ML20137E699
| ML20137E699 | |
| Person / Time | |
|---|---|
| Site: | Framatome ANP Richland |
| Issue date: | 03/17/1997 |
| From: | Edgar J SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER |
| To: | Weber M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| JBE:97-040, JBE:97-40, TAC-L30940, NUDOCS 9703280187 | |
| Download: ML20137E699 (36) | |
Text
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,pr SIEMENS t sowo 1
March 17,1997 JBE:97:040 U.S. Nuclear Regulatory Commission Attn: Michael F. Weber, Chief Licensing Branch Division of Fuel Cycle Safety and Safeguards, NMSS
]P { 3 Washington, DC 20555
Dear Mr. Weber:
Enclosed for your information and to include in Chapter 15 of Siemens Power Corporation's (SPC) license application are two copies each of pages 15-31 through 15-31h,15-32 through 15-32h, and 15-33 through 15-33q. These pages provide summaries of criticality safety analyses for the Line 1 powder preparation system, the Line 2 and 3 powder preparation systems, and the pelletizing process.
If you require additional information, please call me at 509-375-8663.
Very truly yours, l
James E. Edgar Staff Engineer, Licensing
/pg Enclosures I
h i
- ~
9703280187 970317 PDR ADOCK 07001257 c
151,1ll11515,N,15,115E Siemens Power Corporation Nuclear Division 2101 Horn Rapids Road Tel:
(509) 375 8100 Engineering & Manufacturing P.o. Box 130 Fax:
{509) 375-8402 Richland, WA 99352-0130
Sl mens Power Corporation - Nuclear Division eur.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 PART 11 - SAFETY DEMONSTRATION
- nev, 15.1.8 Powder Preparation 15.1.8.1 Line 1 Powder Preparetion i
The Line 1 Powder Preparation Systems starts with the Line-1 blenders and ends in the bottom of the granulator hood. The equipment is located in Rooms 128 and 131 A of the UO Building. The raajor system components are:
2 I
1)
Line-1 (21 cubic foot) dry powder blender, download hood, and download screw feeder hopper; 2)
The Line-1 powder prep equipment; i.e., hammermill, ro!! compactor and granulator including the associated hoods; 3)
The Line-1 barrel download hood; and 4)
The vacuum transfer hood (add-back hood).
The function of the Line-1 powder preparation system is the blending, milling, compacting and granulating of UO, powder in preparation for pellet pressing. After UO, powder is calcined, it is vacuum transferred to slab hoppers and sampled for moderator content. After UO, powders in the slab hoppers are certified to contain accepta'le amounts of moderator based on laboratory analysis, the Line-1 slab o
hoppers' contents are vacuum transferred to the 21 cubic foot dry powder blender.
The vacuum transfer system uses room air for the transport inedium Certified dry UO, powder may also be vacuum transferred to the blender from 45-gallon barrel that is staged in the add-back hood for downloading. The powder is then blended prior to vacuum transfer to the hammermill. After the powder is m:lled, it is gravity fed to the roll compactor and granulator. The powder then falls through a transfer chute into 45-gallon barrel containing neutron absorbing inserts.
15.1.8.1.1 Criticality Safety Criticality safety for this system is dependent upon restricting the amount of I
moderating materials inside the equipment. Moderation and enrichment are the parameters controlled to prevent criticality in the blender and portions of the powder preparation equipment.
Geometry control is not practical for the blending and preparation portions of the operation due to the need to blend and prepare large volumes of material. With the controls on enrichment and moderation required, criticality safety criteria are met without requiring favorable geometry.
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PART (1 - SAFETY DEMONSTRATION REV.
21 Cubic Foot Drv Powder Blender t
Criticality safety in the blender is pradicated on maintaining the moisture content of i
the powder to 51 wt.%.
The total amount of moderator in the blender is also limited to a maximum of 9.5 kg.
l' Summarv of Accident Conditions There are two general accident scenarios involving moderation intrusion with respect to the blenders: one is getting moderator into the vicinity of the blender and the second involves actue.!!y gening moderator into the blender itself.
Room 128, where the blender is located, has no water sources inside the room, thus eliminating the possibility of liquid sprays. Use of water for fire fighting is prohibited in this area and is so identified. Water sources are available in the rooms adjacent to Room 125 so flooding into the room is possible. Liquid water detectors un the floor of Room 128 are interlocked to shut down the vacuum transfer system if water is present.
i' The blender is fabricated frem steel out is not totally enclosed in a secondary housing. Sample ports, inspection / maintenance ports and Vac-U-Max filter ports exist on the blender. Sample ports are opened only when samples are collected.
inspection / maintenance ports are opened only when the blenders are empty. During operation, all sample and inspection ports are normally closed both to prevent air from leaking into the blender (which could lead to powder oxidation) and to keep UO, powder from leaking out of the blender (which would lead to high airborne uranium concentrations).
The type of accident that has the greatest impact on criticality safety is getting moderation inside the equipment.
The two limiting conditions involving the blender are: (1) approximately 4.0 wt.%
. moisture uniformly distributed through a full blender of 4.0 g/cc UO, powder; and (2) approximately 19 kg of water that is optimally interspersed in a 36 cm diameter sphere of UO, that is reflected by dry UO, powder. During accident conditions, three methods exist for moderator intrusion into the vicinity of the blender and vacuum transfer lines. These are 1) liquid spray, 2) liquid floods, and 3) liquid carried in the air. There are six potential pathways in Room 128 for moderator to get into the blender. The six pathways, which do not include breaching the wall of the blender or deliberate opening of inspection / maintenance ports, are:
1 1)
Vacuum transfer lines into the blender.
2)
Vacuum relief line (rupture disc) located on the top of the blender.
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F 3)
N swesp system.
l 2
4)
Vacuum exhaust line.
5)
Blender drive system tubricant.
l 6)
With the powder from slab hoppers or barrels. This moderator could be in the form of additives added to the powder as part of the process.
Moderator Entrv via the Vacuum Transfer Lines Excess moderator can get into the blender by transferring powder with a high moderator content and by transferring moderator with the air used to transport the powder. The following defenses are in place to prevent such transfers:
The calcination process parameters are tightly controlled and normally the calciner produces powder with a moisture content between.05 and.35 wt.% water. A moisture monitor at the discharge end of the calciner will detect powder with a high moisture content.
Calcined powder is transferred to geometrically favorable slab hoppers, sampled, and confirmed by analysis to contain < 1.0 wt.%
water before being transferred from the slab hoppers.
I Uranium powders that contain moderating additives are not allowed in i
blenders or in hoods that have vacuum lines connected to blenders without written permission from Criticality Safety.
There are special controls on labeling and allowed storage locations for barrels of UO, with additives.
l Allowed amounts of additive in barrels will result in much less than l
1.0 wt.% moisture equivalent inside the blender if accidentally added f
with powder at normal moisture.
Each transfer line to the blender is equipped with a lockable valve I
which is locked at all times except for during a transfer of confirmed dry powder.
In addition, the following defenses are in place to preclude excess moisture in the vacuum transfer system:
f The air pickup points for the vacuum transfer lines into the blender are l
several inches above the floor and are located in hoods or on l AMENDMENT APPLCATON DATE:
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1 Siemens Power Corporation - Nuclear Division sup.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 PART 11-SAFETY DEMONSTRATION REV.
i i
I moveable vacuum wands that are attended by an operator during
- transfer, fl Vacuum transfer lines from the Line-1 calciner to the Line-1 slab hoppers are shielded from liquid sources.
No water sources are present in Room 128.
The vacuum pump is interlocked to' shut off if liquid is detected on the i
floor, high humidity is detected in the air, if the fire alarm sounds, or if a transfer operator leaves his work station during manual transfer, i
causing a thru-beam sensor to deactivate the vacuum pump.
Water for fire fighting is prohibited in Room 128.
r Moisture Entrv via the Vacuum Relief Line The pressure relief valve on the blender relieves at approximately 3 psi and is vented to the top of the blender download hood which is approximately 40 l
inches above the floor. It is not credible to get water into the blender via this route because the valve is only open if the blender is at a higher pressure than the room and because, if the valve failed open, water would have to be greater than 40 inches deep in the room to reach the bottom of the vent.
Moderator Entrv via the N _SWeeD System i
2 The following defenses prevent the addition of water into the blender via the N system:
2 A change control system that includes overview and functional checks to ensure correct installation, thus precluding accidentally l-connscting a water line to the N system.
2 l
The N line pressure is greater than plant water pressure and the line 2
is interlocked to shut off flow to the blender upon detection of low N2 l
pressure.
i t
The N system is routed through a moisture detecting instrument that 2
i is interlocked to shut off N flow if moisture is detected, 2
i s
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' REV. i i
i Moderator Entry via the Vacuum Exhaust Svstem The vacuum exhaust lines from Room 128 discharge to an exhaust system that has a deluge system for fire protection.
The exhaust system was evaluated for potential backflow to the Line-1 blender and powder preparation equipment. A four-inch drain on the exhaust system will prevent water from accumulating to significant depths in the ductwork. If this drain were to plug, before water could get to Room 128, it would drain through a 16-inch duct that connects to the bottom of the main plenum to an open filter box in Room 100. If water were somehow able to get past this 16-inch duct, it would eventually accumulate in a filter box in Room 128 and drain into the slab hopper download hood and/or into the vacuum transfer hood and onto the floor where liquid detectors would alarm and shut off the vacuum transfer system.
Moderator Entry via the Blender-Drive System The blender drive system contains halocarbon oils and grease. Small amounts of lubricant leaking into the blender are anticipated. There are several defenses that prevent large amounts of hydrogenous lubricant from entering the blender.
Enrichment cleanout (ECo) inspections will detect significant leaks of lubricant, r
Only trained and authorized maintenance personnel are allowed to service the blender.
The PM procedure clearly specifies and the blenders are clearly posted that only halocarbon lubricants may be used in the blender drive mechanism.
The lubricant used in the blender has a controlled release to ensure it is not mixed with other lubricants.
Moderator Entrv via Powder from Slab Hoooers or Barrels See the discussion under " Moderator Entry via Vacuum Transfer Lines".
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' Rev.
Line-1 Powder Preoaration Ecuioment (Hammermill, Roll Comoactor and i
Granulator) l limiting moderation in the UO, to a maximum of 1 wt.% water, C i Summary of Accident Conditions There are two levels of moderator intrusion of concern with the powder preparation equipment - intrusion into the vicinity of the equipment and intrusion into the equipment itself.
Moderator can get into the vicinity of the powder preparation equipment only if an accident such as a broken process water or steam line or a roof or roof drain leak occurs. Such an accident would result in a spray, a flood or supersaturated air.
least two independent, separate accidents must occur to mix powder and At moderators. The accident that allowed the moderator into the vicinity would have breached one barrier such as the pipe wall containing the fluid or the roof or roof l drain, but two additional barriers, the powder preparation equipment and Lexan enclosures, remain to keep moderators out of the UO,.Conversely, if an accident occurs that allows UO, powder to leak from the blending and powder preparation equipment, one barrier is lost, leaving two additional barriers, the liquid containing equipment (piping, tanks, etc.)
remaining to keep powder and moderators separated.and Lexan enclosures around the eq Moderator intrusion into the powder preparation equipment can occur by one of the four paths presented below, with the associated defenses.
Moderator intrusion into the powder preparation equipment with the powder was considered.
The defense against such intrusion is that powders containing additives are only allowed in the powder preparation equipment under special conditions including ensuring the total water and water equivalent approved additive is less than 1.0 t
wt.% on a double contingency permission by the Criticality Safety Specialist. basis and by requiring written Moderator intrusion into the powder preparation equipment with the air used to transport the powder was considered.
The defenses against such intrusion are:
(1) the air inlets to the vacuum transfer system are located inside Lexan enclosures; (2) liquid and high humidity detectors as well as the fire alarm system are interlocked to
)
shut down the vacuum transfer system any time liquid or high
}
{
humidity conditions are detected; (3) the vacuum wands used by the I
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PART 11 - SAFETY DEMONSTRATION REv. !
1 i
operators to transfer powder are located in Room 128 vhere no !
sources of moderation exist inside the room; and (4) liquid detectors ;
I i
will shut down the equipment if liquid is present on the floor of Room 128.
Moderator intrusion directly through leaks in the equipment, or through piping / routing errors was considered. The defenses against such intrusion are:
(1) other than limited volumes of equipment lubricants, no moderators are piped into the powder preparation l
enclosures and (2) the plant configuration control system prevents unreviewed changes.
Powder moderation from equipment lubrication was considered. The defenses against such moderation are: (1) the volume of lubricant is small with 8-10 oz. per system, therefore, an 18 kg addition in short term is incredible; (2) the hammermill has a double lip seal with drain (reservoir is outside, but line goes inside); (3) the roll compactor i
granulator drive box reservoirs are outside the hood; (4) sealed i
bearings are used on the roll compactor and granulator; (5) surveillance is performed on each shift on the hammermill screen; and (6) operators who maintain lubricant levels are trained to watch for excessive lubricant leaking into powder preparation equipment.
Another accident condition of concern is powder spills. The UO, powder processed in the powder preparation equipment is required to be certified less than 1.0 wt.%
moisture. UO powder with this moisture content cannot go critical with 5.0 wt.%
enriched uranium. Spills of UO, powder are a concern because of the increased risk of becoming moderated. Therefore, powder spills onto floors or into enclosures must be cleaned up immediately. Equipment is designed to minimize spills.
Vacuum Transfer Hood and Barrel Download Hood
! The Line-1 vacuum transfer hood (add-back hoods) is large enough to enclose 45-I gallon barrel and is used to aid in vacuum transferring certified dry powder to the r
Line-1 blender or to the barrel download hood. The barrel download hood encloses a vacuum transfer hopper and can also enclose a 45-gallon barrel that is receiving i
certified dry powder from the slab hoppers, blender, or a 45-gallon barrel located in the add-back hood.
i Summarv of Accident Conditions The accident that has the greatest impact on criticality safety is getting moderation
- inside the equipment. Room 128 has no water sources inside the room; however aussoutsT appuccou ous
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PART 11 - SAFETY DEMONSTRATION i
nev. !
water sources are available in the adjacent rooms. 45-gallon barrels of UO, powder ll are frequently used inside hoods in this room.
The barrels all have neutron absorbing inserts that ensure any amount of uranium in a single barrel will be suberitical even in the event of moderating the barrel contents.
i System Interaction With Other Eauinment and Storaae Arrays
! with other process vessels through the ventilation system.The powd The dry powder hoods exhaust through an exhaust system which does not share any connections with solution bearing systems. Backflow of liquid from the offgas deluge system was previously discussed.
15.1.8.1.2 Radiation Protection Powder preparation is performed in a controlled access radiation controlled area.
Personnel entering or working in the area, who require monitoring under 10 CFR 20.1502(a), are required to wear radiation monitoring devices and protective l clothing / equipment (rubber shoe covers or equivalent, plastic gloves, coveralls, eye protection, respiratory protection) as appropriate for the work to be performed.
Personnel are required to survey themselves prior to exiting the controlled area.
Equipment leaving the controlled area must be released by Radiological Safety personnel. All personnel also receive initial and yearly refresher training on radiation protection principles and requirements.
l Airborne uranium contamination is controlled by extensive use of hoods which are maintained at negative pressure and HEPA filtered prior to entering the main exhaust ductwork. Examples of such hoods are powder download and lube addition.
Routine surveys are performed and housekeeping practices are enforced to minimite
~
surface and eirborne contamination in the powder preparation area.
Air is j
l continuously sampled and periodically analyzed to detect any airborne j
I.
contamination.
Urine sample analyses and lung counts are periodically performed for personnel who l
l work in the controlled access area. The frequencies of such tests are described in Chapter 3.
j t
4 l
l i
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SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 i*
PART 11 -SAFETY DEMONSTRATION l asv. !
i 15.1.8.1.3 Fire Protaction I
I I
The UO building is rated as noncombustible. Fire loading is kept to a minimum 2
through monthly inspections. Fire extinguishers (dry chemical or CO ), alarm pull 2
boxes, and heat detectors are strategically placed throughout the powder preparation area. Where moderation control is in place, high expansion foam, dry chemical or CO are required to be used to combat a fire.
2 15.1.8.1.4 Environmental Safety Hazardous materials are contained to prevent their introduction into. the environment. Hoods are maintained at a negative pressure and HEPA filtered prior to entering the main exhaust ductwork. Floors are sealed and have no drains.
All room and building air is processed through the heating, ventilation, and air conditioning system and then HEPA filtered to remove particulates.
Solvent rags from the controlled area are disposed of in special containers
' distributed throughout the powder preparation area. The rags are treated as mixed I
hazardous waste and stored in a secured area for future disposal.
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15.1.8 Powder Preparation I
15.1.8.2 Line 2 and 3 Powder Preparation The Line 2 and 3 Powder Preparation Systems start with the Line-2 and 3 blenders and end in the bottoms of the granulator hoods. The equipment is located in Room 104A of the UO Building. The major system components are:
2 1)
Line-2 and 3 (21 cubic foot) dry powder blenders and Line-2 download I
hood and download screw feeder hopper; 9'
The Line-4 (63 cubic foot) dry powder blender (so called because it is the fourth blender in the powder preparation system);
3)
Line-2 and 3 powder prep equipment; i.e.,
hammermills, roll compactors and granulators including the associated hoods; 4)
NFl and Line-3 download hoods; 5)
The Line-4 barrel download hood; and 6)
The Line-2 and 3 central vacuum system.
The function of the Line-2 and 3 powder preparation systems is the blending, milling, compacting and granulating of UO, powder in preparation for pellet pressing.
After UO, powder is calcined, it is vacuum transferred to slab hoppers and sampled for moderator content. After UO, powders in the Line-2 and 3 slab hoppers are certified to contain acceptable amounts of moderator based on laboratory analysis, slab hoppers' contents are vacuum transferred to the Line 2 and 3 21 cubic foot dry powder blenders. The vacuum transfer system uses room air for the transport medium. Certified dry UO, powder may also be vacuum transferred to the blenders from 45-gallon barrels that are staged in the add back hoods for downloading.
Powder may also be transferred from 45-gallon barrels into smaller containers for storage or shipment in the NFl and Line 3 inverted barrel download hoods. The Line-4 63 cubic foot dry powder blender can receive certified dry UO, powder only from the Line-2 and/or Line-3 blender (s). The powder is blended prior to vacuum transfer to the Line-2 and 3 powder preparation equipment. After the powder is milled, it is
{ gravity fed to roll compactors and granulators. The powder then falls throu0h
! transfer chutes into 45-gallon barrels containing neutron absorbing inserts.
15.1.8.2.1 Criticality Safety Criticality safety for this system is dependent upon restricting the amount of moderating materials inside the equipment. Moderation and enrichment are the parameters controlled to prevent criticality in the blender and portions of the powder preparation equipment.
Geometry control is not practical for the blending and preparation portions of the operation due to the need to blend and prepare large AMENOMENT APPUCATON DATE:
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volumes of material. With the controls on enrichment and moderation required, criticality safety criteria are met without requiring favorable geometry.
1 21 and 63 Cubic Foot Drv Powder Blenders I
e Criticality safety in the blenders is predicated on maintaining the moisture content of i! the powder to s1 wt.%.
The total amount of moderator in the blender is also limited to a maximum of 9.5 kg.
Summarv of Accident Conditions There are two general accident scenarios involving moderation intrusion with respect to the blenders: one is getting moderator into the vicinity of the blenders and the second involves actually ge'. ting moderator into the blenders themselves.
Room 104A, where the blenders are located, has several water sources inside the room, thus providing the possibility of liquid sprays and flooding in the room. Use of water for fire fighting is prohibited in this area and is so identified. The vacuum transfer system is interlocked to shut down any time the fire alarm activates, in addition, liquid water detectors on the floor of Room 104A are interlocked to shut down the vacuum transfer system if water is present. Hood floors are elevated to prevent moderating U powder that could potentially spillinside the enclosures.
The blenders are fabricated from steel but are not totally enclosed in secondary housings. Sample ports, inspection / maintenance ports and Vac-U-Max filter ports exist on the blenders. Sample ports are opened only briefly by an operator when samples are collected. Inspection / maintenance ports are opened only when the blenders are empty. During operation, all sample and inspection ports are normally l
closed both to prevent air from leaking into the blenders (which could lead to powder oxidation) and to keep UO, powcar from leaking out of the blenders (which would lead to high airborne uranium concentrations).
The type of accident that has the greatest impact on criticality safety is getting i
I moderation inside the equipment.
The two limiting conditions involving the blenders are: (1) approximately 4.0 wt.%
~ moisture uniformly distributed through a full blender of 4.0 g/cc Uo, powder; and (2) approximately 19 kg of water that is optimally interspersed in a 36 cm diameter sphere of UO, that is reflected by dry UO, powder. During accident conditions, j
three methods exist for moderator intrusion into the vicinity of the blender and vacuum transfer lines. These are 1) liquid spray, 2) liquid floods, and 3) liquid carried in the air. There are six potential pathways in Room 104A for moderator to AMENDMENT APPUCATION DATE:
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get into the blender. The six pathways, which do not include breaching the wall of the blender or deliberate opening of inspection / maintenance ports, are:
1)
Vacuum transfer lines into the blenders; 2)
Vacuum relief line (rupture disc or PRV) located on each blender or blender exhaust line; 3)
N sweep system; 2
4)
Vacuum exhaust line; 5)
Blender drive system lubricant; and f
6)
With the powder from slab hoppers or barrels (the Line-4 blender only receives powder from the Line 2 and/or 3 blenders). This moderator could be in the form of additives added to the powder as part of the process or foreign material vacuum transferred into the slab hoppers.
Moderator Entrv via the Vacuum Transfer Lines Excess moderator can get into the blenders by transferring powder with a high moderator content and by transferring moderator with the air used to transport the powder. The following defenses are in place to prevent such transfers:
The calcination process parameters are tightly controlled and normally the calciner produces powder with a moisture content between.05 and.35 wt.% water. A moisture monitor at the discharge end of the calciner will detect powder with a high moisture content.
Calcined powder is transferred to geometrically favorable slab hoppers, sampled, and confirmed by analysis to contain < 1.0 wt.%
water by two independent methods before being transferred from the slab hoppers.
l Uranium powders that contain moderating additives are not allowed in i
blenders or in hoods that have vacuum lines connected tu blenders I
without written permission from Criticality Safety.
l There are special controls on labeling and allowed storage locations for barrels of Uo, with additives.
Allowed amounts of additive in barrels will result in much less than 1.0 wt.% moisture equivalent inside the blender if accidentally added with powder at normal moisture.
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PART 11 -SAFETY DEMONSTRATION REv.
Each transfer line to the blender is equipped with a lockable valve which is locked at all times except for during a transfer of confirmed dry powder.
In addition, the following defenses are in place to preclude excess moisture in the vacuum transfer system:
The air pickup points for the vacuum transfer lines into the blenders are several inches above the floor and are located in hoods or on moveable vacuum wands that are attended by an operator during i
transfer.
Vacuum transfer lines from the Line-2 calciner to the Line-2 and 3 s hoppers are not near liquid sources.
The vacuum pumps are interlocked to shut off if liquid is detected on the floor, high humidity is detected in the air, if the fire alarm sounds or if the transfer operator leaves his work station during rnanual j
transfer, causing a thru-beam sensor to deactivate the vacuum pump Water for fire fighting is prohibited in Room 104A.
Moisture Entry via the Vacuum Relief Line A pressure relief device on each blender or blender exhaust line relieves at approximately 3 psi and is piped to the top of the blender download hood. It is not credible to get water into the blenders via this route because the relief device is only open if the blenders are at a higher pressure than the room and because, if open, water would have to be several feet deep before it could enter the vacuum relief line.
Moderator Entrv via the N, Sweep System i
j The following defenses prevent the addition of water into the blenders via the N, system:
I A change control system that includes overview and functional checks to ensure correct installation, thus precluding accidentally connecting a water line to the Na system.
The N line pressure is greater than plant water pressure and the line 2
is interlocked to shut off flow to the blenders upon detection of low N pressure, 2
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The N system is routed through a moisture detecting instrument that is interlocked to shut off N flow if moisture is detected.
2 Moderator Entry via the Vacuum Exhaust System The vacuum exhaust lines from Room 104A discharge to the K-31 exhaust system. The K-31 exhaust system has a deluge system for fire protection.
Any time the deluge system activates, the fire alarm sounds. The deluge system was evaluated.for potential backflow to the Line-2 and 3 blenders and powder preparation equipment and the Line-4 blender. A two-inch drain on the exhaust system should prevent water from accumulating to significant i
depths in the ductwork. If this drain were to plug, before water could get into hoods requiring controls on moderators, the water would have to be over 5 feet deep and fail to drain out of the K-31-17-8, K31-17-14, and K-31 -
- 12 room vents. If liquid is detected on the floor of Room 104a and/or the floor of any hoods containing liquid detectors, they will alarm and shut off the vacuum transfer system.
Moderator Entry via the Blender-Drive System f
The blender drive systems contain halocarbon oils and grease. Small amounts of lubricant leaking into the blenders are anticipated. There are several defenses that prevent large amounts of hydrogenous lubricant from entering the blender.
Enrichment cleanout (ECO) inspections will detect significant leaks of lubricant.
Only trained and authorized maintenance personnel are allowed to service the blenders.
The PM procedure clearly specifies and the blenders are clearly posted that only halocarbon lubricants may be used in the blender drive I
mechanisms.
{
The lubricant used in the blenders has a controlled release to ensure it l
is not mixed with other lubricants.
Moderator Entrv via Powder from Slab Hoopers or Barrels See the discussion under Moderator Entry via Vacuum Transfer Lines".
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-f257 eup.2 PART 11 - SAFETY DEMONSTRATION REV. t I
Line 2'and 3 Powder Precaration Eauioment (Hammermills. Roll Comoactors and e
i Granulatorsi Criticality safety in the Line-2 and 3 powder preparation equipment is predicated upon limiting moderation in the Uo, to a maximum of 1 wt.% water.
Summarv of Accident Conditions There are two levels of moderator intrusion of concern with the powder preparation equipment - intrusion into the vicinity of the equipment and intrusion into the
} equipment itself.
Moderator can get into the vicinity of the powder preparation equipment only if an accident such as a broken process water or steam line or a roof or roof drain leak occurs. Such an accident would result in a spray, a flood or supersaturated air. At s
. least two independent, separate accidents must occur to mix powder and I
moderators. The accident that allowed the moderator into the vicinity would have
, breached one barrier such as the pipe wall containing the fluid or the roof or roof f drain, but two additional barriers, the powder preparation equipment and Lexan i
enclosures, remain to keep moderators out of the Uo,. Conversely, if an accident occurs that allows UO, powder to leak from the blending and powder preparation
- equipment, one barrier is lost, leaving two additional barriers, the liquid containing i equipment (piping, tanks, etc.) and Lexan enclosures around the equipment, remaining to keep powder and moderators separated.
Moderator intrusion into the powder preparation equipment can occur by one of the four paths presented below, with the associated defenses.
Moderator intrusion into the powder preparation equipment with the j
powder was considered. The defense against such intrusion is that powders containing additives are only allowed in the powder preparation equipment under specia! conditions including ensuring the i
total water and water equivalent approved additive is less than 1.0 l
wt.% on a double contingency basis and by requiring written i
permission by the Criticality Safety Specialist.
l Moderator intrusion into the powder preparation equipment with the air used to transport the powder was considered.
The defenses against such intrusion are: (1) the air inlets to the vacuum transfer system are located inside Lexan enclosures; (2) liquid and high i-humidity detectors as well as the fire alarm system are interlocked to shut down the vacuum transfer system any time liquid or high 5 AMENOMENT APPUCATON DATE:
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PART ll-SAFETY DEMONSTRATION REV. !
l humidity conditions are detected; (3) liquid detectors will shut down.
the equipment if liquid is present on the floor of Room 104A.
l Moderator intrusion directly through leaks in the equipment, or through piping / routing errors was considered. The defenses against such intrusion are:
(1) other than limited volumes of equipment lubricants, no moderators are piped into the powder preparation enclosures and (2) the plant configuration control system prevents unreviewed changes.
Powder moderation from equipment lubrication was considered. The i
defenses against such moderation are: (1) the volume of lubricant is small with 8-10 oz per system, therefore, an 18 kg addition in short term is incredible; (2) the hammermill has a double lip seal with drain (reservoir is outside, but line goes inside); (3) the roll compactor granulator drive box reservoirs are outside the hood; (4) sealed bearings are used on the roll compactor and granulator; (5) surveillance is performed on each shift on the hammermill screen; and j
(6) operators who maintain lubricant levels are trained to watch for excessive lubricant leaking into powder preparation equipment.
Another accident condition of concern is powder spills. The UO, powder processed in the powder preparation equipment is required to be certified less than 1.0 wt.%
moisture. UO powder with this moisture content cannot go critical with 5.0 wt.%
2 enriched uranium. Spills of UO, powder are a concern because of the increased risk of becoming moderated. Therefore, powder spills onto floors or into enclosures must be cleaned up immediately. Equipment is designed to minimize spills, Vacuum Transfer Hoods and Barrel Download Hoods e
The Line-2 and 3 vacuum transfer hoods (add-back hoods) are large enough to I enclose 45-gallon barrels and are used to aid in vacuum transferring certified dry i powder to the Line-2 and 3 blender or to the barrel download hoods. The Line 2
! barrel download hood encloses a vacuum transfer hopper and can also enclose a 45-barrel that is receiving certified dry powder from the slab hoppers, blender, or a 45-I gallon barrel located in the add-back hood. The NFl and Line-3 inverted barrel download stations consist of a feed hopper connected to a powder transfer system.
A cone is placed on top of a 45-gallon powder barrel which contains neutron absorbing inserts. The barrel is then inverted and placed into location above the feed hopper and the powder flows into the cone. The cone valve is opened and powder flows into the feed hopper.
Powder is then transferred into smaller containers for storage or shipment.
As described earlier, the Line-4 blender transfers only to the Line 2 and 3 powder preparation equipment.
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Siernens Power Corporation - Nuclear Division sup.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1'257 Ij REv. '
PART (1 - SAFETY DEMONSTRATION I
Summarv of Accident Conditions The accident that has the greatest impact on criticality safety is getting moderator !
inside the equipment. Room 104A has water sources inside the room and there are also water sources aveliable in the adjacent rooms. 45-gallon barrels of UO, powder are frequently used inside hoods in this room.
The barrels all have neutron absorbing inserts that ensure any amount of uranium in a single barrei will be suberitical even in the event of moderating and reflecting the barrel contents.
System interaction With Other Eouioment and Storaae Arrays e
The powder preparation system was evaluated for potential accident interactions with other process vessels through the ventilation system. The dry powder hoods
- xhaust through an exhaust system which does not share any connections with solution bearing systems. Backflow of liquid from the offgas deluge system was previously discussed.
15.1.8.2.2 Radiation Protection Powder preparation is performed in a limited access radiation controlled area.
Personnel entering or working in the area, who require monitoring under 10 CFR
- 20.1502(a), are required to wear radiation monitoring devices and protective clothing / equipment (rubber shoe covers a equivalent, plastic gloves, coveralls, eye protection, respiratory protection) as appropriate for the work to be performed.
Personnel are required to survey themselves prior to exiting the controlled area.
~
Equipment leaving the controlled area must be released by Radiological Safety personnel. All personnel also receive initial and yearly refresher training on radiation protection principles and requirements.
i Airborne uranium contamination is controlled by extensive use of hoods which are
- mainteined at negative pressure and HEPA filtered prior to entering the main exhaust
! ductwork. Examples of such hoods are powder download and lube addition.
l Routine surveys are performed and housekeeping practices are enforced to minimize surface and airbome contamination in the powder preparation area.
Air is i continuoucly sampled and periodically analyzed to detect any airborne contamination.
' Urine sample analyses and lung counts are periodically performed for personnel who work in the controlled access area. The frequencies of such tests are dcscribed in Chapter 3.
I I
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SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 701257 i
PART 11 - SAFETY DEMONSTRATION
!. arv. ei
.I i
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.j 15.1.8.2.3-Fire Protection i
i t
i The UO building is rated as noncombustible. Fire loading is kept to a minimum 2
through monthly inspections. Fire extinguishers (dry chemical or CO ), alarm pull 2
boxes, and heat detectors are strategically placed throughout the powder preparation area. Where moderation control is in place, high expansion foam, dry chemical or CO are required to be used to combat a fire.
2 15.1.8.2.4 Environmental Safety i
- Hazardous materials are contained to prevent their introduction into the environment. Hoods are maintained at a negative pressure and HEPA filtered prior j to entering the main exhaust ductwork. Floors are sealed and have no drains.
t All room and building air is processed through the heating, ventilation, and air
- conditioning system and then HEPA filtered to remove particulates.
I i
l Solvent rags from the controlled area are disposed of in special containers distributed throughout the powder preparation area. The rags are treated as mixed
)
hazardous waste and stored in a secured area for future disposal.
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4 4
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l SiemenS Powbr Corporation - Nuclear Division sup.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 l
PART ll-SAFETY DEMONSTRATION nev.
15.1.9 Pelletizina The pelletizing operation begins with lube blending in Room 180 and includes pressing, sintering, grinding and inspection of UO pellets in Room 100 of the UO Building.
2 2
j 15.1.9.1 Lube Blendina The Lube Blend Room is principally used for the proportioning, mixing, and blending of
! uranium oxide (UO ) powder with additives required for pressing.
In the blending 2
operation, which takes place in hoods, the required amounts of additives are weighed, added to poisoned 45 gallon barrels or 5 gallon buckets (safe batch containers) of prepped UO powder, and mixed in the barrei blender or the bucket tumbler. Blended powder is 2
then moved to the press feed queue or to the single specified bay for blended powder in the powder storage warehouse attached to the UO Building.
2 Some enrichment blending is also done in this room. Buckets of tious enrichments of powder are used to make up a barrel, which ;s tumbled in the barrel blender and returned to storage or sent directly to a powder preparation line.
Additionally, filters are cleaned in utility hoods located in this room. Filters are vacuumed, the contents being drawn into a vacuum filter canistet on the floor next to the hood.
The major components in this room are:
- 1) Three hoods that each have a lu% addition section and a utility section where filters are cleaned;
- 2) Barrel blender;
- 3) Five gallon bucket tumbler (holds two buckets); and
- 4) Queuing station for buckets and barrels.
15.1.9.1.1 Criticality Safety Criticality safety in the Lube Blend Room is maintained by controlling enrichment and limiting moderation in the UOx powder to s 1% water plus s 1% water equivalent of the additives used for pressing. In addition the 5 gallon buckets are limited to a safe batch and the 45 gallon barrels are fitted with fixed neutron absorbers.
Hoods - Lube Addition and Utility Sections Control of enrichment and moderator and the presence of neutror, absorbers (in barrels) assure criticality safety in the hoods in the Lube Blend Room.
L AVENOMENT APPLICATION DATE:
. P AGE NO :
March 17,1997 15-33 SPC ND 3330 947 (A 9 07 92:
SiemenS Power Corporation - Nuclear Division Eur.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 PART 11 - SAFETY DEMONSTRATION RE7 Summarv of Accident Conditions An accident condition involves a 45-gallon barrel with moderated contents and no neutron-absorbers in the insert or no insert The first defense requires that the fabrication /QA process assure that no single failure will result in a barrel being fabricated without the required neutron absorber present. In addition, a program of periodic checks is in place to confirm the continued presence of neutron absorber in the barrels. The second c'efense j requires that barrelloading procedures assure that the contents of all barrels have at least one confirmation that the barrels contain s 1.0 wt% moisture before additives are added in the Lube Blend room.
Barrel and Bucket Blenders and Queuino Stations Enrichment and moderation control and the presence of neutron absorbers (in barrels) assure criticality safety in these stations.
Summarv of Accident Conditions Several accident conditions concern spills from either buckets or barrels. A spill from a J
l bucket may be from a tipped container or due to a breach in the container. The first defense is the fact that the bucket is limited to a safe batch. The second defense is the fact that liquid sources are extemal to this room and therefore are unavailable to moderate a spill. In addition, an operator's trained responses to powder spills will minimize the time powder would remain on the floor.
A spill from a 45-gallon barrel may be from a tipped barrel or due to a breach. A tipped container may be caused by the barrel falling off of the various equipment used to move the barrel through the process. The first defense is the fact that a loaded barrel is required to have the lid installed and clamped in place unless the barrel is in a hood or other stab e location. in addition, carts, lifts and blenders have restraints to prevent a barrel from falling, and conveyors are tilted back to prevent forward falls. The second defense is the fact that liquid sources are extemal to this room and therefore are unavailable to moderate j a spill. In addition, an operator's trained responses to powder spills will minimize the time powder would remain on the floor.
Another method for a spill to occur is to have a breach in a barrel. The first defense against this is the fact that the cart carrying the barrel, which is driven by a trained operator, does not attain enough speed to breach a barrel, which is protected by the cart's frame / mass, in the event of a collision. The second defense is the lack of available liquid sources for moderation.
4
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j Siemens Power Corporation - Nuclear Division sup.2
., SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM 1227, NRC DOCKET NO. 701257 i
PART 11 - SAFETY DEMONSTRATION
' REv.
i i
l Another accident involves overbatching of the allowed additives in a 5-gallon bucket or a l
45-gallon barrel. For a bucket, the first defense is the fact that the bucket is limited to a l
safe batch. The second defense is the fact that reaching minimum critical moderation would require more than a five-times moderator overbatch.
For the scenario of overbatching the allowed additives to a 45-gallon barrel, the first defense is the presence of the boron-filled insert. The second defense is again that reaching the minimum critical moderation would require more than a five-times moderator overbatch.
The last set of accidents concerns the intrusion of moderator into a bucket or barrel through the top of the container or through a breach. For both of these conditions a 5-gallon bucket has the first defense of being limited to a sa'e batch. The second defense is
.the lack of available liquid sources. For 45-gallon barrels the first defense is the boron-i filled insert. The second defense is the lack of available liquid sources.
Analyses show that, for all the accident conditions in the Lube Blend Room, even at 7 wt.% water (or water-equiva!ent), an infinite single layer array of 5 gallon buckets each containing a safe batch at 5.0 wt.% enriched UO,-H O results in a maximum k,, of 2
approximately 0.78 which is adequately'suberitical. At 7 wt.% water (or water-equivalent),
an infinite single layer array of filled 45-gallon barrels results in a maximum k,, of j
approximately 0.89 which is adequately subcritical.
15.1.9.1.2 Radiation Protection t
The lube blending operations are performed in a limited access radiation contrelled area.
{
Personnel are required to wear protective clothing and eye protection while in the area._
i This area is operated at a pressure slightly below atmospheric to preclude egress of
. airborne contamination, and extensive use is made of enclosures around process l
equipment which contains readily dispersible uranium oxide and surface contamination l
such as the lubricant addition stations, and utility hoods, in the lube blend room air is sampled for radioactivity and evaluated on a frequency determined by historical l
experience.
. 15.1M.1.3 Fire Protection l
l The UO, building is rated as ncncombustible. Fire loading is kept to a minimum through l
monthly inspections. Fire extinguishers (dry chemical or CO ) a: arm pull boxes, and heat 2
detectors are strategically placed throughout the lube blend area. Where moderation control is in place, high expansion foam, dry chemical or CO are required to be used to i
2 combat a fire.
[
All flammable and combustible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
AldENDWENT APPLCATON DATE:
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PART ll-SAFETY DEMONSTRATION nev. ;
15.1.9.1.4 Environmental Safety i
Materials processed in the tube blend area are contained or confined in hoods ana/or containers. Liquid sources are external to the lube blend area, nevertheless the concrete floors are sealed to be liquid tight and contain no floor drains. The lube blend area is serviced by a "once-through" HVAC system that is continuously monitored for radioactive contamination. The exhaust systems for the pelletizing area, including the tube blend g room, are double HEPA filtered and have deluge systems to protect the final filters from fire.
l
- 15.1.9.2 Pellet Pressina in Room 100 there are four pellet presses and their associated equipment. The function of the equipment is to press UO powder into " green" (unsintered) pellets. The pe'lets are 2
conveyed in a line from the press table to the stacker where they are loaded into molybdenum boats for sintering.
The major system components are:
- 1) Pellet presses (including the oil sump, feed hopper and press table for each);
- 2) Powder queues; and
- 3) Vacuum filter.
15.1.9.2.1 Criticality Safety in the press area criticality safety is ma(ntained by fixed neutron absorbers, moderation control, enrichment control, favorable geometry, and mass control.
Pellet Presses (includino oil sumos. feed hoonerscand oress tables Criticality safety at the presses is maintained by enrichment control, moderation control, and slab thickness control (favorable geometry).
l Summarv of Accident Conditions The accident conditions in the presses involve saturating UO powder with water and 2
closely reflecting the mixture with water. Defenses against unacce.ptable k, in such instances include control of enrichment, multiple controls on moderator, and mass control based on the amount of UO in a barrel. The press oil sump is a safe slab.
2 AMENDVENT APPLCATON DATE:
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y SiemenS Power Corporation - Nuclear Division eur.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 701257 PART 11 - SAFETY DEMONSTRATION REv.
Powder Queues in the press area criticality safety in the powder barrels and buckets is maintained by fixed neutron absorbers, moderation control, mass control, and spacing.
Summary of Accident Conditions See Section 15.1.9.1.1 Vacuum Filters The vacuum filters are geometrically safe for 5% enriched UO.
2 15.1.9.2.2 Radiation Protection The pellet pressing activities are performed in a limited access radiation controlled area.
Personnel are required to wear protective clothing and eye protection while in the area.
This area is operated at a pressure slightly below atmospheric to preclude egress of airborne contamination, and extensive use is made of enclosures around process equipment which contains readily dispersible uranium oxide and surface contamination. In the pellet press area air is sampled for radioactivity and evaluated on a frequency determined by historical experience.
15.1.9.2.3 Fire Protection The UO building is rated as noncombustible. Fire loading is kept to a minimum through 2
monthly inspections. Fire extinguishers (dry chemical or CO ). alarm pull boxes, and heat 2
detectors are strategically placed thrcughout the pellet press area. Where moderation control is in place, high expansion foam, dry chemical or CO are required to be used to 2
combat a fire.
All flammable and combu'itible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
15.1.9.2.4 Environmental Safety Materials processed in the pellet pressing area are confined within containers, closed cones / transfer chutes, or ventilation hoods until they have been pressed into pallets. The concrete floors are sealed to be liquid tight and contain no floor drains. The pelletizing area in general is serviced by a "once-through" HVAC system that is continuously monitored for radioactive contamination. The exhaust systems for the pelletizing area are double HEPA filtered and have deluge systems to protect the final filters from fire.
PAGE NO :
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March 17,1997 15-33d 1
sPC-ND 3330 947 (R 107 921 l
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO 70-1257
. EMF 2 PART 11 -SAFETY DEMONSTRATION i
nsv. i 15.1.9.3 Slaterina There are four sintering furnaces and associated equipment in Room 100. Green pellets from the pellet presses are placed into molybdenum boats at the stacker. Boats of green pellets are subsequently trarisferred from the stacker either to the green boat storage racks and their associated conveyors or directly to the sintering fumaces.
! ' The boats of green pellets are transferred from the storage racks or. stacker to a conveyor l
leading to a sintering furnace. A single line of boats is transferred through the furnace which typically heats the pellets in a reducing atmosphere to high temperatures. During the time at high temperature, the green pellets sinter (densify).
The sintered pellet boats from the furnace may be transferred to the sintered boat storage racks and associated conveyors or they may be transferred direct;y to the grinder area.
The major system components are:
t
- 1) Sintering boats-l
- 2) Green pellet stacker; i
- 3) Green pellet boat storage racks;
- 4) Sintering furnaces; and -
- 5) Sintered pellet boat storage racks.
15.1.9.3.1 Criticality Safety Criticality safety in the sintering area is maintained by neutron absorbers and geometry control.
4 Sinterino Boats The neutron absorbing characteristics of the molybdenum boats and the depth of the l
boats maintain criticality safety.
Summary of Accident Conditions i
Accidental addition of water to boats is a credible event because liquid lines are overhead
' near the north wall of Room 100 and no fire fighting restrictions are applied to this area.
Flooded boats with full water reflectioni even overfilled by 0.5 inches are critically safe in infinite planar arrays, s
-I f AMENOMENT APPLCATON DATE:
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March 17,1997 15-33 e SPC-ND 3330 947 (Ra 07 92#
SiemenS Power Corporation - Nuclear Division sur.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 PART 11 - SAFETY DEMONSTRATION REv.
Green Pellet Stackers The analysis of the sintering boats, discussed above, also covers the green pellet
, stackers.
l l.
Green and Sintered Boat Storage Racks l Criticality safety of the sintering boats in the boat storage racks is maintained by the neutron absorbing molybdenum boats and by controlling the geometry (stab thickness) of pellets.
Summarv of Accident Conditions Full water moderation and reflection of the storage racks requires full room flooding and is not credible. If, however, flooding were to occur, it would neutronically de-couple the tiers of pellet boats. Overfilling boats in the storage racks is precluded by a gauge that will not allow overfilled boats into storage positions.
Spilling pellets in the sintering area is unlikely to result in criticality, even with flooding. The optimum water-to pellet volume (VM,) is approximately 2 and the VM, for a large number of spilled pellets into a confined area is less than 1.
Sinterino Furnaces The sintering furnaces are criticality safe for an infinite line of reflected boats. Flooding is not credible because of fumace temperature.
Summary of Accident Conditions There are no credible criticality accidents in the sintering furnaces.
15.1.9.3.2 Radiation Protection i
The sintering activities are performed in a limited access radiation controlled area.
Personnel are required to wear protective clothing and eye protection while in the area.
This area is operated at a pressure slightly below atmospheric to preclude egress of airborne contamination, and uranium oxide is not handled in readily dispersible (i.e. non-pelletized) for ns. In the sintering area air is sampled for radioactivity and evaluated on a frequency determined by historical experience.
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. AMENOVENT APPUCATON DATE:
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70
. EMF-2 PARTll SAFETY DEMONSTRATION REV.
i 15.1.9.3.3 Fire Protection The UO building is rated as noncombustible. Fire loading is kept to a minimum t 2
mor"hly inspections. Fire extinguishers (dry chemical or CO ), alarm pull boxes, and heat detectors are strategically placed throughout the sintering area. Where moderation contro 2
is in place, high expansion foam, dry chemical or CO are required to be used to combat
! fire.
2 All flammable and combustible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
An extensive hydrogen detection system is installed near all hydrogen atmosphere furnaces to detect any leak of hydrogen into the room. The propane feed lines used for hydrogen burnoff and the disassociated ammonia (DA) feed lines used for the hydrogen / nitrogen cover gas are protected by automatic bleed and feed shutoff valves the point the DA/ propane lines enter the building.
The hydrogen / nitrogen atmosphere sintering furnaces are protected by automatic cover gas in case of a problem with the atmospheric mixture, and pressure relief blast doors in case of an explosion within the furnace.
15.1.9.3.4 Environmental Safety Pellets processed in the sintering area are contained in boats, which in tum are processe through closed furnaces. The concrete floors are sealed to be liquid tight and contain no floor drains.
The sintering area is serviced by a "once-through" HVAC system that is continuously monitored for radioactive contamination.
The exhaust systems for the
. pelletizing area in general are double HEPA filtered and have deluge systems to protect the final filters from fire.
15.1.9.4 Pellet Grindina and Inspection l inspection stations. The two principal ope'ations in the pell i
and inspection. The pellets are sized by wet centerless grinding. Water supplied from aare gri recirculating pump reservoir is sprayed onto the pellets during grinding. This water and the ground-off uranium are then carried to a centrifuge where the uranium is collected in a centrifuge bowl in the form of sludge.
The water is retumed to the reservoir. The centrifuge bowl is periodically replaced and the sludge in the partially filled bowls is dried.
The major system components are:
. AWENDMENT APPUCATON DATE:
, P AGE NO -
March 17,1997 15-33 g SPc NO 3330 947 (A 107 9h
Siemens Power Corporation - Nuclear Division EMF 2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 0
REV.
PART 11 - SAFETY DEMONSTRATION
- 1) Pellet feed hoods;
- 2) Grinder lines;
- 3) Centrifuge and reservoir; and
- 4) Bowl cleanout / drying hood.
l 15.1.9.4.1 Criticality Safety l Criticality safety in the pellet grinding and inspection area is maintained by enrichment l control and geometry control.
Pettet Feed Hoods Criticality safety in the pellet feed hoods is maintained by contro!!ing enrichment and geometry (slab thickness).
Summarv of Accident Conditions The first accident condition is the case in which the pellet feed hopper is covered with The optimally moderated pellets at a depth that approaches a critical slab thickness.
newer belt-fed pellet hopper has a boat loading mechanism that sets the boats down before the pellets inside the boats are released. The first defense for this type of hopper is that the pellets begin at less than the inner height of a sintering boat (somewhat less than 3.6 inches) and become increasingly spread out. The second defense is the fact that the hood has no water sources.
The older vibratory pellet hopper differs in that boats of pellets are dumped onto the hopper as the boat is tipped over. For this reason, it is possible that the pellets will form an initial mound that may exceed the 3.6 inch limit for the hopper. The first defense is that this potential peak in the mound of pellets is transitory in that the pellets immediately begin to spread out; also, no muhanism exists for the pellet height to increase. The second defense is again the fact that the hood has no water sources.
The second accident condition considered was the condition in which the pellet bowl becomes filled past the top of the bowl with optimally moderated pellets. The first defense is the fact that pellets will spill out of the bowl before the bowl fills completely. The second defense is again the fact that the hood has no water sources.
The third accident condition considered was the condition in which a spill of pellets on the floor of the hood approaches the critical slab thickness of 4.2 inches and becomes The first defense is that pellets are cleaned out of the hood optimally moderated.
whenever any significant quantity accumulates. The second defense is the fact that no PAGE NO :
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1 Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET eur.2 i
PART 11 - SAFETY DEMONSTRATION asy.
i water source is available. In addition, the V,/V,for randomly spilled pellets is less than 1 where the optimum value is 2.
Grinder / Inspection Lines Criticality safety at the grinder lines, including pans to catch pellets that fall off the l i
buckets for reject pellets and the pellet tray loading platform, is maintained by ge (slab thickness) and mass control.
Summary of Accident Conditions The first accident condition identified for the grinder inspection line is that the pellet line spills pellets into the hoods surrounding the first few sections of the line. The second is that a safe batch is exceeded in any of the reject buckets. The third is that a spacing violation occurs with the reject buckets. All of these conditions are conservatively bounded by the models used in sensitivity studies and produced acceptable results.
Centrifuoe and Reservoir Criticality safety for the centrifuges and reservoirs is maintained by geometry control.
Summary of Accident Conditions The only criticality concem for the centrifuge occurs if significant quantities of sludge exist in the centrifuge housing external to the bowl. This is not credible, because any material that escapes the centrifuge bowl goes to the reservoir.
One credible accident condition regarding tha reservoir is that the centrifuge is run without a bowl being present. In this case, sludge would go directly to the reservoir. For this reason, an overflow port has been installed to prevent the solution height from exceeding a safe depth of eight inches.
Bowl Cleanout /Drvina Hood Criticality safety is maintained by enrichment control and geometry control.
i l
Summary of Accident Conditions The centrifuge bowls, containing either wet or dry sludge and the bowl cleanout station, drying ovens, and scrap buckets were modeled conservatively. The centrifuge bowl cleaning station had one bowl between the two drying ovens, each of which contained three bowls. The k, of the system, completely reflected, was less than 0.88. K,, of an AMENDMENT APPLCAff0N DATE.
. NE W March 17,1997 i
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SPC.ND 3330 947 tR 79h
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SiemenS Power Corporation - Nuclear Division eur.2
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SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM 1227, NRC DOCKET NO. 701257 Q
PART ll - SAFETY DEMONSTRATION nev.
4 overbatched, flooded bucket added in close proximity under the station is the same
. whether or not it is near the station.
lj 15.1.9.4.2 Radiation Protection l
l The pellet grinding and inspection process is performed in a limited access radiation controlled area. Personnel are required to wear protective clothing and eye protection l while in the area. This area is operated at a pressure slightly below atmosphere to i
preclude egress of airborne contamination, and extensive use is made of enclosures and hooding around any process equipment which contains readily dispersible uranium oxide and surface contamination such as the grinding stations. In the pellet grinding and inspection area air is samp'ed for radioactivity and evaluated on a frequency determined by historical experience.
15.1.9.4.3 Fire Protection The UO building is rated as noncombustible. Fire loading is kept to a minimum through 2
monthly inspections. Fire extinguishers (dry chemical or CO ), alarm pull boxes, and heat 2
detectors are strategically placed throughout pellet grinding and inspection area. Where moderation control is in place, high expansion foam, dry chemical or CO are required to 2
be used to combat a fire.
All flammable and combustible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
15.1.9.4.4 Environmental Safety Materials processing in the pellet grinding and inspection area are contained or confined in hoods. The concrete floors are sealed to be liquid tight and contain no floor drains. The pellet grinding and inspection area is serviced by a once-through" HVAC system that is continuously monitored for radioactive contamination. The exhaust systems for the pelletizing area in general are double HEPA filtered and have deluge systems to protect the final filters from fire.
15.1.9.5 Pellet Storane Area As UO pellets come off the grinder inspection line they are placed onto metal or plastic 2
trays. The metal trays are either " outgas trays" or trays for the inner container for the RBU pellet shipping container. The plastic trays are placed into inner containers for the ANF-250 shipping container. Outgas trays are stacked ten trays high and stored on metal pallets. Three outgas tray stacks may be placed on each pallet. RBU inner containers (P-
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-sur-2' PART 11 - SAFETY DEMONSTRATION
' REV. i boxes) are placed on a special sub base and stored two per pallet. ANF-250 inner containers (K-boxes) are stored three per pallet.
The major components in the pellet storage area, located in the south end of Room 100, are:
1
- 1) Pellet Storage Racks;
- 2) Pellet Outgas Tray; I
- 3) RBU Inner Container (P-box);
- 4) ANF-250 inner Container (K-box);
- 5) Pallet Make-up Tables; and
- 6) Conveyors.
15.1.9.5.1 Criticality Safety The Pellet Storage Area is dependent upon controls on tray stacks to assure criticality safety. Spacing between tray stacks is required if the stacks are higher than the generic-safe slab thickness of 3.6 inches and not required at 3.6 inches or less. Enrichment and the degree of moderation are also controlled.
Pe!!et Outcas Travs Pellets to be outgassed and loaded into rods are typically placed onto outgas trays after pellet inspection. These trays may be placed into stacks up to 10 trays high. Tray stacks are placed onto 28" x 32" steel pallets for storage in the racks at the south end of Room 100. Criticality safety for outgas trays is maintained by controlling the height of the stacks, maintaining this geometry both inside and outside of the storage racks; maintaining spacing between stacks; controlling enrichment to a maximum of 5 wt.% ssU; and controlling moderators inside the rack, t
Summary of Accident Conditions
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- ' Trays were conservatively modeled with less steel than is actually present; with up to 0.5 inch diameter pellets (0.471 inch diameter is largest that can be loaded onto stacked l trays); moderated with 10% water (a conservative upper bound); and fully reflected.
For infinite rows of end-to-end tray stacks 10 trays high, as could be found on conveyors, the peak k, was slightly over 0.80.
For pellet tray stacks on pallets, with an infinite array of pallets with three stacks of trays per pallet, as could be found on the pallet make-up tables and in storage racks, and taking no credit for the steel in the pallets, k, was slightly below 0.87.
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Siemens Power Corporation - Nuclear Division EMF 2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 PART 11 - SAFETY DEMONSTRATION REv. I Pellet Storaae Racks e
There are four pellet storage racks, each designed to hold a 9x9 array of pallets of pellets.
In order to be stored in the racks, pellets must be on a pallet. The pallet may hold pellets in outgas tray stacks limited to 10 trays high, in K-boxes, or in P-boxes. The pallets that these various pellet containers sit on are mechanically designed to maintain 2.75 inch separation among the allowed three stacks of outgas trays or thrre K-boxes ad 4.25 inches between the two allowed P boxes. The accident conditions discussed beiow are i
for pellets on trays on pallets in the storage racks.
t Summary of Accident Conditions Accident conditions for the storage rack assumed a highly conservative interspersed moderation (10% water volume), full racks, overstacked trays, plus interaction with two in-transit pallets.
With optimum moderation within and between pellet stacks and the most reactive pellet diameter (0.471 inches), k, is slightly greater than 0.95, but less tha'1 the 0.97 accident limit. Partial tray loadings are less reactive than full tray loadings.
Violation of the 10 tray limit on stack height was evaluated and a stack height of 15 results
+
' in a k, slightly less than 0.95.
1 At certain levels of interspersed moderation within the tray stacks, as well as certain levels between the tray stacks, values of k, become unacceptable. The question of what credible upper bound can be assumed for moisture levels was addressed by performing a test where an outgas tray, loaded with steel pellets, was sprayed with water to determine the maximum amount of water that could accumulate on the pellets before running off.
This test concluded that for a stack of 10 loaded outgas trays, 350 grams of water is the maximum amount of water the stack could hold. A stack of outgas trays, fully loaded with
' maximum diameter pellets, has a total void space of over twelve liters. If 700 grams of
- water (double that found to be possible) is placed in this void space, the volume percent moderator in the tray stack is about five percent. The 10 volume percent used in the calculations is conservatively four times the amount believed to be possible.
RBU Inner Shiopino Container (P-box)
Pellets may also be placed onto P-box trays after pellet inspection. These trays may be placed into stacks up to 18.2 cm high. Tray stacks are placed into the stainless steel P-box which has inner dimensions 34.7 cm wide by 31.5 cm long by 21.1 cm high. P-boxes are placed onto a steel "sub-base" which fits over the 2.75" wide spacer bars on the steel AMENDMENT APPUCATON DATE:
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 7
, s u p.a PART 11 - SAFETY DEMONSTRATION
' REV.
pallets. This arrangement provides a minimum spacing between the P-boxes of at least 4.25 inches edge-to-edge. Two P-boxes are allowed per pallet. These P-box pallets i
be stored in specified locations in the racks at the south end of Room 100.
Summary of Accident Conditions i
The accident conditions evaluated included optimum moderation and reflection between l infinite array of pallets containing P-boxes.P-boxes, optimum moderatio l
Infinite planar arrays of P-box pallets were modeled with two P-boxes per pallet. The tra
- stacks were modeled as flooded but the volume between the tray stack and the inner box wall was void and the volume between boxes on the pallet was void, the most reactive moderator condition. Close-fitted full water reflection was above and below the array.
Moderated conditions inside the P-box are highly unlikely, if not incredible. The highest k,
for these conditions was less than 0.91. In order to maintain criticality safety of loaded P-boxes, water must be kept out of the boxes and the spacing between boxes maintained as if the boxes are on pallets.
I For full and partially full P-boxes in all storage rack positions at optimum conditions of moderation (i.e., pellets stacks optimally moderated, no water between pe!!et stacks and the container wall, and no water between containers), k,, is unacceptably high. The defense against such conditions is keeping water out of the P-boxes by ensuring that the boxes are closed when they contain pellets and administratively restricting P-box storage to 45 specific positions in the eastern storage rack.
ANF-250 inner Containers (K-box)
Pellets may also be placed onto K-box trays after pellet inspection. These plastic trays
! may be placed into stacks that will fit into the K-box. Three K-boxes are allowed per pallet i and K-box pallets may be stored in specified locations in the racks at the south end of
- Room 100.
l Summary of Accident Conditions i
i The accident conditions evaluated included overbatching the allowed UO contents and 2
the assumption of optimum moderation within the storage racks.
l Infinite planar arrays of K-boxes both on pallets and separate from pallets were modeled edge-to-edge with optimum moderation with a maximum k,, for the 65 Kg UO loading limit 2
of less than 0.91.
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i Siemens Power Corporation - Nuclear Division EMF-2
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SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM 1227, NRC DOCKET NO. 70-1257 e
l i-PART li-SAFETY DEMONSTRATION -
REv. I I
I
. For full K-boxes in storage racks, each box was modeled containing 70 Kg UO pellets of i j
]
2 various diameters and 5 kg of water, which is more than 10 times the water equivalent of plastic trays. With optimum moderation between K-boxes (approximately 3 vol % water) the peak k., was 0.9515.
1 The k., of K-boxes in the storage rack array, optimally moderated and overbatched, remains below 0.97.
15.1.9.5.2 Radiation Protection i
Pellet storage is performed in a limited access radiation controlled area. Personnel are required to wear protective clothing and eye protection while in the area. This area is operated at a pressure slightly below atmospheric to preclude egress of airborne contamination, and extensive use is made of inner shipping containers for pellets which
)
will be shipped.
Sintered, ground and washed pellets do not pose problems with generating airborne contamination.
i
, 15.1.9.5.3 Fire Protection The UO building is rated as noncombustible. Fire loading is kept to a minimum through 2
monthly inspections. Fire extinguishers (dry chemical or CO ), alarm pull boxes, and heat 2
1 detectors are strategically' placed throughout the lube blend area. Where moderation controlis in place, high expansion foam, dry chemical or CO are required to be used to l
2 combat a fire.
l All flammable and combustible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
4 15.1.9.5.4 Environmental Safety
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The concrete floors are sealed to be liquid tight and contain no floor drains. Room 100 ic
- serviced by a "once through" HVAC system that is continuously monitored for radioactive l deluge systems to protect the final filters from fire.
contamination. The exhaust systems for Room 100 are double HEPA filtered and have i
i 15.1.9.6 Pellet Outaassina The pellet outgas process consists of two side-by-side outgas fumaces. Each of the r
fumaces is fed by a single wide conveyor assembly which transfers pellet tray stacks to the fumaces. Pellet tray stacks are transferred through the system end-to-end. From the exit of the fumaces a single tray stack cart transfers the stacks to either pellet storage AMENDMENT APPLCATON DATE:
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Siemens Power Corporation - Nuclear Division SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257
.eup.2-PART ll-SAFETY DEMONSTRATION REV.
units or directly to the rod loaders. This cart can transfer three stacks side-by-side. A second transfer cart handles single stacks and transfers the stacks from either of the storage units to the automated rod loading unit.
There are two stack storage units for outgassed pellets. The east unit is six compartments high by eleven compartments wide.
i l compartments wide. All this equipment is in Room 182.The west unit is five compartme j
1 The major components in the pellet outgassing system are:
l
- 1) Pellet outgas conveyors and furnaces;
- 2) Pellet outgas storage racks; and
- 3) Pellet outgas transfer carts.
15.1.9.6.1 Criticality Safety Criticality safety in the pellet outgas process relies on enrichment control arsd on both administrative and engineered geometry control; i.e., limiting tray stacks to 10 hign and requiring only end-to-end tray stacks on conveyors and in furnaces (administrative) and limiting conveyor and furnace width such that only end-to-end stacks will fit (engineered).
i Moderation control is exercised to the extent that equipment must be free draining such l
that interstitial water shall not accumulate in the trays. In addition the neutron absorbing characteristics of the steelin the outgas trays is relied upon.
Pellet Outcas Conveyor and Furnaces Criticality safety requires trays of pellets be stacked no more than 10 trays high and that rows of these pellet tray stacks on the conveyors and in the furnace be end-to-end and a single tray wide. In addition the trays must be free draining and built to a specification requiring at least 2.5 kg of steel.
Summary of Accident Conditions i
Various sensitivity studies determined that the most reactive tray stacks were those with large pellets (0.5 in.) only in odd numbered rows on the trays. Trays in this configuration were double stacked (20 trays high) and with optimum moderation and full water reflection k, was slightly greater than 0.90. Violation of spacing; i e., two infinite end-to-end rows with no spacing between rows, and optimum moderation and full water reflection resulted in k, under 0.90. Finally, violation of the end-to-end tray stack requirement; i.e., an infinite row of side-by-side tray stacks optimally moderated and fully reflected resulted in kg slightly greater than 0.94.
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Siemens Power Corporation - Nuclear Division eup.2 SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 e.
PART 11 - SAFETY DEMONSTRATION
' nev. l l
Pellet Outaas Storaae Racks e
i Criticality safety in the pellet outgas storage racks depends upon control.of onrichment l (s5%), geometry (s10 pellet trays per stack), and design of the pellet trays (22.5 kg steel i
for neutron absorption and free draining to prevent moderator accumulation).
Summary of Accident Condition _.g I, A large storage rack (six storage compartments high by eleven compadments wide) was l
modeled. For typical pellets (s0.4 inch diameter) where all rows in the pellet trays are loaded, overstacking (13 trays per stack-the most that can physically fit in a storage compartment) with optimum moderation and full reflection results in k, of 0.943. Trays of large pellets - (0.5 inch diameter) with. pellets only in odd rows, the two center
- compartments overstacked with 13 trays per stack, optimally moderated and fully reflected
. yields a k, of 0.935.
t Pellet Outaas Transfer Carts e
Criticality safety on the outgas carts relies on enrichment control (s5%), tray stack height (s10), limiting the number of tray stacks per cart (s3 on the cart transferring pellets to j
. storage and 1 on the cart transferring pellets to rod loading) and the design of the trays j
j (self draining and 2 2.5 kg steel).
l Summary of Accident Conditions With the transfer cart overstacked to 13 trays per stack 'vith large pellets in odd rows, the cart immediately adjacent to the middle of the fully loaded larger storage rack, and full water moderation and reflection - the most reactive condition - the k,is slightly less than O.97.
l 15.1.9.6.2 Radiation Protection 1
i i Pellet outgas and storage is performed in a low surface contamination controlled area.
This area is operated at a pressure slightly below atmospheric to preclude egress of airborne contamination. Sintered, ground and washed pellets do not pose problems with generating airbome contamination.
15.1.9.6.3 Fire Protection The UO, building is rated as noncombustible. Fire loading is kept to a minimum through monthly inspections. Fire extinguishers (dry chemical or CO ), alarm pull boxes, and heat 2
detectors are strategically placed throughout the pellet outgas and storage area. Where
. AMENDUENT APPLCATCN DATE:
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Siemens Power Corporation - Nuclear Division
- E M F-2*
SPECIAL NUCLEAR MATERIAL LICENSE NO. SNM-1227, NRC DOCKET NO. 70-1257 l
PART ll-SAFETY DEMONSTRATION nev j i
i moderation control is in place, high expansion foam, dry chemical or CO are required to i
l 2
be used to combat a fire.
l All flammable and combustible liquids of greater than one pint in volume used in the process are stored in fire rated containers.
15.1.9.6.4 Environmental Safety
- The concrete floors are sealed to be liquid tight and contain no floor drains. Room 182 is serviced by a "once through" HVAC system that is continuously monitored for radioactive i
i contamination. The exhaust systems for Room 182 are double HEPA filtered and have deluge systems to protect the final filters from fire.
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l I
l AMENDMENT APPLCATION DATE:
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March 17,1997 15-334 sPC-ND 3330 947 (R-107 92)