reach 170°C, far below the maximum service temperature (180°C) of its material (silicone rubber).
II - C - 4
Even if the inner temperature of the inner receptacle reaches 170°C under unfavorable conditions, nuclear fuel materials will not move in the inner receptacle or leak from the containment boundary.
(4) Water immersion Our criticality analysis takes account of entry of water into the inner receptacle. However, the immersion test under 0.9-meter water head as stipulated by the Public Notice was not conducted. Even in case of immersion in water or entry of water into the inner receptacle, the nuclear fuel material will not change its property of insolubility in water. Furthermore, because of this property, no fuel material will be released from the packaging even if such external water flows out from the inner receptacle.
C.4.1. Fission product gases Pellets of unirradiated uranium oxides to be contained in the inner receptacle will not generate any fission product gas.
C.4.2. Leakage of radioactive materials Even under accident conditions of transport, the contents will remain sealed (confined) in the inner receptacle.
C.5. Summary of Results and Evaluation The package has been evaluated for leaktightness under normal conditions of transport. The results of the evaluation prove that the inner receptacle maintains its integrity of containment boundary.
For reference, the leaktightness of the package was evaluated under accident conditions of transport. The results confirmed that the inner receptacle, which is the sealed boundary, was maintained its intergrity and that there were no significant leaks that could affect criticality analysis.
II - C - 5
II-D. Shielding Analysis D.1. General The nuclear fuel material to be contained in the package configured with type GP-01 packaging consists of pellets of unirradiated uranium oxides enriched to 5 weight percent or less. Because of the low source intensity of the contents, the packaging has no special elements or systems designed for shielding.
Most of the radioactive dose from the package is generated by gamma rays emitted as a result of alpha decay and/or beta decay of the uranium and its daughter nuclides.
Our shielding analysis of the package conservatively assumed that the packaging contains 264 kg of uranium oxides enriched to 5 weight percent, a value which corresponds to the highest source intensity. The dose equivalent rates of the package under routine conditions of transport and under normal conditions of transport were determined with the code of the QAD-CGGP2R point nuclear attenuation integration program. This code can be useful in determining the effective dose equivalents adopted in the Japanese internal laws/ordinances and regulations under the ICRP Recommendations 1990 (Publication 74). The following assumptions were applied to the analysis:
264 kg of uranium oxides is homogeneously contained in the space of the inner receptacle; Stainless steel is the principal structural material of the inner and outer receptacle of the package; The analytical model of transport package under normal conditions of transport includes a portion corresponding to the outer receptacle which has a 5-mm reduced length, width and height; Only uranium oxides are present in the source range, and conservatively, the pellet storage box assemblies (including the pellet storage boxes) and the boronic stainless steel plates are assumed to be absent; The ORIGEN 2 code is used to determine the source intensity, account taken of the daughter nuclides of the uranium.
Table II-D-1 shows the results of the calculation performed on the above analysis assumptions. The highest dose equivalent rate determined for the package surface under routine conditions of transport is 2.80 10-2 mSv/h and the highest dose equivalent rate determined for any locations at 1 meter from the package surface is 2.56 Sv/h. These results meet the requirements: 2 mSv/h or less for the package surface and 100 Sv/h or less at 1 meter from the package surface.
The highest dose equivalent rate determined for the package surface under normal conditions of transport is 3.26 10-2 mSv/h, a value which is within the requirement: 2 mSv/h or less for the package surface. The increment in the dose equivalent rate under normal conditions of transport was 17 percent.
II - D - 1
Table II-D-1: Highest Dose Equivalent Rates for Package 1 m from Package On Package Surface Surface Routine conditions of 2.80 10-2 mSv/h 2.56 Sv/h transport Requirement 2 mSv/h 100 Sv/h Under normal 3.26 10-2 mSv/h -------------
conditions of transport Requirement 2 mSv/h -------------
D.2. Requirements for Radiation Source The package has a maximum capacity of 264 kg of uranium oxides. Since the uranium oxides are contained within the containment boundary of the inner receptacle, the analytical models are based on the assumption that a radiation source represented by 264 kg of uranium oxides is homogeneously contained in the inner receptacle.
D.2.1. Gamma ray source The contents of the package are unirradiated uranium oxides enriched to 5 weight percent or less. The major nuclides are 232U, 234U, 235U, 236U, 238U, and 99Tc. The detailed characteristics of the source are shown below.
(1) Radioactive materials contained in the contents The radioactive materials of the contents of the package being considered are the six kinds of nuclides: 232U, 234U, 235U, 236U, 238U, and 99Tc. The composition of the materials is 232U at 1.0 10-8 weight percent, 234U at 5.0 10-2 weight percent, 235U at 5.0 weight percent, 236U at 2.5 10-2 weight percent, 99Tc 1.0 10-6 weight percent, and 238U at the remaining ratio.
(2) Source intensity The ORIGEN 2 code was applied to determine the gamma ray source spectra and the radioactivities of the radioactive materials referred to in D.2.1(1) and their daughter nuclides for a cooling time of 10 years before equilibrium. Table II-D-2 shows the results of the calculation of the gamma ray source spectra. Table II-D-3 shows the results of calculation of the radioactivities. For details of the ORIGEN 2 code, refer to Appendix 1 to Chapter II-D.
II - D - 2
D.2.2. Neutron source Not applicable.
Table II-D-2: Calculated Gamma Ray Spectra of Uranium Oxides per 264 kg Average Gamma Ray Energy Source Spectrum (MeV) (photons/s) 0.01 6.376 109 0.025 4.440 108 0.0375 1.999 108 0.0575 4.417 108 0.085 5.190 108 0.125 2.837 108 0.225 6.788 108 0.375 7.184 107 0.575 4.431 107 0.85 2.760 107 1.25 1.758 107 1.75 3.249 106 2.25 1.235 103 2.75 5.706 106 3.5 4.031 102 5 1.719 102 7 1.973 101 9.5 2.264 100 Table II-D-3: Calculated Radioactivities of Uranium Oxides (per 264 kg) 232U 234U 235U 236U 238U 99Tc Total Radioactivity 1.34 108 2.70 1010 1.87 109 1.40 108 8.26 109 1.46 106 3.75 1010 (Bq)
II - D - 3
D.3. Characteristics of Analytical Models D.3.1. Analytical Models D.3.1.1. Routine conditions of transport Fig. II-D-1 shows the analytical model used. The type GP-01 packaging has a nested-box construction consisting of an inner receptacle and an outer receptacle. The inner receptacle is designed for containing pellet storage box assemblies composed of stacked flat boxes which contain uranium oxides as nuclear fuel, and boronic stainless steel plates around these assemblies. The outer receptacle is filled with pieces of a ceramic fiber insulating material. Aluminum honeycomb elements are inserted as shock absorbers between the outer receptacle and the inner receptacle.
The analytical model for shielding analysis corresponds to the stainless steel plates of the inner and outer receptacle, the principal components of the packaging. The outer receptacle is modeled as a rectangular cuboid (parallelepiped) 1134 mm in length, 850 mm in width and 920 mm in height (outer dimensions). The inner receptacle also is modeled as a rectangular cuboid (parallelepiped) 924 mm in length, 610 mm in width and 685 mm in height. The insulator and the shock absorbers are excluded.
The source range is modeled on the assumption that 264 kg of uranium oxides is present as a homogeneous mass in the inner receptacle. The stainless steel components of the pellet storage box assemblies and the boronic stainless steel plates are excluded.
We selected an evaluation point on the package surface and another at one meter from the package surface.
D.3.1.2. Normal conditions of transport Fig. II-D-2 shows the analytical model for normal conditions of transport.
As described in section A.5.7, the transport packagings were not deformed significantly. The deformations produced during the mechanical strength tests were smaller than 5 mm. The deformations caused during the drop tests of one (Prototype No. 2) of the specimens positioned in an orientation which would cause maximum damage to the package were ignored, since the deformations were local and did not intersect or contain the location corresponding to the highest dose equivalent rate.
Thus, the analytical model adopted for our shielding analysis was conservatively modeled as one reduced by 5 mm in all the three dimension of the outer plates of the outer receptacle as compared to the analytical model for routine conditions of transport.
The model includes a zone corresponding to shock absorbers which were assumed to have been totally crushed. Moreover, the model is based on the assumption that the inner receptacle containing the source range has been moved to and stays in contact with the internal surface of the outer receptacle. This model is conservative partly in this respect: the source range has approached the external surface of the entire package.
II - D - 4
Unit: mm (PLAN) 3 Outer receptacle (outer plate) 3 2 Outer receptacle (inner plate) 2 8 Inner receptacle 6
820 Source range 610 459 772 924 1134 (ELEVATION) 3 Outer receptacle (outer plate) 2 Outer receptacle (inner plate) 10 Inner receptacle 920 685 Source range 571 6
2 3
Packaging (stainless steel)
Source range (uranium oxides)
Evaluation point (surface)
Evaluation point (1 m from surface)
Fig. II-D-1: Analytical Model of Package under Routine Conditions of Transport II - D - 5
Unit: mm (PLAN) 3 Outer receptacle (outer plate) 3 2 Outer receptacle (inner plate) 2 8 Inner receptacle 6
815 610 Source range 459 5 mm reduced dimension in relation to the analytical model for routine conditions of transport 772 924 1129 (ELEVATION) 3 Outer receptacle (outer plate) 2 Outer receptacle (inner plate) 10 Inner receptacle 915 685 Source range 571 6 (thickness of bottom plate of inner receptacle) 2 (thickness of bottom plate of 5 mm reduced dimension in relation to the analytical model under 3 outer receptacle inner plate) routine conditions of transport Packaging (stainless steel)
Source range (uranium oxides)
Evaluation point (surface)
Evaluation point (1 m from surface)
Fig. II-D-2: Analytical Model for Shielding Analysis of Package under Normal Conditions of Transport II - D - 6
D.3.2. Density of Atoms in Various Zones of Analytical Model The analytical model for shielding analysis consists of a packaging zone and a source range. Table II-D-4 shows the densities and components of these zones, the numbers of atoms in the components, and the volume ratios.
All zones other than the source and the package were regarded as air for purposes of calculations.
Table II-D-4: Densities and Components of Zones, Numbers of Atoms in Components, and Volume Ratios Density Density of atoms Zone Component Volume Ratio (g/cm3) (atoms/barncm)
Source range U 3.15 10-3 1.41 1.0 (uranium oxides) O 6.30 10-3 Fe 5.66 10-2 Cr 1.83 10-2 Packaging 7.90 Ni 8.51 10-3 1.0 (stainless steel)
Si 1.69 10-3 Mn 1.73 10-3
- Note: This value has been determined from the value (7.93 g/cm3) of density for SUS 304 shown in the Standard JIS G 4305.
II - D - 7
D.4. Shielding Evaluation D.4.1. Method The analytical models shown in Figs. II-D-1 and II-D-2 were subjected to a shielding analysis on the QAD-CGGP2R code, which is a point nuclear attenuation integration program. The program includes data such as coefficients of attenuation and coefficients of regeneration as libraries. This code includes also factors for converting into absorbed dose in air and correction factors for simpler and more efficient conversions of absorbed dose in air into dose equivalent rates.
These coefficients should be used in order to determine the effective dose equivalent defined in the laws and regulations currently in force in Japan which have adopted the ICRP Recommendations 1990 (Publication 74).
For details of the QAD-CGGP2R code, refer to Appendix 2 to Chapter II-D.
D.4.2. Results of evaluation Table II-D-5 shows the results of the evaluation of a package which contains 264 kg of unirradiated uranium oxides enriched to 5 weight percent. The highest value of dose equivalent rate on the package surface was obtained for the package bottom surface under both routine conditions of transport and normal conditions of transport. The highest value at one meter from the package surface was obtained on one of the package lateral surfaces. It should be noted that these evaluation values were determined on the basis of a preliminary survey of the evaluation points which were likely to present the highest value.
For details of the results of a preliminary survey of the points which were likely to present the highest value, refer to Appendix 3 to Chapter II-D.
Table II-D-5: Results of Shielding Analysis Normal Conditions of Routine Conditions of Transport Evaluated Transport Surface 1 m from package On package surface On package surface surface Bottom 2.80 10-2 mSv/h 2.37 Sv/h 3.26 10-2 mSv/h Lateral 2.51 10-2 mSv/h 2.56 Sv/h 3.19 10-2 mSv/h Thus, the highest dose equivalent rates on the package surface and at one meter from the package surface were found to be within the stipulated permissible ranges. The increase in dose equivalent rate under routine conditions of transport and under normal conditions of transport was 17 percent.
II - D - 8
D.5. Summary of Results and Evaluation The package was analyzed for shielding capability under routine conditions of transport and under normal conditions of transport. As shown in Table II-D-1, the highest dose equivalent rate under these conditions does not exceed the values stipulated in the applicable laws/ordinances and regulations. Thus, the type GP-01 transport packaging has sufficient shielding capability.
References
- International Commission on Radiological Protection, Conversion Coefficients for Use in Radiological Protection Against External Radiation: ICRP Publication 74, 1996.
- Y. Sakamoto and S. Tanaka, QAD-CGGP2 AND G33-GP2: Revised Versions of QAD-CGGP and G33-GP, JAERI-M 90-110 (1990).
- S. B. Ludwig and A.G. Croff, Revision to ORIGEN2-Version 2.2, transmittal memo of CCC-0371/17, Oak Ridge National Laboratory, 2002.
II - D - 9
Appendix 1 to Chapter II-D Description of ORIGEN 2 Code The ORIGEN code was first developed by researchers from Oak Ridge National Laboratory, USA, in 1973 for calculating the composition, radioactivity and calorific value of fission products, actinides and structural materials.
Generally, the generation and decay process of a nuclide is defined as follows:
N N dXi / dt lij j X j f ik k X k ( j i ) X i (1) j1 K 1 (i-1,..., N)
X i : number of nuclides i (atom density)
N : number of nuclides l i j : ratio of nuclides j which decay and generate nuclides i to total number of nuclides j j : decay constant for nuclide j X j : number of nuclides j which decay and generate nuclides i
- neutron flux, averaged for position and energy f ik: rate of generation of nuclides i generated by nuclides k by absorbing neutrons k : neutron absorption cross section of nuclide k, averaged for spectrum X k : number of nuclides k i : decay constant for nuclide i i : neutron absorption cross section of nuclide i.
When the value remains constant despite the variation of the atom density X of the nuclide within a short period of time, equation (1) takes the form of simultaneous linear normal differential equation as follows:
XA X (2)
In equation (2), X is a vector which has a component Xi, A is a constant matrix.
Equation (2) is solved X( t ) exp(A t ) X(0) (3) where exp( A t ) is (A t ) m exp(A t )
(4) m 0 m!
This method of solving is known as the matrix exponential method. The method makes it possible to first determine numerically the right term of equation (4) and determine, using the initial condition X(0), the atom density X at the time t with equation (3).
For nuclides which have a short life, Batemans formula, analytical solution of equation (1) is used in parallel.
II - D.App1 - 1
The ORIGEN code has the following versions:
ORIGEN-73: original program ORIGEN-79: ORIGEN-73 with modified libraries ORIGEN2: ORIGEN-79 with improved calculation processes ORIGEN2-82: ORIGEN2 with modified libraries ORIGEN2-86: ORIGEN2-82 with modified libraries ORIGEN2.1: ORIGEN2-86 to which new libraries were added ORIGEN2.2: ORIGEN2.1, debugged Our shielding analysis was conducted with ORIGEN2.2.
Below is a simplified flowchart of the ORIGEN code:
Inputting Libraries Data Editing Calculating Neutron Flux Calculating short-life nuclides with Batemans Formula Calculating long-life nuclides in the matrix exponential method Outputting the results Flowchart of ORIGEN Code II - D.App1 - 2
X Source Range X/Y-Direction: Top and Bottom Surface and are evaluation points Package Surface on the bottom surface Y
II - D.App1 - 3 Y Y/Z-Direction: X X/Z-Direction: Wider-Narrower-side Surface side Surface Survey ranges for location on and one meter from the package surface Fig. II-D.App-1: Preliminary Survey Ranges for Finding Highest Dose Equivalent Rates on Analytical Model for Analysis of Shielding Capability under Routine Conditions of Transport
Appendix 2 to Chapter II-D Description of QAD-CGGP2R Code
- 1. General The QAD-CGGP2R code is a three-dimensional point nuclear attenuation integration program based on QAD-CG developed by researchers from Los Alamos National Laboratory (LANL), USA, and which was improved by researchers from Japan Atomic Energy Research Institute (JAERI) for determining effective dose.
As of April 1, 2001, values of effective dose must be evaluated in shielding analysis in accordance with the revised laws and regulations relative to the Laws Concerning the Prevention of Radiation Hazards due to Radioisotopes and Others which were published on October 23, 2000, to assimilate the ideas of the ICRP Recommendations 1990.
In general, QAD codes are referred to as point nuclear attenuation methods. A volume source is divided into several micro-volumes. Using such micro-volumes, the attenuation of gamma rays before (until) the calculation point is determined with exponential attenuation of material and inverse-square attenuation of distance. Contributions of scattered rays other than the direct rays are approximated with a gamma ray buildup factor. Contribution of the entire source (ray flux, dose rate, etc.) is determined with the sum of micro-volumes.
- 2. Advantages Point nuclear attenuation methods take into account scattered rays with a gamma ray buildup factor, but not the evolution of energy spectrum and the angle distribution of gamma rays. Thus, the QAD-CGGP2R code has several advantages: three-dimensional shapes can easily be inputted; the method for determining the gamma ray buildup factor is based on a geometrical series equation (G-P method); and dose rates can be determined in accordance with the ICRP Publication 74.
The QAD-CGGP2R code is capable of handling various three-dimensional shapes such as those of source and shielding material: a source can be represented with a combination of three kinds of 3-D figures including circular cylinders, rectangular parallelepipeds and spheres; and a shielding material with a combination of nine kinds of 3-D figures including rectangular parallelepipeds, spheres, circular cylinder solids, oval cylinder solids, circular truncated cones, oval truncated cones, wedge shapes, box shapes and desired hexahedrons.
Input data include specified energy, shape, intensity, number of divisions of a source, specified shape and zone of a system, densities of materials, selected gamma ray buildup factor, and positions of calculation points. In addition to the inputted data, the output data include the flux, air kerma rates, effective doses and 1-cm dose equivalent for various calculation points.
The QAD-CGGP2R code includes the mass absorption coefficients, the exposure buildup coefficients, and the effective value conversion factors required for determining dose rates in accordance with the ICRP Publications 74 and 51.
II - D.App2-1
- 3. Calculation Method The point nuclear attenuation method comprises dividing a volume source which has a finite spread into a number of volume elements (referred to as dose elements). While each of such dose elements is regarded as a point-like source, space integration is conducted to determine their contributions at the calculation points.
Below is the equation for calculating the dose equivalent rate D at the calculation point considered:
jk t k B jk t k , E j f x jk t k , E j S0ij e k D K j k k 2
j i 4ri where, i : subindex for dose element of a source j : subindex for source energy k : subindex for a zone after a space has been divided into zones Kj: absorption dose rate conversion coefficient for energy j in (Gy/hr)/(photons/cm2/sec)
B : gamma ray exposure buildup factor fx : effective value conversion factor S0ij : source intensity for energy j in the source element i in photons/sec jk : dose absorption factor for zone k at energy j in cm-1 Ej : incident energy of the j-th gamma ray in MeV tk : distance traveled by gamma ray in zone k in the space in cm ri : distance from dose element i to the calculation point in cm Gamma ray source Shield (dose absorption factor:
Gamma ray source intensity in the ith cell:
Calculation point(dose equivalent t1 rate: D t2 ri II - D.App2-2
Appendix 3 to Chapter II-D Choosing Evaluation Points for Providing Highest Dose Equivalent Rates A preliminary survey was conducted to choose locations which correspond to the highest dose equivalent rate on the top, bottom, narrower-side and wider-side surfaces of the package, and locations which correspond to the highest dose equivalent rate at positions one meter from those surfaces. From the chosen locations, the evaluation point for shielding analysis which accounts for the highest dose equivalent rate for the entire package was adopted for each of the two distance categories.
Thus, the highest value of dose equivalent rate on the package surface was given on the package bottom surface of the package and at a location one meter from the wider-side surface of the package The following paragraphs summarize how the preliminary survey was conducted.
- 1. Calculating dose equivalent rates on different surfaces of the package (1) Under routine conditions of transport Fig. II-D.App-1 shows the ranges of evaluation points examined during the preliminary survey.
On the survey results, we decided to calculate the dose equivalent rates for the two directions of the line drawn from the source center which intersects every side of the package at right angles. Figs. II-D.App-2 to II-D.App-9 show the results.
These results testify that on each side of the package, the highest dose equivalent rate is given at the point at which a line drawn from the source center intersects the flat surface of the package.
The highest dose equivalent rates shown in Table II-D.App-1 were compared with each other. This comparison revealed that the highest dose equivalent rate was given on the bottom surface and at a location one meter from the wider-side surface.
(2) Under normal conditions of transport Similar calculations to those of the preceding paragraph conducted for the package under normal conditions of transport showed the same tendency. The values shown in Table II-D.App-1 were compared with each other. This comparison showed that of the package surfaces, the bottom surface presented the highest dose equivalent rate.
Table II-D.App-1: Highest Dose Equivalent Rates on Package Surfaces and at Locations 1 m from Package Surfaces Under Normal Under Routine Conditions of Transport Evaluation Conditions of Transport Surface 1 m from Package On Package Surface On Package Surface Surface Top 1.86 10-2 mSv/h 1.88 Sv/h 1.63 10-2 mSv/h Bottom 2.80 10-2 mSv/h 2.37 Sv/h 3.26 10-2 mSv/h Narrower side 2.15 10-2 mSv/h 1.68 Sv/h 3.02 10-2 mSv/h Wider side 2.51 10-2 mSv/h 2.56 Sv/h 3.19 10-2 mSv/h II - D.App3-1
- 2. Conclusion Under routine conditions of transport, the bottom surface presented the highest dose equivalent rate of all the package surfaces: 2.80 10-2 mSv/h. Of the locations one meter from the package surfaces, the 1-meter location corresponding to the wider-side surfaces presented the highest dose equivalent rate: 2.56 Sv/h.
Under normal conditions of transport, the bottom surface presented the highest dose equivalent rate of all the 1-meter locations corresponding to the package surfaces: 3.26 10-2 mSv/h.
II - D.App3-2
II-E. Criticality Analysis E.1. General The type GP-01 transport packaging is designed for use in routine conditions of transport as well as under normal and accident conditions of transport without restriction on the number of packages transported simultaneously. Under these conditions, the packaging will never attain criticality.
(1) Assuming isolated system conditions for package (2) Assuming isolated system conditions for fissile package under normal condutions of transport (3) Assuming isolated system conditions for fissile package under accident test condutions of transport (4) Assuming arrayed system conditions for fissile package under normal condutions of transport (5) Assuming arrayed system conditions for fissile package under accident test condutions of transport Our analysis for subcriticality will concern arrayed system conditions for fissile package under accident test condutions of transport, since this is the most demanding condition for evaluation of the above. Our analysis will use the KENO V.a criticality computing code which is integrated in the SCALE Code System.
E.2. Object Analyzed E.2.1. Contents of Package The packaging is designed to contain two pellet storage box assemblies containing pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium of enrichment of up to 5 weight percent. An as-finished pellet storage box assembly consists of pellet storage boxes stacked alternately with partitions which are penetrated by six pillars. Two types of pellet storage box assembly are available with the type GP-01 packaging:
assembly A composed of twelve (12) pellet storage boxes which can store up to 11 kg of UO2 per box, and assembly B composed of five (5) pellet storage boxes which can store up to 20 kg of UO2 per box. The assembly A has a maximum capacity of 132 kg of UO2 and the assembly B has a maximum capacity of 100 kg of UO2. The packaging has a loading capacity of 264 kg of UO2 pellets in assembly A or 200 kg of UO2 pellets in assembly B.
The characteristics of the contents of the package are not altered under normal and accident conditions of transport. The contents are liable only to small alterations in shape under normal conditions of transport, and such alterations are included among those that are expected to occur under accident conditions of transport.
The contents suffer no visible alterations in shape under accident conditions of transport during the thermal test or water immersion test. The contents suffer several alterations in shape during the drop tests:
- The pillars and nuts in the pellet storage box assemblies are not damaged, and the shape of the pellet storage boxes and the spacing of the partitions are maintained;
- The positioning blocks for retaining pellet storage boxes and the positioning block brackets are not fractured or significantly deformed, and the pellet storage boxes are retained inside the effective range of positioning blocks;
- The main portions and lids of pellet storage boxes do not present clefts or openings that might form routes for leakage of pellets to the exterior, and the nuclear fuel material remains in the pellet storage boxes; II - E - 1
- Results of rod drop test demonstrated that the test drop impact will not seriously affect the containment of the pellets; nevertheless, the possibility of pellet fracture cannot be excluded.
E.2.2. Packaging The type GP-01 packaging consists of an outer receptacle and an inner receptacle which can be retrieved from the outer receptacle without being dismantled like a nested box. In the routine conditions of transport, one inner receptacle is loaded in the outer receptacle. The inner receptacle is designed to contain two pellet storage box assemblies (contents).
The outer receptacle has a multi-caisson-shaped double structure composed of frames, inner plates, and outer plates. The voids between the inner plates and the outer plates are filled with a heat insulating material to provide heat resistance. Aluminum honeycomb elements are attached to the inner surfaces of the outer receptacle and the lid of the outer receptacle to attenuate any shock against the inner receptacle.
The body of the inner receptacle as well as the lid of the inner receptacle has a single-caisson-shaped structure composed of thick stainless steel plates. An O-ring is provided for sealing on the flange on the interface between the body and lid of the inner receptacle.
The characteristics of the packaging are not altered significantly under normal and accident conditions of transport. The packaging is liable only to small alterations in shape under normal conditions of transport, and such alterations are included among those that are expected to occur under accident conditions of transport.
The packaging suffers no alterations in shape under accident conditions of transport during the thermal test or water immersion test. However, the packaging suffers several alterations in shape during drop tests:
- Impact load during the drop tests causes deformations on the outer plates of the outer receptacle. These deformations are observed as dimensional reductions of the outer receptacle: up to 22 mm in height, up to 6 mm in the horizontal axis normal to the narrower side of the receptacle, and up to 4 mm along the horizontal axis normal to the wider side of the receptacle;
- The space between the inner and outer plates of the outer receptacle is practically maintained;
- The drop impact load onto the inner receptacle is absorbed by deformation of some of the elements on the internal side of the outer receptacle (e.g., aluminum honeycomb elements), resulting in a reduction in distance between the surface of the outer plate of the outer receptacle and the internal surface of the honeycomb elements: from the initial distance of 174.8 mm in routine conditions of transport to 129 mm on the narrower side of the packaging and 136 mm on the wider side; since the inner receptacle is surrounded by honeycomb elements, the drop impact increases the clearance for the inner receptacle.
- The drop impact causes the contents to strike against the inner receptacle, resulting in a slight expansion of the inner receptacle;
- The rod bolts ensuring tight contact of the lid with the body of the inner receptacle are not fractured, thus maintaining the fuel zone in the interior of the inner receptacle; the temperature of the O-ring on the flange II - E - 2
does not exceed its maximum service temperature even under thermal test conditions;
- The boronic stainless steel plates applied to the internal lateral surfaces of the inner receptacle are not damaged, deformed or displaced;
- The boronic stainless steel plates provided like a partition between the two pellet storage box assemblies suffer only small damage and deformation, but the fixing blocks are fractured. This means that the boronic stainless steel plates maintain their relative position between the two pellet storage box assemblies but can move in the space of the inner receptacle.
E.2.3. Neutron absorbers As neutron absorbers, 3 mm thick boronic (concentration: 1 weight percent) stainless steel plates are fixed with an inorganic adhesive in parallel to each of the four internal narrower lateral sides and on each of the two wider internal lateral sides (six absorbers in total) at locations which correspond to the pellet storage box assemblies. Neutron absorbers are also provided like a partition between two pellet storage box assemblies.
It consists of two joined 3 mm thick boronic stainless steel plates.
All these neutron absorbers suffer no alterations in shape or characteristics under normal and accident conditions of transport. Possible displacement of some of the neutron absorbers is described in section E.2.2.
E.3. Characteristics of Analytical Model E.3.1. Analytical Model No limitation is specified for the number of packages to be transported simultaneously. The evaluation of arrayed system covers the evaluations of isolated system, since the evaluation of array system takes water instrusion into account in the evaluation of isolated system. Therefore, the evaluation of isolated systems will not be conducted and the evaluation of arrayed system will be representive. The model adopted for the criticality analysis is a model acting as an array system of unlimited numbers of packages which present specular reflection at their external boundary.
Figs II-E-1 and II-E-2 show the geometrical models of the package under normal conditions of transport and the package under accident test condutions of transport.
Changes in the shape of the package under normal conditions of transport are minor and can be considered as undamaged for analytical model. Therefore, the shape and dimensions of the type GP-01 package were used without modification or adjustment to model the package under normal conditions of transport.
Components such as frames, flanges, bolts, honeycomb elements and spacers which have a small shape are disregarded. In addition, the analytical model is all the more conservative because the effect of the neutron absorbers is not taken into account. The legs of the outer receptacle are also disregarded in dimensions and properties.
The analytical model is conceived in the condition that the contents can move in the clearance in the inner receptacle that is increased by impact shock. However, since possible movement of the contents is expected to have little effect on the results of criticality analysis, the model includes the contents in the center of the inner II - E - 3
receptacle (see Fig. II-E-1).
The model of package under accident conditions of transport are shown below:
- The analytical model is a rectangular parallelepiped whose height dimension is uniformly reduced by 25 mm while the real outer receptacle is reduced by up to 22 mm in the height dimension. The reduction in external dimensions are systematic in the analytical model: 10 mm (uniform) instead of 6 mm (max.) along the horizontal axis normal to the narrower side of the receptacle and 8 mm (uniform) instead of 4 mm (max.)
along the horizontal axis normal to the wider side of the receptacle. The modeling of the system of packages is justified because the reductions in external dimensions increase nuclear interactions of packages and lead to more conservative evaluations;
- The analytical model assumes intentionally large reductions in distance between the surface of the outer plate of the outer receptacle and the internal surface of the honeycomb elements: the original distance of 174.8 mm in routine conditions of transport is reduced to 120 mm instead of 129 mm on the narrower side of the packaging, and to 127 mm instead of 136 mm on the wider side. Along the height axis of the package, the analytical model assumes 0 mm for the lower honeycomb elements: 105 mm is the distance from the surface of the outer plate of the outer receptacle to the inner surface of the honeycomb elements, account taken of maximum deformation of the honeycomb elements. Taking into account deformations in portions thinner than the upper portions around the lid contributes to increasing the effect of nuclear interactions between packages as far as possible, thus enhancing the conservatism. Thus, the clearance in the inner receptacle for the package under accident conditions of transport is larger than for one under normal conditions of transport, increasing possible movement of the contents in the clearance in the inner receptacle (see Fig.
II-E-2). It should be noted, however, that movement of the contents in the clearance will have little effect on the results of criticality analysis;
- Accidental displacements of the inner receptacle and partitions (neutron absorbers) inside the honeycomb elements are taken into account in such a way that the resulting locations of the components will raise the multiplication factor as far as possible;
- Slight expansion of the inner receptacle due to collision of the contents against its inner surfaces is disregarded in the model because such changes will have no effect on the position of the partition (neutron absorber);
- As in the case of package under normal conditions of transport, the frames, flanges, bolts, honeycomb elements and spacers which have a small shape are disregarded and no account is taken of the neutron absorption in the model. Thus, the simplified model (rectangular parallelepiped) conservatively simulates the GP-01 packaging in terms of shape, dimensions, and location of the contents;
- The dimensions and material characteristics of the legs of the outer receptacle are neglected to create a model in which nuclear interactions between packages in an array system are intensified.
II - E - 4
In both the package under normal conditions of transport and the one under accident conditions of transport, an optimal state of moderation is adopted for the nuclear fuel material contained in the package to achieve highest multiplication factors and intensify nuclear interactions between packages to the utmost extent (by disregarding the neutron absorption by the insulator provided in the gaps between inner and outer plates of the outer receptacle). These modeling features are expected to provide a conservative evaluation that covers evaluation of an isolated system.
Fig. II-E-3 shows a geometrical model for the contents (pellet storage box assemblies) of the package.
This model simulates two pellet storage box assemblies. A pellet storage box assembly consists of full-stage pellet storage boxes stacked alternately with partitions which contain a maximum quantity of UO2 pellets and is covered with an assembly cover.
The conservatism of the analytical model is ensured by the relative locations in the assembly of the pellet storage boxes and the pellets contained in these boxes:
- The pellet storage boxes are retained inside the range of positioning blocks and the UO2 pellets remain in the pellet storage boxes. Accordingly, the zone of presence of UO2 pellets is delimited within a rectangle 270 mm x 330 mm inside the positioning blocks. The materials of the pellet storage boxes and other components (such as corrugated plates) are disregarded. Thus, the model is conservative in respect of neutron absorbing effect;
- UO2 pellets are neatly arranged on the corrugated plates in the storage boxes. The pellets are of cylindrical shape to be placed in horizontal orientation. The length of each pellet cylinder is 270 mm, which is the distance of the spacing between positioning blocks provided along the axis of pellet arrangement;
- The analytical model assumes UO2 pellets of any fuel types. The dimensions of the pellet for the package under normal conditions of transport are included in the diameter range 8 mm to 10 mm. The pellet diameter for the package under accident conditions of transport is fixed in the range 0 mm to 10 mm, assuming a state of sludge in the evaluation conservatism which takes into account possible fracture of the pellets. The characteristics of the pellet include enrichment of 5 weight percent (upper limit) and a theoretical density of 10.96g/cm3;
- The number of arrays of fuel pellets in the storage box is varied (increased and decreased) to survey the change in pellet diameter while maintaining the maximum UO2 loading in the pellet storage box(see appendix 1 to chapter II -E);
- An optimal pellet pitch (interaxial distance) is surveyed to maximize the multiplication factor for each of the fuel arrays in the pellet storage boxes(see appendix 1 to chapter II -E);
- The intervals between pellets are assumed to be filled with water. Calculation is conducted to ascertain how reducing the amount of water will lower the multiplication factor(see appendix 1 to chapter II -E).
II - E - 5
Horizontal Section Model Unit: mm 100 75.5 8 0.5 3
5 2.5 Pellet Pellet Storage Storage 422 Box 442 Box 459 820 Assembly Assembly 2 3 2.5 5
5 1 362 1 5 3 6 76 100 3
3 3 8
772 1134 Boronic stainless steel Stainless steel inner plate Stainless steel inner plate Stainless steel outer plate All uncolored voids are in vacuum state.
Fig. II-E-1: Geometrical Model for the package under normal conditions of transport (1/2)
II - E - 6
Vertical Section Model Unit: mm 3
125 2
68 10 3
25 19 100 75.5 8 7.5 422 920 501 Pellet Storage Box Assembly 10 6
46 100 820 Boronic stainless steel Stainless steel inner plate Stainless steel outer plate Stainless steel inner plate All uncolored voids are in vacuum state.
Fig. II-E-1: Geometrical Model for the package under normal conditions of transport (2/2)
II - E - 7
Horizontal Section Model Unit: mm 100 113 120 Pellet Pellet 804 Storage Storage Box Box 422 Assembly Assembly 362 362 117 15 2 100 22 3
127 1114 Vertical Section Model Unit: mm 3
125 2
89 10 3
25 100 895 8 29 422 15 113 127 501 Pellet Storage Box Assembly 6
100 804 Fig. II-E-2: Geometrical Model for the package under accident conditions of transport II - E - 8
Horizontal Section Model Unit: mm Stainless steel assembly cover Vacuum in pellet storage box Boronic stainless steel intermediate partition 422 418 414 330 Water in pellet storage box UO2 pellet Surveyed optimal diameter and number of fuel rod arrays 270 for maximum multiplication factor (one example) 354 358 362 Vertical Section Model 2 Unit: mm 5
3 Uppermost partition UO2 pellet 38 Assembly cover 501 499 Stack of 12 pellet storage boxes and 11 intermediate partitions Intermediate partition Water in pellet storage box Vacuum outside pellet storage box 5 Lowermost partition 422 Fig. II-E-3: Geometrical Model for Pellet Storage Box Assembly II - E - 9
E.3.2. Atom Density in Zones of Analytical Model Table II-E-1 shows the atom densities in various zones of the package adopted for the criticality analysis.
For the UO2 pellets, an enrichment value of 5 weight percent (upper limit) and a theoretical density of 10.96g/cm3 were used. The highest density, 1 g/cm3, at ambient temperature was adopted for the water. A conservative density of 7.9 g/cm3 was specified for stainless steel on the basis of the value (7.93 g/cm3) specified for SUS 304 in the JIS G 4305 standard. For the composition of materials, the appropriate standard composition libraries available on the SCALE Code System were used. While the additive rate for boron in the real boronic stainless steel is 1 weight percent, our analysis adopted 0.75 weight percent for boron and 99.25 weight percent for stainless steel. A density of 7.8 g/cm3 was assumed for the stainless steel.
Table II-E-1: Atom Densities of Materials Used for Calculations Component Material Nuclide Atom Density (atoms/barncm)
UO2 pellet 235 U 1.24E-03 (enrichment of 235 U: 5 238 U 2.32E-02 weight %; density of UO2 pellet: H 10.96 g/cm3) O 4.89E-02 Water H 6.69E-02 (density: 1 g/cm3) O 3.34E-02 C 3.17E-04 Si 1.69E-03 P 6.91E-05 Stainless steel Cr 1.74E-02 (density: 7.9 g/cm3)
Mn 1.73E-03 Fe 5.82E-02 Ni 7.70E-03 C 3.11E-04 Si 1.66E-03 P 6.77E-05 Boronic stainless steel Cr 1.70E-02 (ratio of added boron: 0.75 Mn 1.70E-03 weight percent; density: 7.8 Fe 5.71E-02 g/cm3)
Ni 7.55E-03 10B 6.48E-04 11B 2.61E-03 II - E - 10
E.4. Subcriticality Evaluation E.4.1. Calculation Conditions The type GP-01 packaging is designed to contain pellets of uranium oxides or pellets of uranium oxides mixed with gadolinium, enriched to 5 weight percent. To model the pellets, we disregarded gadolinium, neutron absorber, and considered them to be composed of uranium oxides. To maximize the multiplication factor of the fuel, upper limits were adopted: 5 weight percent for the enrichment and 10.96g/cm3 for the pellet density.
The only components considered in modeling the contents were the assembly cover and neutron absorbing partition. The partition is composed of boronic stainless steel plates whose additive rate for boron is 1 weight percent. To model the contents, 0.75 weight percent was adopted for the rate to increase the degree of conservatism. Many other components of the contents which contribute to neutron absorption were disregarded to maintain or increase the degree of conservatism: pellet storage boxes (body and lid), corrugated plates for arrangement of pellets, positioning blocks on partition, pillars and nuts for assembly, and assembly cover handles.
The analytical model for the packageconsists of the inner and outer plates of the outer receptacle (body and lid), the stainless steel plates of the inner receptacle and the boronic stainless steel plates applied to the inner surfaces of the inner receptacle. Here again, the real boronic stainless steel has an additive rate for boron of 1 weight percent, but the modeling was based on 0.75 weight percent to increase the degree of conservatism.
Similarly to the contents, many other components which contribute to neutron absorption were disregarded for the modeling: frames, legs, insulator, flanges, aluminum honeycomb elements, protective rectangular pipes, and anti-vibration rubber.
This modeling scheme thus allows us to evaluate the multiplication factor for the package conservatively.
E.4.2. Entry of water into the package The criticality analysis assumed entry of water into the package regardless of occurrence of damage to the package. No water is supposed to be present in or on the components which were taken into account for the modeling: stainless steel plates, boronic stainless steel plates and pellets (refer to E.4.1). No water is supposed to be present in the space occupied by pellets either except in the voids outside the pellet storage boxes. The last consideration is for providing an optimal state of moderation. The water content ratio (in percent) in these voids will be varied to check possible effects of the variation on the resulting state of moderation as shown in appendix 1 to chapter II-E. The voids outside the pellet storage boxes are assumed to be in a vacuum state to maximize nuclear interactions between packages in an array system and achieve a higher degree of conservatism. In parallel, the analysis will also concern the case in which water enters the voids outside the pellet boxes: voids between the inner and outer plate of the outer receptacle as well as in the void surrounding the inner receptacle inside the inner plates of the outer receptacle.
E.4.3. Method The criticality analysis resorted to the KENO V.a code. This code is a multi-group Monte Carlo code developed by researchers from Oak Ridge National Laboratory, USA, which has the capability of handling complicated three-dimensional geometrical shapes in a precise manner. It is a criticality calculation method for II - E - 11
calculating neutron multiplication factors.
The criticality analysis used 44-group cross sections based on ENDF-B/V as master library.
E.4.4. Results of Evaluation Table II-E-2 shows the results of calculation for the infinite array system of the packages under normal conditions of transport and accident conditions of transport described in sections E.4.1 through E.4.3.
Table II-E-2: Calculation of Neutron Multiplication Factors System to be evaluated Pellet storage box assembly Pellet storage box assembly A B Infinite array system of the 0.918 0.878 packages under normal 0.920 0.880 conditions of transport Infinite array system of the 0.925 0.879 packages under accident 0.928 0.882 conditions of transport Note: The figures in the upper lines of the cells are center values for Monte Carlo calculation. (The figures is rounded off to three decimal places)
Those in the lower lines are evaluation values (=center value + 3 times statistic standard deviation value). (The figures is rounded up to three decimal places)
II - E - 12
E.5. Benchmark Test The International Criticality Safety Benchmark Evaluation Project (ICSBEP), with the official acknowledgment of OECD/NEA, has issued the International Handbook of Evaluated Criticality Safety Benchmark Experiments.
The ICSBEP Handbook presents criticality safety benchmark specifications developed from nuclear critical facilities of many countries, classified by parameter group. We extracted 340 cases of benchmark tests from the category LEU-COM-THERM (low-enriched uranium/compound/thermal neutron spectrum). For theses cases, experiment analyses were carried out by the calculation method used for criticality evaluation of the GP-01 package. Fig. II-E-4 shows the results. Table II-E-3 shows the results of statistic processing of the experiment analysis results for the 340 cases shown in Fig. II-E-4.
Table II-E-3 shows that the calculation method used for the criticality evaluation of the GP-01 package is capable of evaluating neutron multiplication factors with satisfactory accuracy.
1.025 1.020 1.015 1.010 Neutron Multiplication Factor 1.005 1.000 0.995 0.990 0.985 0.980 0.975 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 Pellet Diameter (cm)
Fig. II-E-4: Results of Benchmark Experiment Analysis II - E - 13
Table II-E-3: Results of Benchmark Experiment Analysis Number of Cases 340 Average error (k: average for 1 - k) 0.0046 Standard deviation () 0.0080 Confidence coefficient (f: 97.5% 2.154 confidence/97.5% probability)
Estimated criticality lower limit multiplication 0.978 factor (1- k- f)
Restriction value 0.95 II - E - 14
E.6. Summary of Results and Evaluation The GP-01 package was subjected to a criticality analysis. For the purpose of the analysis, various configurations were adopted in the modeling. The highest value determined for the neutron multiplication factor is 0.928, account taken of the statistic standard deviation. This value is lower than 0.95 and implies no problem in terms of criticality safety.
References
- SCALE: A Modular Code System for Performing Standardized Computer Analyses for Licensing Evaluations, ORNL/TM-2005/39, Version 5, Vols. I-III, April 2005. Available from Radiation Safety Information Computational Center at Oak Ridge National Laboratory as CCC-725.
- International Criticality Safety Benchmark Evaluation Project (ICSBEP) Working Group, http://www.nea.fr/html/science/wpncs/icsbep/welcome.html.
- International Handbook of Evaluated Criticality Safety Benchmark Experiments, NEA/NSC/DOC(95)03.
II - E - 15
Appendix 1 to Chapter II-E Results of Survey Calculation
- 1. Pellet Diameter and Neutron Multiplication Factor The GP-01 packaging is designed to contain UO2 pellets of any type of fuel. Therefore, ranges of pellet diameters are specified: 8 mm to 10 mm for the package under normal conditions of transport and 0 mm to 10 mm for the package under accident conditions of transport since a sluge-like condition is assumed as a conservative evaluation condition considering the crushing of UO2. Accordingly, survey calculations were conducted while increasing and decreasing the number of pellet arrays per storage box and adopting the maximum UO2 loading per storage box to vary the pellet diameter. Note that the corrugated plates inside the pellet storage box were not modeled. Figs. II-E.App-1 and II-E.App-2 show the results of calculation for the package under normal conditions of transport and the package under accident conditions of transport, respectively. Fig. II-E.App-3 shows a diagram depicting the results of calculation shown in Fig. II-E.App-2 but enlarged to become comparable with the results shown in Fig. II-E.App-1 in the same pellet diameter range.
The highest values in Figs. II-E.App-1 and II-E.App-2 are transcribed in Table II-E-2. A comparison of the data in Fig. II-E.App-1 with those in Fig. II-E.App-3 reveals that the package under accident test conditions of transport presents only slightly higher multiplication factors than the package under normal conditions of transport. The difference in evaluation value between the two systems can be mainly attributed to the difference in pellet diameter range.
Fig. II-E.App-1: Survey Results: Pellet Diameter in the package under normal conditions of transport II - E.App1 - 1
0.93 0.92 Multiplication Factor (k+3) 0.91 2 stages in box 3 stages in box 4 stages in box 5 stages in box 0.90 6 stages in box 8 stages in box 10 stages in box 0.89 12 stages in box 16 stages in box 24 stages in box 32 stages in box 0.88 40 stages in box Homogenized model Envelope curve 0.87 0 0.2 0.4 0.6 0.8 1 Pellet Diameter (cm)
Fig. II-E.App-2: Survey Results: Pellet Diameter in the package under accident conditions of transport 0.93 2 Stages in box 3 Stages in box 4 Stages in box 0.92 Multiplication Factor (k+3) 0.91 0.90 0.89 0.88 0.8 0.82 0.84 0.86 0.88 0.9 0.92 0.94 0.96 0.98 1 Pellet Diameter (cm)
Fig. II-E.App-3: Survey Results: Pellet Diameter in the package under accident conditions of transport (detail)
II - E.App1 - 2
- 2. Effect of Variation of Pellet Pitch on Multiplication Factor The evaluations shown in Figs. II-E.App-1 to II-E.App-3 were based on the maximum pellet pitch along the height axis of the package. This measure was taken to avoid reducing the degree of conservatism by reducing the pellet pitch along the height axis of the package in the 38 mm high storage box. Reducing the pellet pitch along this axis would result in expelling the appropriate portions of water between pellets, thus simply reducing the multiplication factor. Fig. II-E.App-4 shows the results of calculation of multiplication factors for different pellet pitches along the height axis.
0.93 0.92 Multiplication Factor (k+3) 0.91 0.90 0.89 0.67 0.68 0.69 0.7 0.71 0.72 0.73 0.74 0.75 0.76 0.77 Vertical Pellet Pitch ( cm)
Fig. II-E.App-4: Multiplication Factor vs. Pellet Pitch along Package Height Axis In the horizontal plane, the pellet storage box occupies a space delimited by a rectangle 270 mm x 330 mm. If the maximum pellet pitch was adopted, excessive moderation would occur and result in attaining a peak of multiplication factor in response to change in pellet pitch. Therefore, the evaluations shown in Figs.
II-E.App-1 to II-E.App-3 were carried out to determine the peaks of multiplication factor by varying the horizontal pellet pitch. Fig. II-E.App-5 shows the results of these evaluations based on variable horizontal pellet pitch in different pellet arrays for four-stack configurations along the height axis of the package.
Thus, the survey of pellet diameter ranges was carried out while varying the number of pellet arrays and the pellet pitch in various configurations to maximize the multiplication factor. Our evaluation of multiplication factors was conservative since it did not depend on the state of pellets contained in the storage boxes.
II - E.App1 - 3
0.93 0.92 Multiplication Factor (k+3) 0.91 4 Stages x 14 Arrays 4 Stages x 16 Arrays 4 Stages x 19 Arrays 0.90 4 Stages x 24 Arrays 4 Stages x 28 Arrays 4 Stages x 33 Arrays 4 Stages x 39 Arrays 0.89 4 Stages x 58 Arrays 4 Stages x 92 Arrays 0.88 0.87 0 0.5 1 1.5 2 2.5 Horizontal Pellet Pitch (cm)
Fig. II-E.App-5: Multiplication Factor vs. Horizontal Pellet Pitch
- 3. Effect of Water Content Ratio in Pellet Zone (in Storage Box) on Multiplication Factor Entry of water was taken into account to ensure optimal moderation within the perimeter of pellets. Fig.
II-E.App-6 shows the results of calculation of multiplication factors for various water content ratios.
The curve shown in Fig. II-E.App-6 clearly indicates that the multiplication factor simply increases when the water content ratio is raised.
0.95 0.90 0.85 Multiplication Factor (k+3) 0.80 0.75 0.70 0.65 0.60 0.55 0 10 20 30 40 50 60 70 80 90 100 Water Content Ratio (%)
Fig. II-E.App-6: Multiplication Factor vs. Water Content in Pellet Zone within Storage Box II - E.App1 - 4
- 4. Effect of Water Content outside Pellet Zone (outside Storage Box) on Multiplication Factor In the analysis of arrayed system, the voids outside the pellet zone were regarded as being in vacuum state.
This is make to model of the array system with the largest nuclear interactions from the results shown below.
Figs. II-E.App-7 and II-E.App-8 show the results of calculation of multiplication factors for variable water content ratios in different zones, account taken of entry of water into the voids between the inner and outer plates of the outer receptacle and the void surrounding the inner receptacle inside the inner plates of the outer receptacle, respectively. These figures suggest that the evaluation conditions including vacuum voids outside the pellet storage boxes are conservative.
0.95 0.90 Multiplication Factor (k+3) 0.85 0.80 0.75 0.70 0 10 20 30 40 50 60 70 80 90 100 Water Content Ratio (%)
Fig. II-E.App-7: Multiplication Factor vs. Water Content between Inner and Outer Plates of Outer Receptacle II - E.App1 - 5
0.95 Multiplication Factor (k+3) 0.90 0.85 0.80 0.75 0 10 20 30 40 50 60 70 80 90 100 Water Content Ratio (%)
Fig. II-E.App-8: Multiplication Factor vs. Water Content between Inner and Outer Plates of Outer Receptacle and Inner Receptacle II - E.App1 - 6
(II)-F Aging Considerations for Nuclear Fuel Packages F.1 Aging Factors to be considered This chapter considers the conditions of use expected for the package during the period in which it is planned to be used and aging with that.
The planned period of use for this packaging is 80 years, and the total number of transports is 160 times during the period of use, with each transport usually lasting up to 4 months. The number of times this packaging is scheduled to be lifted is 10 times per transport and 20 times per year other than transport, for a total of 3,200 times (160x10 + 80x20) throughout the period of use.
Possible aging factors during the period of use of this package include temperature changes (heat) during receptacle storage and use, radiation generated from contents, chemical changes such as corrosion, and fatigue caused by repetitive stress. Therefore, the factors that cause these aging changes with respect to the components of this packaging and the contents that are used repeatedly are evaluated.
In the evaluation of heat, radiation, and chemical changes, 80 years of continuous use is considered as a more conservative condition than planned use. In the evaluation of fatigue, as a more conservative condition than the planned use, the number of transports over the period of use is assumed to be twice as many as planned (160x2 = 320 times) and the number of times lifted per year other than transport is assumed to be twice as many as planned (20x2 = 40 times), and stress considered to occur a total of 6,400 times (320x10 + 80x40). Furthermore, stress due to internal pressure is considered to occur 29,200 times (80x365 = 29,200 times), assuming transport once a day for 80 years as a more conservative condition than the planned use.
II - F -1
F.2 Evaluation of the need to consider aging in safety analysis The components of this packaging for which aging is considered are listed below, with those being components supporting safety functions and the materials used in them.
Packaging component Material Packaging structural material Stainless steel Rod bolt Chrome molybdenum steel Shock absorbing material Aluminum alloy (aluminum honeycomb)
Neutron absorber Borated Stainless Steel Insulation material Ceramic fiber O-rings are replaced with new ones before transport, so aging is not considered.
Next, the following is a list of contents that are used repeatedly, and the materials used in them as contents aging is considered for.
Contents Material Pellet storage box Stainless steel Pellet storage box assembly structural material Intermediate partition plate (neutron Borated Stainless Steel absorber)
In summary, aging should be considered for the following five materials in packagings and contents.
- Stainless steel
- Chrome molybdenum steel
- Aluminum alloy
- Borated stainless steel
- Ceramic fiber The following are aging considerations for each material in terms of heat, radiation, chemical changes, and fatigue.
II - F -2
(1) Stainless steel The aging considerations for stainless steel are shown in (II)-F Table 1.
(II)-F Table 1. Aging Considerations for Stainless Steel [1/2]
Material Aging factor Evaluation of aging Presence of aging Stainless Heat The temperature range of stainless steel expected during the Not steel period of use, which is -40°C to 114°C (see (II)-B.4.6), is present considered. The temperature at which the material is affected by creep is 433°C, one-third of the melting point of stainless steel (1300°C or higher), which is sufficiently high compared with the highest temperature (114°C) expected during transport. So, even if stainless steel were continuously placed under the above temperature environment during its period of use, it would not be affected by aging such as structural changes, creep, and cracking. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Radiation The condition set forth is the maximum storage volume Not (264 kg) of uranium dioxide with an enrichment of 5% in the present inner receptacle over an 80-year period of use. The cumulative neutron irradiation over the period of use is less than 6x1011 n/cm2, which is sufficiently small compared with the neutron irradiation of 1016 n/cm2 said to affect the material strength of stainless steel, so the material is not affected by aging due to irradiation1). Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Chemicals Corrosion is unlikely to occur with stainless steel because a Not passive film is formed on the surface of the material. present Moreover, if corrosion is found on the outer surface of the packaging during visual inspection in periodic voluntary inspection, it shall be repaired, and if corrosion is found on the pellet storage box assembly and the pellet storage box, it shall be repaired or replaced. Furthermore, pre-shipment inspections confirm that there are no visible abnormalities in the external surface of the packaging, pellet storage box assembly, and pellet storage box. Therefore, the material is not affected by corrosion or other aging during the period of use.
Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -3
(II)-F Table 1. Aging Considerations for Stainless Steel [2/2]
Material Aging factor Evaluation of aging Presence of aging Stainless Fatigue Since two factors, lifting and difference in internal and Not present steel external pressure, cause repetitive stress in the structural materials of packagings, it is necessary to consider aging.
In considering the evaluation of stress generated by lifting at the B section of the lifting attachment of the outer receptacle where stress was greatest, the stress amplitude generated at the B section of the outer receptacle lifting attachment was 57.5 MPa (see (II)-A.4.4.10 Evaluation of Repetitive Stress due to Lifting). According to the fatigue curve of stainless steel shown in (II)-F Figure 1, fatigue failure does not occur even if the stress amplitude is 100 N/mm2 or less and repetitive stress is generated more than 107 times in an environment from room temperature to 700°C. Even considering the stress generated by lifting 6,400 times in total, the stress is sufficiently small compared with the allowable number of repetitions.
Among the stresses generated by the difference in internal and external pressure, the greatest stress occurred on the inner wall (bottom) of the inner receptacle when the temperature of the inner receptacle reached 59°C after the contents were packed at 0°C during normal transport and the ambient pressure dropped to 60 kPa in absolute pressure, and the stress amplitude was 84.5 MPa (see (II)-A.4.6.3 Evaluation of Repetitive Stress due to Internal Pressure).
According to the fatigue curve of stainless steel shown in (II)-F Figure 1, fatigue failure does not occur even if the stress amplitude is 100 N/mm2 or less and repetitive stress is generated more than 107 times in an environment from room temperature to 700°C. Even considering the stress generated 29,200 times in total, the stress is sufficiently small compared with the allowable number of repetitions.
In addition, pellet storage box and pellet storage box assembly are not subject to stress caused by difference in internal and external pressure or handling.
Therefore, aging due to fatigue does not occur. Thus, there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -4
(II)-F Figure 1. Stainless Steel Fatigue Curve (Source) Handbook for stainless steels - 3rd Edition - Japan Stainless Steel Association (January 1995)
II - F -5
(2) Chrome molybdenum steel The aging considerations for chrome molybdenum steel are shown in (II)-F Table 2.
(II)-F Table 2. Aging Considerations for Chrome Molybdenum Steel [1/2]
Material Aging Evaluation of aging Presence of factor aging Chrome Heat The temperature range of chrome molybdenum steel Not present molybdenum expected during the period of use, which is -40°C to 114°C steel (see (II)-B.4.6), is considered. The temperature at which the material is affected by creep is 300°C, one-third of the melting point of chrome molybdenum steel (900°C or higher), which is sufficiently high compared with the highest temperature (114°C) expected during transport. So, even if chrome molybdenum steel were continuously placed under the above temperature environment during its period of use, it would not be affected by aging such as structural changes, creep and cracking in the temperature range expected during the period of use. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Radiation The condition set forth is the maximum storage volume Not present (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle over an 80-year period of use. The cumulative neutron irradiation over the period of use is less than 6x1011 n/cm2, which is sufficiently small compared with the neutron irradiation of 1018 n/cm2 said to affect the material strength of chrome molybdenum steel, so the material is not affected by aging due to irradiation2). Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Chemicals Chrome molybdenum steel is resistant to corrosion because it Not present is nickel-chromium plated as an anti-corrosion treatment. In addition, if corrosion is found on rod bolts during visual inspection in periodic voluntary inspection, it shall be repaired or replaced. Furthermore, pre-shipment inspections confirm that there are no visible abnormalities. Therefore, the material is not affected by corrosion or other aging during the period of use. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -6
(II)-F Table 2. Aging Considerations for Chrome Molybdenum Steel [2/2]
Material Aging Evaluation of aging Presence factor of aging Chrome Fatigue Since two factors, lifting and difference in internal and external Not present molybdenum pressure, cause repetitive stress in the rod bolts using chrome steel molybdenum steel, it is necessary to consider aging.
Lifting causes a stress amplitude of up to 92.3 MPa (see (II)-
A.4.4.10 Evaluation of Repetitive Stress due to Lifting) in rod bolts. According to the fatigue curve of molybdenum steel shown in (II)-F Figure 2, fatigue failure does not occur even if the stress amplitude is 206 MPa (3.0x104 psi) or less and repetitive stress is generated more than 106 times in an environment from room temperature to 371°C (700°F). Even considering the stress generated by lifting 6,400 times in total, the stress is sufficiently small compared with the allowable number of repetitions.
Among the stresses generated by difference in internal and external pressure, the greatest stress occurred when the temperature of the inner receptacle reached 59°C after the contents were packed at 0°C during normal transport and the ambient pressure dropped to 60 kPa in absolute pressure, and stress amplitude of 92.1 MPa is generated on the rod bolt (see (II)-A.4.6.3 Evaluation of Repetitive Stress due to Internal Pressure). According to the fatigue curve of molybdenum steel shown in (II)-F Figure 2, fatigue failure does not occur even if the stress amplitude is 206 MPa (3.0x104 psi) or less and repetitive stress is generated more than 106 times in an environment from room temperature to 371°C (700°F). Even considering the stress generated 29,200 times in total, the stress is sufficiently small compared with the allowable number of repetitions.
Therefore, aging due to fatigue does not occur. Thus, there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -7
(II)-F Figure 2. Chrome Molybdenum Steel Fatigue Curve (Source) Tatsuo Oku, Toshihiko Kikuyama, Kiyoshi Fukaya, Tsuneo Kodaira, Mechanical Properties Data of 2-1/4 Cr-Mo Steel for the Experimental Very High Temperature Gas-Cooled Reactor (November 1978)
II - F -8
(3) Aluminum alloy The aging considerations for aluminum alloy are shown in (II)-F Table 3.
(II)-F Table 3. Aging Considerations for Aluminum Alloy Material Aging Evaluation of aging considerations Presence of factor aging Aluminum Heat The temperature range of aluminum alloy expected during the Not present alloy period of use, which is -40°C to 114°C (see (II)-B.4.6) is considered. The temperature range expected in the period of use is sufficiently low compared with the temperature at which the strength of aluminum alloy decreases (150°C or higher). In addition, since aluminum alloy is used in the interior of packagings, there is no contact with outside air or moisture, which can accelerate aging due to heat. Therefore, the material is not affected by aging due to heat. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Radiation The condition set forth is the maximum storage volume (264 kg) Not present of uranium dioxide with an enrichment of 5% in the inner receptacle over an 80-year period of use.
The cumulative neutron irradiation over the period of use is less than 6x1011 n/cm2, which is sufficiently small compared with the neutron irradiation of 1021 n/cm2 said to affect the material strength of aluminum alloy3). Therefore, the material is not affected by aging due to irradiation. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Chemicals Corrosion is unlikely to occur with aluminum alloy because an Not present oxide film is formed on the surface of the material. In addition, aluminum alloy is used in the interior of packagings and is not directly exposed to sunlight or rain during transport, so it is not affected by corrosion or other aging. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Fatigue Since stress resulting from difference in internal and external Not present pressure and handling does not occur at the points where aluminum alloy is used, aging due to fatigue does not occur.
Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -9
(4) Borated Stainless Steel The aging considerations for Borated Stainless Steel are shown in (II)-F Table 4.
(II)-F Table 4. Aging Considerations for Borated Stainless Steel Material Aging Evaluation of aging Presence factor of aging Borated Heat The temperature range of borated stainless steel expected during Not present Stainless the period of use, which is -40°C to 114°C (see (II)-B.4.6), is Steel considered. Borated stainless steel is composed of 99% stainless steel and 1% boron, so its basic properties do not differ from those of stainless steel. Therefore, as with stainless steel, borated stainless steel is not affected by aging such as structural changes, creep and cracking in the temperature range expected during the period of use. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Radiation The condition set forth is the maximum storage volume (264 kg) Not present of uranium dioxide with an enrichment of 5% in the inner receptacle over an 80-year period of use.
Borated stainless steel is composed of 99% stainless steel and 1%
boron, so its properties with respect to neutron irradiation do not differ from those of stainless steel. The cumulative neutron irradiation over the period of use is less than 6x1011 n/cm2, which is sufficiently small compared with the neutron irradiation of 1016 n/cm2 said to affect the material strength of stainless steel1).
In addition, the 10B impairment rate from cumulative neutron irradiation is less than 8x10-10, and neutron absorption performance is not affected, so the material is not affected by aging due to irradiation. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Chemicals Corrosion is unlikely to occur with borated stainless steel because a Not present passive film is formed on the surface of the material like with stainless steel. Furthermore, borated stainless steel is used for partitions between the sides of the inner receptacle and the pellet storage box assembly, and for the pellet storage box assembly, and those are not directly exposed to sunlight or rain during transport, so it is not affected by corrosion or other aging. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Fatigue Since stress resulting from internal/external pressure differences Not present and handling does not occur at the points where borated stainless steel is used, aging due to fatigue does not occur. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -10
(5) Ceramic fiber Ceramic fiber is an inorganic fiber composed mainly of alumina (AlO2) and silica (SiO2). The aging considerations for ceramic fiber are shown in (II)-F Table 5.
(II)-F Table 5. Aging Considerations for Ceramic Fiber Material Aging Evaluation of aging Presence of factor aging Ceramic Heat The temperature range of ceramic fiber expected during the Not present fiber period of use, which is -40°C to 114°C (see (II)-B.4.6), is considered. The temperature at which crystal precipitation, which causes heating and shrinkage of ceramic fiber, occurs is between 950°C and 1000°C4),
which is sufficiently high compared with the maximum temperature (114°C) expected during transport, so even if ceramic fiber is placed under the above temperature, it is not affected by aging such as structural changes. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Radiation The condition set forth is the maximum storage volume Not present (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle over an 80-year period of use.
The effects of aging are confirmed for main components of ceramic fiber, alumina (AlO2) and silica (SiO2). The cumulative neutron irradiation over the period of use is less than 6x1011 n/cm2, which is sufficiently small compared with the neutron irradiation of 1017 n/cm2 said to affect the material strength of aluminum and silica, so the material is not affected by aging due to irradiation5). Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Chemicals Ceramic fiber is an inorganic fiber and a highly corrosion- Not present resistant material, so corrosion is unlikely to occur. Since it is sealed by stainless steel outer and inner plates of the outer receptacle, it is not in contact with the outside air or moisture and is not affected by corrosion or other aging. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
Fatigue Since stress resulting from difference in internal and external Not present pressure and handling does not occur at the points where ceramic fiber is used, aging due to fatigue does not occur. Thus, there is no need to consider aging, and there is no impact on the conformity of the package to the technical standards set forth in the regulations.
II - F -11
F.3 Details of aging considerations in safety analysis As indicated in the previous section, the need to consider aging was evaluated for the components that provide safety functions related to this package and for the materials of contents that are used repeatedly.
For aluminum alloy, borated stainless steel, or ceramic fiber, it was confirmed that aging during the period of use does not need to be considered; and for stainless steel and chrome molybdenum steel, it was confirmed that aging during the period of use does not need to be considered with aging factors in exposure to heat, radiation, and chemicals.
For the outer receptacle lifting attachments and the inner receptacle made of stainless steel and for rod bolts made of chrome molybdenum steel, it is necessary to consider aging due to fatigue because of repetitive stress caused by lifting and difference in internal and external pressure. Fatigue due to lifting and difference in internal and external pressure was evaluated considering the most severe stress conditions and the conservative number of repetitions assumed during the period of use, and it was confirmed that no aging due to fatigue occurred during the period of use and that there was no impact on conformity of the package to the technical standards set forth in the regulations.
II - F -12
References (1) R. K. Nanstad K. Farrell, D. N. Braski, and W. R. Corwin Accelerated Neutron Embrittlement of Ferritic Steels at Low Fluence: Flux and Spectrum Effects (1988)
(2) Tatsuo Oku, Toshihiko Kikuyama, Kiyoshi Fukaya, Tsuneo Kodaira, Mechanical Properties Data of 2-1/4 Cr-Mo Steel for the Experimental Very High Temperature Gas-Cooled Reactor (November 1978)
(3) David J. Alexander Material for Neutron Sources: Cryogenic and Irradiation Effects (1990)
(4) Mitsuo Yamashita, Mitsuru Wakamatsu Aluminum Oxide Fibers as Insulation Materials for High-temperature Furnaces (1983)
(5) Koji Fukuya, Kunio Ozawa, Michitaka Terasawa, Data Compilation for Radiation Effects on Ceramic Insulators (December 25, 1987)
II - F -13
(II)-G Evaluation of Conformity to Regulations and Stipulations in the Public Notice Statements are given for each article that the package design complies with the technical standards set forth in the regulations and stipulations in the public notice.
Section in Section in Statements Correspondenc Regulations Public Notice e with Section in Application Article 3 Article 4 and In design change, there is no change in the contents, which will be a (I)-A subarticle 1 Appendix condition for judging conformity. (I)-B paragraph 2 Table 1 Therefore, as with existing authorization, the A2 value is unlimited because (I)-D the radioactive material contained in this package is classified as Materials other than special-shape nuclear fuel material.
Thus, there is no change in the fact that said package is classified as type A package in the technical standards.
Article 3 The planned period of use for the packaging is 80 years, and the total (II)-F subarticle 3 number of transports is 160 times during the period of use, with each transport expected to usually last up to 4 months. The impact of the aging that needs to be taken into account upon conformity to technical standards was evaluated for components that provide safety functions related to the package and the materials of contents (stainless steel, chrome molybdenum steel, aluminum alloy, borated stainless steel, or ceramic fiber) that are used repeatedly.
- Under the conditions on the conservative side, which is assumed to be the maximum temperature at which components, etc., are expected to be in use for 80 consecutive years, no structural changes, creep, cracking, or thermal decomposition occur, so there is no need to consider aging and the material is not affected by aging due to heat.
- As a conservative condition, the cumulative irradiation in the case of the maximum storage volume (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle for 80 consecutive years is sufficiently small compared with the dose affecting the main materials, so there is no need to consider aging, and the material is not affected radiation.
- With stainless steel and borated stainless steel, a passive film is formed on the surface of the material, aluminum alloys have an oxide film on the surface, and rod bolts using chrome molybdenum steel are nickel-chromium plated, so they are resistant to corrosion. If corrosion is found on the outer surface of stainless steel packagings in visual inspection in the periodic voluntary inspection, they shall be repaired; and if corrosion is found on rod bolts made of chrome molybdenum steel and on stainless steel contents, they shall be repaired or replaced. Furthermore, pre-shipment inspections confirm that there are no visible abnormalities in the outer surface of the packaging, stainless steel contents, and chrome molybdenum steel rod bolts. Ceramic fiber is an inorganic fiber and corrosion-resistant, and is sealed by stainless steel outer and inner receptacle plates, so there is no contact with the outside air or moisture. In addition, borated stainless steel and aluminum alloy are used in the interior of packagings and are not directly exposed to sunlight or rain, so there no need to consider aging and they are not affected by aging due to chemical changes.
- Repetitive stress occurs in stainless steel used in the structural materials of packaging and chrome molybdenum steel used in rod bolts, so it is necessary to consider aging. For stainless steel and rod bolts, stress from the difference in internal and external pressure and stress from lifting was assumed to occur 29,200 times and 6,400 times, respectively during the period of use as more conservative conditions than planned, and they were compared with the allowable number of repetitions determined from the assumed maximum stress. As a result, the number of repetitions of stress assumed during the period of use is sufficiently small and aging due to fatigue does not occur.
For aluminum alloy, borated stainless steel, and ceramic fiber, stress caused by difference in internal and external pressure or handling does not occur, so there is no need to consider aging and they are not affected by aging due to fatigue.
Thus, there is no impact on conformity to the technical standards set forth in the regulations.
II - G - 1
Section in Section in Statements Correspondenc Regulations Public e with Section Notice in Application Article 4 In design change, there is no change in the packaging material and (I)-C (12) paragraph 1 structure, which will be conditions for judging conformity.
Therefore, as with existing authorization, the gross weight of the package is less than 1,300 kg and it is equipped with lifting attachments on the corners of the lid of the outer receptacle that can be manipulated with hooks of a crane or a chain block to lift the package. It can also be easily and safely transported with transporting devices such as forklift and pallet trucks by supporting between the legs on the bottom of the outer receptacle.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 4 In design change, there is no change in the packaging material and paragraph 2 structure, which will be conditions for judging conformity. Therefore, even considering the temperature and internal pressure changes and vibrations of the packaging expected during transport as shown below, there is no change to conformity of the technical standards.
- Ambient temperature during transport is -40°C to 38°C. The minimum temperature of the packaging is -40°C, the same as the ambient (II)-B.4.2 temperature. Maximum temperature of the outer receptacle is 114°C, (II)-B.4.3 maximum temperature of the inner receptacle is 75°C, and average temperature inside the inner receptacle is 59°C, based on the analysis results from the ANSYS code, taking into account the effect of solar thermal radiation.
- The temperature rise of the package due to the change in ambient (II)-A.5.1.2 temperature expected during transportation is small, and because the structural material is metal and has good thermal conductivity, the temperature difference between each part of the packaging is small and no thermal expansion difference occurs due to the temperature difference. In addition, the main structural materials of the outer receptacle, outer receptacle lid, inner receptacle, and inner receptacle lid, such as the inner and outer plates, frame, and flange, as well as the pellet storage box assembly to be contained in the packaging, are all made of stainless steel, so no thermal expansion differences due to dissimilar materials occur.
- When the temperature at packing is 0°C and the average temperature inside the inner receptacle is 59°C and the ambient pressure drops to 60 kPa in absolute pressure, the maximum internal and external pressure (II)-A.4.6 difference of the inner receptacle is 63 kPa. However, the stress generated (II)-B.4.2 in the inner receptacle itself and in the rod bolts that firmly tighten the body and lid of the inner receptacle is smaller than the standard value, so no cracks, damage, etc., occur in the inner receptacle. The maximum pressure difference between the inside and outside of the inner receptacle due to temperature change from -40°C to 59°C, which is the temperature range of the inner receptacle, is 43 kPa. However, the stress generated in (II)-A.5.1.3 the inner wall (narrow side), inner wall (wide side), inner wall (bottom),
inner wall (top), and rod bolts of the inner receptacle are all smaller than the standard value, so no cracks, damage, etc., occur in the inner receptacle.
- During transport, the package is secured to the vehicle and the integrity of the package is ensured even when the maximum weight of the package and acceleration expected during transport are considered. In addition, the (II)-A.4.7 natural frequency of the package differs from the frequency range of the excitation force received from the vehicle, and even if the effect of response amplitude is taken into account, the structural integrity of the package is ensured and there is no risk of cracking or damage.
II - G - 2
Section in Section in Statements Correspondenc Regulations Public e with Section Notice in Application Article 4 In design change, there is no change in the packaging material and (I)-C (11) paragraph 3 structure, which will be conditions for judging conformity. (I)-C (6)
Therefore, as with existing authorization, the only protruding portions of the package are the legs provided on the external bottom surface of the outer receptacle. However, these legs are useful elements of the package, serving as positioning blocks when two packages of this model are stacked one on top of another. The package can easily be decontaminated since the external surfaces of the package are configured with stainless steel plates.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
II - G - 3
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 4 In design change, there is no change in the packaging material and structure, (II)-A.4.1 paragraph 4 which will be conditions for judging conformity, and the components of the packaging are made of chemically stable materials, so there is no change in the fact that there is no risk of dangerous physical actions or chemical reactions occurring due to contact between the materials.
In design change, there is no change in the contents, which will be a condition for judging conformity. Therefore, as with existing authorization, the pellet (II)-A.5.1.2 storage box assembly to be contained in the packaging is stainless steel, the same structural material as the receptacle, and it will not contact the inner receptacle due to thermal expansion. Therefore, there is no change in the fact that there is no risk of dangerous physical actions occurring.
In design change, there is no change in the contents, which will be a condition for judging conformity. Therefore, as with existing authorization, the pellet (II)-A.4.1 storage box assembly to be contained in the packaging is stainless steel, a chemically stable material, so there is no change in the fact that there is no risk of corrosion or other dangerous chemical reaction occurring with the packaging.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 4 In design change, there is no change in the packaging structure, which will (I)-C (10) paragraph 5 be a condition for judging conformity.
Therefore, as with existing authorization, this package is not equipped with valves or equivalents, so the technical standards set forth in the regulations do not apply.
Article 4 Article 9 In design change, there is no change in the surface density regulatory limit, (III)-A.2 paragraph 8 which will be a condition for judging conformity.
Therefore, as with existing authorization, it has been confirmed that even in any given location the density of radioactive materials on the surface of the package does not exceed the surface density regulatory limit set forth in Article 9 of the public notice: 0.4 Bq/cm2 for nuclides that emit alpha rays or 4 Bq/cm2 for nuclides that do not emit alpha rays.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 4 In design change, as with existing authorization, transport is done after (III)-A.2 paragraph 10 confirming that no items other than those necessary for the use of nuclear fuel materials are contained. Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 5 In design change, there is no change in the packaging structure, which will (I)-C (6) paragraph 2 be a condition for judging conformity.
Therefore, as with existing authorization, the package has the external dimensions greater than 10 cm as noted below.
1144 mm in length, 830 mm in width, and 1060 mm in height Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
II - G - 4
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 5 In design change, there is no change in the packaging structure and seal (II)-A.4.3 paragraph 3 utilization method, which will be conditions for judging conformity.
Therefore, as with existing authorization, the inner receptacle and the outer (III)-A.1 receptacle of the package are firmly connected with their respective lid by means of rod bolts. Tools such as wrenches must be used to loosen or tighten these rod bolts, and a crane or other hoisting devices is required to remove the lid of the outer receptacle. Thus, there is no risk of erroneous opening of the lid. Once the outer receptacle has been joined with the lid, a seal is applied to a zone covering both the lid and the body of the outer receptacle. In case that the outer receptacle is opened, the operation of opening becomes objectively visible.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
II - G - 5
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 5 In design change, there is no change in the packaging material, which will be (II)-B.4.6 paragraph 4 a condition for judging conformity. Therefore, as with existing authorization, (II)-A.4.2 the temperature range for this package expected during operation is -40°C to (II)-A 114°C, and materials used for components (stainless steel, aluminum, silicon Attachment 2 rubber, ceramic fiber, etc.) are not likely to crack or break in the temperature (II)-B.1 range expected during transport (-40°C to 114°C), as there is no significant (II)-B.3 reduction in strength or embrittlement, etc., and the required material strength, etc., is not affected.
Thus, there is no change to conformity of the package in the technical standards set forth in the regulations.
Article 5 In design change, there is no change in the packaging material and structure, (II)-A.4.6 paragraph 5 which will be conditions for judging conformity.
Therefore, as with existing authorization, when the ambient pressure drops to 60 kPa in absolute pressure, the maximum internal and external pressure difference of the inner receptacle is 63 kPa. However, the stress generated in the inner receptacle itself and in the rod bolts that firmly tighten the body and lid of the inner receptacle is smaller than the standard value, so no cracks, damage, etc., occur in the inner receptacle. Therefore, there is no risk of radioactive material leaking from the package.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 5 In design change, there is no change in the contents, which will be a condition (I)-D paragraph 6 for judging conformity.
Therefore, as with existing authorization, no liquid nuclear fuel is contained in this packaging, so the technical standards do not apply.
Article 5 In design change, there is no change in the packaging material, structure, and (II)-D.1 paragraph 7 contents, which will be conditions for judging conformity. (II)-D.2.1(2)
Therefore, as with existing authorization, conditions for highest source intensity are maximum storage volume (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle, and conservatively assuming that pellet storage box assembly including pellet storage box and borated stainless steel plate were not present, and considering the uranium isotope conditions where the source intensity is highest. After considering such conservative input, a shielding analysis using the QAD-CGGP2R code was performed, the dose equivalent rate on the external surfaces of the package is 0.028 mSv/h or less and will never exceed 2 mSv/h.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
Article 5 In design change, there is no change in the packaging material, structure, and (II)-D.1 paragraph 8 contents, which will be conditions for judging conformity.
Therefore, as with existing authorization, conditions for highest source intensity are maximum storage volume (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle, and conservatively assuming that pellet storage box assembly including pellet storage box and borated stainless steel plate were not present, and considering the uranium isotope conditions where the source intensity is highest. After considering such conservative input, a shielding analysis using the QAD-CGGP2R code was performed, the dose equivalent rate 1 m from the package is 2.56 µSv/h or less and will never exceed 100 µSv/h.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
II - G - 6
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 5 In design change, there is no change in the packaging structure and gross paragraph 9 weight, which will be conditions for judging conformity.
(I) Therefore, as with existing authorization, there is no leakage of radioactive material even when placed under the conditions listed in Article 13 of the public notice of the Notification on Technical Details for Off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: The Public Notice of the Science and Technology Agency No. 5, an extra of November 28, Article 13 1990, as shown below.
and Thus, there is no change to conformity of the package to the technical Appendix 3 standards set forth in the regulations.
(II)-A.5.2 Paragraph 1 (I) of Appendix 3 The outer shell of this packaging is covered with stainless steel plates and all joints are welded. The flange of the outer receptacle body is shaped to be one step higher on the inside to prevent rainwater from entering through the gap between the body and the lid. Therefore, there is no water penetration into the packaging due to water spray, and no material degradation occurs.
Therefore, even when placed under these conditions, the entire packaging, including the seal boundary, will not be damaged or cracked due to material deterioration, and there is no risk of radioactive material leakage.
Paragraph 1 (II) (1) of Appendix 3 (II)-A.5.3 In 1.2-m drops of prototype packaging, deformation of the prototype packaging was localized only on the impact surface and integrity was maintained. Therefore, even when placed under these conditions, the entire packaging, including the seal boundary, will not be damaged or cracked, and there is no risk of radioactive material leakage.
Paragraph 1 (II) (2) of Appendix 3 (I)-C The material and weight of the package are not classified by the items of this public notice.
Paragraph 1 (II) (3) of Appendix 3 (II)-A.5.4 Structural analysis was performed under loading conditions equivalent to five times the gross weight. And the results showed that the load on each part was below the buckling load, and no deformation occurs in the packaging.
Therefore, even when placed under these conditions, the entire packaging, including the seal boundary, will not be damaged or cracked, and there is no risk of radioactive material leakage.
Paragraph 1 (II) (4) of Appendix 3 (II)-A.5.5 A penetration test was conducted on the prototype packaging by dropping a 6 kg round bar from a height of 1 m. And the results showed no major damage was observed in the packaging, and integrity was maintained.
Therefore, even when placed under these conditions, the entire packaging, including the seal boundary, will not be damaged or cracked, and there is no risk of radioactive material leakage.
II - G - 7
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 5 In design change, there is no change in the packaging material, structure, paragraph 9 and contents, which will be conditions for judging conformity.
(II) Therefore, as with existing authorization, the maximum dose equivalent rate at the surface does not increase significantly and does not exceed 2 mSv/h, even when placed under the conditions listed in Article 13 of the public notice of the Notification on Technical Details for Off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: The Public Notice of the Science and Technology Agency No. 5, an extra of November 28, 1990, as shown Article 13 below.
and Thus, there is no change to conformity of the package to the technical Appendix 3 standards set forth in the regulations.
(II)-D.1 Conditions for highest source intensity are maximum storage volume (II)-D.3.1.2 (264 kg) of uranium dioxide with an enrichment of 5% in the inner receptacle, and conservatively assuming that pellet storage box assembly including pellet storage box and borated stainless steel plate were not present and considering the uranium isotope conditions where the source intensity is highest. After considering such conservative input, a shielding analysis using the QAD-CGGP2R code was performed upon conservatively assumption of compressive deformation of 5 mm in each direction as a dimensional change under normal test conditions, the dose equivalent rate on the external surfaces of the package is 0.0326 mSv/h or less and will never exceed 2 mSv/h. Moreover, the increase rate of the dose equivalent rate is approximately 17%.
Article 11 As in the description of technical standards in Article 3, subarticle 3, the (II)-F packaging is not affected by aging, and there is no impact on conformity to the technical standards set forth in the regulations.
II - G - 8
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 11 Article 23 In design change, there is no change in the contents, which will be a (I)-D condition for judging conformity.
Therefore, as with existing authorization, the package carries at least 15 g of uranium-235, so there is no change in the fact that the package is classified as fissile package in the technical standards.
Article 11 In design change, there is no change in the packaging structure and gross paragraph 1 weight, which will be conditions for judging conformity. Therefore, as with (I) existing authorization, the receptacle does not suffer any dent that might contain a 10-cm cube on any of its structural elements, even when placed under the conditions listed in Article 24 of the public notice of the Notification on Technical Details for Off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: The Public Notice of the Science and Technology Agency No. 5, an extra of November 28, 1990, as shown below.
Article 24 Thus, there is no change to conformity of the package to the technical and standards set forth in the regulations.
(II)-A.9.1.4 Appendix 11 Paragraph 1 (I) of Appendix 3 As described in Article 5 paragraph 9 (I), no material degradation due to water spray occurs inside or outside of the package. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (1) of Appendix 3 As described in Article 5 paragraph 9 (I), in 1.2-m drops of prototype packaging, deformation of the prototype packaging was localized, and the package does not suffer any dent that might contain a 10-cm cube on any of its structural elements. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (3) of Appendix 3 As described in Article 5 paragraph 9 (I), no deformation occurs in the packaging, even under loading conditions equivalent to five times the gross weight. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (4) of Appendix 3 As described in Article 5 paragraph 9 (I), a penetration test was conducted on the prototype packaging by dropping a 6 kg round bar from a height of 1 m. And the results showed no major damage was observed in the packaging, and integrity was maintained. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
II - G - 9
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 11 In design change, there is no change in the packaging structure and gross paragraph 1 weight, which will be conditions for judging conformity. Therefore, as with (II) existing authorization, each side of the circumscribed cuboid is at least 10 cm even when placed under the conditions listed in Article 24 of the Notification on Technical Details for Off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: The Public Notice of the Science and Technology Agency No.
5, an extra of November 28, 1990, as shown below.
Thus, there is no change to conformity of the package to the technical Article 24 standards set forth in the regulations.
and (II)-A.9.1.4 Appendix 11 Paragraph 1 (I) of Appendix 3 As described in Article 5 paragraph 9 (I), no material degradation due to water spray occurs inside or outside of the package. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (1) of Appendix 3 As described in Article 5 paragraph 9 (I), in 1.2-m drops of prototype packaging, deformation of the packaging was localized.
Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (3) of Appendix 3 As described in Article 5 paragraph 9 (I), no deformation occurs in the packaging, even under loading conditions equivalent to five times the gross weight. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
Paragraph 1 (II) (4) of Appendix 3 As described in Article 5 paragraph 9 (I), a penetration test was conducted on the prototype packaging by dropping a 6-kg round bar from a height of 1 m. And the results showed no major damage was observed in the packaging, and integrity was maintained. Therefore, even when placed under these conditions, each side of the circumscribed cuboid is at least 10 cm.
II - G - 10
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 11 Article 24 In design change, there is no change in the packaging material, structure, Article 25 and contents, which will be conditions for judging conformity.
Article 26 Therefore, as with existing authorization, there is no change to conformity Article 27 of the package to the technical standards set forth in the regulations, as Appendix 11 and shown below.
Appendix 12 Evaluation of an isolated system is encompassed by evaluation of an array system, since ingress of water into the inner receptacle is considered in (II)-E.3 evaluation of an array system.
Evaluation of an array system is based on an infinite number of transport limits, both when placed under normal and accident conditions of transport.
In modeling of packages placed under normal conditions of transport, the analytical model was conservative in that the shape and dimensions paragraph 2 were taken to be those of the actual product during normal transport, (I) to (V) and the materials of the finely shaped structural members such as frames, flanges, bolts, aluminum honeycombs, spacers, and insulation materials were ignored, thus the effect of neutron absorption was not considered.
In modeling of packages placed under accident conditions of transport, the same as with packages placed under normal conditions of transport, (II)-E.4 the materials of the finely shaped structural members such as frames, flanges, bolts, aluminum honeycombs, spacers and insulation materials were ignored, thus the effect of neutron absorption was not considered.
Based on a conservative model, deformation and pellet crushing obtained from drop tests were conservatively modeled.
For packages placed under normal and accident conditions of transport, with the external boundary of the analytical model as a specular reflection condition for the array system, analyzing with the KENO-V.a code resulted in an effective multiplication rate of at most 0.928 for packages placed under accident conditions of transport if a value three times the standard deviation is considered. The effective multiplication rate is less than 0.95, and criticality is not reached.
II - G - 11
Section in Section in Statements Correspondence Regulations Public Notice with Section in Application Article 11 In design change, there is no change in the packaging material, which will (II)-A.4.2 paragraph 3 be a condition for judging conformity. (II)-B.4.6 Therefore, as with existing authorization, there is no change in the fact that the package will not suffer cleft or fracture at temperatures ranging from -
40°C to +114°C, as was covered in the description of Article 5 paragraph 4 of regulations for the NRA Ordinance on off-Site Transportation of Nuclear Fuel Materials, etc. Issuance: Order of the Prime Minister's Office No. 57 of December 28, 1978.
Thus, there is no change to conformity of the package to the technical standards set forth in the regulations.
(II)-G-12
CHAPTER III - Handling and Maintenance of Nuclear Fuel Packages III-A. Handlings of Packages The following paragraphs will present typical handling methods for nuclear fuel packages. Since such packages must be used under the restrictions imposed on the local handling facilities in accordance with the laws, ordinances, regulations and various standards which are applied to the facilities, operations and handlings other than those presented below may be adopted as required. Fig. III-A-1 shows a typical flow of the package handling operations.
A.1. Loading (1) Preparation of Packagings and Associated Equipment and Materials Transport packagings whose functional integrity has been verified should be used. The functional integrity of pellet storage boxes and component elements of pellet storage box assembly should also be verified before use.
(2) Preparation of pellets of uranium oxides Verify that the pellets of uranium oxides to be contained in the packaging have characteristics and properties that conform to the specifications for the package.
(3) Preparation of pellet storage boxes Place the pellets of uranium oxides on the corrugated plates in order and place them in stack in the pellet storage box. As shock absorbers and anti-vibration elements, insert spacer blocks made of an organic polymeric material such as neoprene rubber or urethane foam in the gaps between the lid of the pellet storage box and the corrugated plates and between the corrugated plates.
Close the lid of the pellet storage box. At this moment, firmly seal the loaded pellet storage boxes in a plastic bag with a sealer or strips of adhesive tape as stipulated by the operational requirements at the local handling facility.
(4) Assembling pellet storage box assembly Stack the pellet storage boxes alternately with intermediate partitions on the lowermost partition, and then place the uppermost partition on them. Engage nuts in the pillars on their top and tighten the nuts. Spacer blocks made of an organic polymeric material such as neoprene rubber or urethane foam in the gaps may be inserted between the pellet storage box and the partition as required to minimize the effect of possible vibration on the storage boxes during transport.
The maximum number of pellet storage boxes should be placed in each pellet storage box assembly: twelve (12) boxes in pellet storage box assembly A or five (5) boxes in pellet storage box assembly B. If the number of prepared pellet storage boxes is less than the maximum for the assembly, the remaining space III - A - 1
should be filled with unloaded (empty) pellet storage box(es) or partition(s).
The pellet storage box assembly A consists of one lowermost partition, one uppermost partition and eleven intermediate partitions. The pellet storage box assembly B consists of one lowermost partition, one uppermost partition and four intermediate partitions. With either pellet storage assembly, the required number of partitions must be placed in the assembly in order to tighten it with the nuts on top of the pillars to complete the assembly. This is a constructional restriction.
An option of assembling is to assemble a pellet storage box assembly directly in the void of the inner receptacle of the packaging. In such cases, paragraph (5) Loading of pellet storage box assembly can be disregarded . If the inner receptacle has already been set in place in the void of the outer receptacle, paragraph (7) Loading of the inner receptacle can be disregarded.
(5) Loading of pellet storage box assembly Attach eye nuts to the tops of the pillars of one of the pellet storage box assemblies. Connect the hooks of a crane or a similar hoisting device to these eye nuts and place the pellet storage box assembly into the inner receptacle. Repeat this loading operation for another pellet storage box assembly. Once the two assemblies have been put in place, remove the eye nuts and cover the assembly with the assembly cover.
Regardless of the total quantity of pellets, two pellet storage box assemblies must be loaded in the inner receptacle. If only one loaded pellet storage box assembly has been prepared, another assembly loaded with either empty pellet storage boxes or partitions must be loaded into the inner receptacle.
(6) Assembling the inner receptacle Verify first that the O-ring has been installed on the flange of the inner receptacle loaded with two pellet storage box assemblies. Cover the body of the inner receptacle with the lid by means of a crane or a similar hoisting device. Otherwise, workers may manually hold the lid and place it on the body of the inner receptacle. Tighten the lid on the body of the inner receptacle by means of the sixteen (16) rod bolts and nuts with a uniform initial tightening torque of 44.1 Nm (450 kgcm).
(7) Loading of the inner receptacle Use a crane or similar hoisting device, with the hooks attached to the inner receptacle bars on the lid of the inner receptacle, to place the fully-loaded inner receptacle into the void of the outer receptacle.
Alternatively, the operations (5) Loading of pellet storage box assembly and (6) Assembling the inner receptacle can be substituted for this operation if the inner receptacle has been set in place in the void of the outer receptacle with the lids removed.
(8) Assembling the outer receptacle Verify first that the fully-loaded and sealed inner receptacle has been correctly placed in the outer receptacle. Cover the body of the outer receptacle with the lid by means of a crane or similar hoisting device. Tighten the lid on the body of the outer receptacle by means of the twenty (20) rod bolts and nuts with a uniform initial tightening torque of 44.1 Nm (450 kgcm). Apply a seal to the two specified zones on the outer receptacle flange.
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(9) Temporary storage or shipping Carefully transport the loaded package on a transport vehicle such as a forklift or pallet truck to the dedicated temporary storage area or the shipping area, and carry out the appropriate stowage operation for temporary storage or shipping.
Note: The pellet storage box, the pellet storage box assembly, the corrugated plate, and other elements comprising the package may be referred to by other terms in external handling facilities - for example:
pellet storage case, pellet storage case assembly, corrugated tray, etc.
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A.2. Pre-shipment Inspections of Package To ship packages to a site outside NFIs premises, the pre-shipment inspections shown in Table III-A-1 should be carried out as required before, during, and/or after the final loading operation onto the transport vehicle bound for external sites.
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Table III-A-1: Procedures of Package Pre-Shipment Inspections Category Method of Inspection Criteria for Judgment Visual Check visually the appearance of the package. There is no significant deformation or fracture that might Inspections affect the package capabilities.
Lifting Check visually the appearance of the lifting attachments on There is no deformation or cleft/cracking on the welds that Inspections the outer receptacle. might affect the strength of the lifting attachments Determine the gross weight of the package by adding the Gross weight of package: 1300 kg conservative reference weights or weighing results of the Weight pellet storage boxes, elements comprising the pellet storage Inspections box assemblies and included materials and the conservative reference weight of the packaging to the weighing results of the pellets of uranium oxides.
Inspect the surface density of the nuclides which emit Nuclides which emit rays: 0.4 Bq/cm2 Surface Density rays and those which do not emit rays on the package Nuclides which do not emit rays: 4 Bq/cm2 Inspections surface by an appropriate method (e.g. smear method).
Measure the gamma-ray dose equivalent rate on the On the package external surface: 2 mSv/h Dose Equivalent package external surface and at locations 1 m from the At locations 1 m from the package external surface: 100 Rate Inspections package external surface with an instrument appropriate Sv/h for the purpose such as a survey meter.
- 1. Check visually the appearance of the boronic stainless 1. There is no significant deformation, fracture, or steel plates before placing the contents in the inner displacement from the required initial position.
Subcriticality receptacle. 2. There is no deformation that might lead to significant Inspections
- 2. Check visually the appearance of the package. reduction in distance from the fuel zone of any neighboring package.
Check the appearance of the contents and appropriately in 1. Enrichment: 5 weigh percent various certificates*, records and other documents, 2. Kinds of enriched uranium verifying that the contents meet the requirements Enriched uranium (excluding regenerated enriched uranium stipulated in the applicable standard(s). in accordance with ASTM C996-04 ECGU):
232U 0.0001 µg/gU
- Note: If checking is based on a certificate which mentions 234U 10x103 µg/g235U numerical values and no actual measurements, it must be 236U 250 µg/gU verified through inspections that the certificate was issued 99Tc 0.01 µg/gU in a quality system or equivalent. For 236U < 125 µg/gU, 232U and 99Tc are excluded.
- 3. The weight of pellets of uranium oxides is:
264 kg-UO2 in pellet storage box assembly A 200 kg-UO2 in pellet storage box assembly B Contents
- 4. Appearance Inspections There is no significant deformation or fracture on the intermediate partitions (boronic stainless steel).
There is no significant deformation or fracture on the elements comprising the pellet storage box assemblies, with assemblies correctly assembled.
There are no items other than those necessary for the use of nucear fuel materials.
- 5. Number of pellet storage box assemblies contained Contains two pellet storage box assemblies.
- 6. other criteria Pellet storage box and pellet storage box assemblies have not been in use for over 80 years.
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A.3. Retrieving the Contents (1) Delivered in package Carefully transport the delivered packages on a vehicle such as a hoisting device (e.g., crane) or forklift to the temporary storage area (temporary storage before unpackaging) or the unpackaging area.
(2) Opening/removing the outer receptacle lid Loosen and remove the rod bolts firmly joining the lid of the outer receptacle to the body of the outer receptacle. Connect the hooks of a crane or a similar hoisting device to the lifting attachments on the lid of the outer receptacle, and remove the lid.
(3) Lifting the inner receptacle Connect the hooks of a crane or a similar hoisting device to the lifting attachments on the lid of the inner receptacle, carefully lift the entire inner receptacle and retrieve it from the outer receptacle. This operation is omitted if the operation described in step (4) Opening the lid of the inner receptacle is carried out in the outer receptacle (without retrieving/removing the inner receptacle from the outer receptacle).
(4) Opening the lid of the inner receptacle Loosen and remove the rod bolts joining the lid of the inner receptacle to the body. Remove the lid of the inner receptacle by means of a crane or similar hoisting device. Otherwise, workers should manually hold and remove the lid of the inner receptacle from the body of the inner receptacle.
(5) Lifting the pellet storage box assembly Attach eye nuts to the top of the pillars of one of the pellet storage box assemblies . Connect the hooks of a crane or similar hoisting device to these eye nuts, carefully lift the assembly and retrieve it from the inner receptacle. This operation is omitted if the operation described in step (6) Dismantling the pellet storage box assembly is carried out in the inner receptacle (without retrieving/removing the assembly from the inner receptacle).
(6) Dismantling the pellet storage box assembly Once the assembly cover has been removed, loosen and remove the nuts on top of the pillars of the pellet storage box assembly. Retrieve the partitions and the pellet storage boxes one after another. The removed pellet storage boxes are stored in the appropriate area in the handling facility.
(7) Reassembling the pellet storage box assembly Reassemble the pellet storage box assemblies either with empty pellet storage boxes and partitions or with partitions only. Place the assembly into the inner receptacle by means of a crane or similar hoisting device.
Place the assembly cover on the assembly. Alternatively, the pellet storage box assemblies may be assembled in the inner receptacle.
A crane or similar hoisting device should be used, or workers should manually hold the lid of the inner III - A - 6
receptacle, to place it on the body of the inner receptacle. Tighten the lid on the body of the inner receptacle with the rod bolts (it is not necessary to measure the tightening torque).
Place the inner receptacle into the outer receptacle by means of a crane or similar hoisting device. Cover the body of the outer receptacle with the lid, and tighten the lid on the body of the outer receptacle with the rod bolts (here too , it is not necessary to check the tightening torque). This operation is omitted if the inner receptacle has already been put in place in the void of the outer receptacle.
Carefully transport the loaded package on a transport vehicle such as a forklift or pallet truck to the dedicated storage area or the service area.
Note: The pellet storage box, the pellet storage box assembly, the corrugated plate, and other elements comprising the package may be referred to by other terms in external handling facilities - for example:
pellet storage case, pellet storage case assembly, corrugated tray, etc.
A.4. Preparation of Empty Packaging (1) Inspect transport packagings after use for surface contamination in the recovery procedure established in the handling facility, and decontaminate them as required. Transport the packagings to the storage or the service area for storage or maintenance work.
(2) After use, store the transport packagings indoors. If they have to be stored outdoors, take measures to protect them from direct exposure to the weather.
(3) To store a transport packaging temporarily, close the inner receptacle and the outer receptacle with the respective lid, tighten only the number of rod bolts required for handling. To avoid blockage, never apply excessive torque while tightening the rod bolts..
(4) Before a packaging operation, verify visually that the transport packaging has kept its original capabilities.
A.5. Other Notes Provided that the laws, ordinances, regulations, and other stipulations are not breached, an inner receptacle loaded with contents may be transported on a transport vehicle such as a forklift or pallet truck or with a hoisting device such as a crane from area to area within the perimeter of the facility as required.
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Empty packaging delivered in/Prepare a packaging Prepare contents (Prepare pellet storage boxes/Assemble pellet storage box assembly)
Pre-shipment Inspections (contents)
Package (Assemble and load the inner receptacle/Assemble the outer receptacle)
Pre-shipment Inspections (appearance, lifting, weight, surface density, dose equivalent rate, subcriticality)
Temporary storage Shipping Delivery Open the package (open outer receptacle lid, lift inner receptacle, open lid)
Retrieve contents (Lift and disassemble pellet storage box assembly)
Reassemble empty pellet storage box assembly Service or temporary storage Shipping empty packaging Fig. III-A-1: Example of Package Handling Flow III - A - 8
III-B. Maintenance Requirements Periodical voluntary inspections of the transport packaging are carried out at least once a year (or every ten transport missions of the packaging if the packaging is used for transport at least ten times a year). Table III-B-1 shows the procedures for periodical voluntary inspections. Table III-B-2 shows the procedure for periodical voluntary inspections required whenever the packaging is expected/planned to be stored without being used for at least one year in the same location.
The bolts and nuts, spacers, honeycomb elements and other parts which can be detached from and reattached to the transport packaging should be replaced with those of identical characteristics as required to maintain the capabilities of the packaging or as part of the maintenance operation. The lids and bodies of the inner/outer receptacle should be replaced as required to maintain the capabilities of the packaging or as part of the maintenance operation. O-ring should be replaced with new ones before transportation.
B.1. Visual Inspections Whenever the periodical voluntary inspections are carried out, the following items are visually checked:
- that the internal and external surfaces of the body and lid of inner and outer receptacle do not have any deformation or fracture that might affect the capabilities of the packaging;
- that the welds do not have any cracks or clefts;
- that the bolts and nuts do not have any deformation or fracture and that none of them has been lost;
- that the rubber materials such as spacers and skids do not present any deterioration, partial loss or displacement.
Packagings that are expected/planned to be stored without being used for at least one year in the same location should be subjected to these inspections, excluding those related to the interiors of the inner and outer receptacle. Shortly before use for transport at the end of such a long-term storage, such packagings should be subjected to all these inspections including those related to the interiors of the inner and outer receptacle.
B.2. Withstand Pressure Inspections Not applicable.
B.3. Leaktightness Capability Inspections Not applicable.
B.4. Shielding Capability Inspections Not applicable.
B.5. Subcriticality Inspections Whenever the periodical voluntary inspections are carried out, packagings should be inspected visually to verify:
- that the boronic stainless steel plates do not have significant deformation or fracture or present any III - B - 1
displacement from their required positions;
- that the inner and outer receptacle do not have any deformation that might lead to significant reduction in distance from the fuel zone of any neighboring package.
For packagings that are expected/planned to be stored without being used for at least one year in the same location, these visual inspections may be omitted. However, shortly before use for transport at the end of such a long-term storage, the packaging should be subjected to such visual inspections.
B.6. Thermal Capability Inspections Not applicable.
B.7. Lifting Capability Inspections Whenever the periodical voluntary inspections are carried out, visual inspections should be carried out to verify that the packaging has not suffered any deformation or cleft/crack in the welds that might affect the lifting attachments on the lids of the inner and outer receptacle.
For packagings that are expected/planned to be stored without being used for at least one year in the same location, these inspections may be omitted. However, shortly before use for transport at the end of such a long-time storage, such packaging should be subjected to the above visual inspections.
B.8. Operability Inspections Not applicable.
B.9. Maintenance of Ancillary Systems Not applicable.
B.10. Maintenance of Valves and Gaskets of Containment System Whenever the periodical voluntary inspections are carried out, visual inspections should be carried out to verify that the O-ring on the inner receptacle flange does not present significant deterioration or partial loss that might affect its leaktightness.
For packagings that are expected/planned to be stored without being used for at least one year in the same location, these inspections may be omitted. However, shortly before use for transport at the end of such a long-time storage, such packaging should be subjected to the above visual inspections. O-ring should be replaced with new ones before transportation.
B.11. Storage of Packaging Packagings that are expected/planned to be stored without being used for at least one year in the same location should be stored indoors. Once the storage period expires, or if the planned long-term storage is interrupted because of change of the storage location, all the inspections described in sections B.1. Visual Inspections, B.5. Subcriticality Inspections, B.7. Lifting Inspections and B.10. Maintenance of Valves and Gaskets of Containment System should be carried out.
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B.12. Storage of Records All the Inspection Records at Manufacturing Stage and the Periodical Voluntary Inspection Records are stored until the approval registration of the relevant packaging(s) is cancelled because no utilization plan is set for them.
B.13. Other Provisions None.
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Table III-B-1: Procedures for Periodical Voluntary Inspections Category Method of Inspection Criteria for Judgment Visual Inspections 1. Visually check the external and internal 1. There is no significant deformation or surfaces of the outer and inner receptacle fracture that might affect the and the lid. packaging capabilities.
- 2. Visually check the welds. 2. There are no cracks or clefts.
- 3. Visually check the bolts and nuts. 3. There is no deformation, fracture or
- 4. Visually check the rubber parts such as partial loss.
spacers and skids. 4. There is no significant deterioration, harmful partial loss or displacement from required position.
Subcriticalilty 1. Visually check the appearance of the 1. There is no significant deformation, Inspections boronic stainless steel plates in the inner fracture, or displacement from receptacle required position.
- 2. Visually check the appearance of the 2. There is no deformation that might packaging. lead to significant reduction in distance from the fuel zone of any neighboring package.
Lifting Inspections Visually check the appearance of the outer There is no deformation or cracks/clefts receptacle, the inner receptacle and the in the welds that might affect the lifting attachments on the inner receptacle. strength of any of the lifting attachments.
Maintenance of Visually check the inner receptacle flange. There is no significant deterioration or Valves and Gaskets partial loss that might affect the of Containment leaktightness of the packaging.
System Table III-B-2: Procedures for Periodical Voluntary Inspections Before Long-time Storage Category Method of Inspection Criteria for Judgment Visual Inspections 1. Visually check the external surfaces of the 1. There is no significant deformation or outer and inner receptacle and the lid. fracture that might affect the
- 2. Visually check the welds of the external packaging capabilities.
and internal surfaces of the outer and 2. There are no cracks or clefts.
inner receptacle.
- 3. Visually check the bolts and nuts on the 3. There is no deformation, fracture or outer receptacle. partial loss.
- 4. Visually check the rubber parts such as 4. There is no significant deterioration, spacers and skids on the external surfaces harmful partial loss or displacement of the outer receptacle. from the required position.
Note: These inspections are conducted only if a packaging is expected/planned to be stored in the same location for at least one year.
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CHAPTER IV - Special Notes on Safety Designing and Safe Transport None.
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