ML19261C780
| ML19261C780 | |
| Person / Time | |
|---|---|
| Site: | 07106357 |
| Issue date: | 09/08/1970 |
| From: | Griffin W BABCOCK & WILCOX CO. |
| To: | Nussbaumer D NRC COMMISSION (OCM) |
| References | |
| NUDOCS 7904020162 | |
| Download: ML19261C780 (16) | |
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Regulatory my CabCOCk & WilCOX uere P. O. Box 785, L ync hburg, Va. 24505 Tekthone- (703) 38?5111 b
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U. S. Atomic Energy Comma sion NF I. O E7[..
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3' Division of Materials I,icensing i,
e Uashington, D. C.
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Attention:
Mr. D. A. Nussbaumer, Chief I
Fuel Fabrication and Transportation Eranch
Subject:
SN:1-42, Amendment Of, For Shipment of Special Nuclear Material Centlemen:
The specification shipping containers available for transporting fissile radioactive material with relatively high H/X ratios are some-what 1imited.
This limitation produces a handicap for B6U as the need arises to transport large quantities of fissile radioactive material in a single shipment.
The provisions of 10 CFR 71.5 and 71.6 are th~ only authorized means available to B6U for shipping fissile radioactive mate-rial with H/X ratios in excess of 3, other than our NFP-55 package, which is restricted to an H/X ratio of 20.
The mass restrictions in-posed under provisions of 10 CFR 71.5 and 71.6 are too restrictive vl'en a large quantity of fissile radioactive material needs to be transported as a single shipment.
We are proposing that a license amendment be issued to B&U authoriz-ing preparation of fissile radioactive material for shipment in our NNFD-10 package, each package restricted to 350 grams U-235 with no restriction on the H/X ratio of material contents. This package and its contents are described and evaluated according to criteria of 10 CFR 71 and is enclosed as an attachment to t.his letter.
E6W respectfully requests D:!L review as soon as feasible.
B&W needs D11L approval as soon as possible to facilitatx shipment of metallographic mounts to fulfill contract requirements, if any questions arise, please O!
call us, f,
N Very truly yours, Q
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BAUCOCK & UILCOX n,
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W. E. Gri f fin N R4 9
WEC/bca Nuclear Materials Control Nr G
Attachment Licensing g jV4 7904020 S'd 0
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SilIPPliiG C0:lTAlllER, MODEL fil1FD-10 Babcock & Wilcox Septembct 8, 1970
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SIIIPPING CONTAT!;ER, MODEL N::FD-10 A 55-gallon container, DOT Specification 6:1 package equipped with a modified 2R Specification inner container has been evaluated for the shipment of normal form fissile radioactive material.
The modification of the DOT Specification 2R inner containment con-sists of waiving the leak-tight requirement in addition to waiver of the requirenent that the con *_ents of the inner container be contained in a polyethylene bottle or metal can.
The above requested deviations and subsequer.t imposed restrictions on the container contents have been evaluated for nuclear safety using the Density Analog method.
The nuclear safety analysis is included as Appendix A to this application.
The Model ' MFD-10 shipping container will be registered with the Department of Transportation.
Evaluation of the shipping container has been made in accordance with applicable regulations of 10 CFR 71.
71.22 PACKAGE DESCRIPTION (a)(1)
Gross Weight - Maximum 350 lbs.
(2)
!!odel NNFD-10 (3)
The outer package is constructed to meet requirements of a D0f Specification 6M package.
(i) The containnent vessel shall be a modified DOT Specification 2R inner container. This inner container meets all specifications of a 2R inner container with the exception of being a leak tight container.
It is requested that this requirement be waived as the nuclear safety analysis assumes optimum internal moderation and reflection. There will be no outleakage of radioactive material due to composition of contents.
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(ii) There are no materials within the package that are used specifically as neutrop absorbers or moderators.
(iii) The containe.ent vessel is supported within the outer package by rings of solid industrial cane fiberboard (Celotex).
(iv) Not applicabic (v) Not applicable (4)
Not applicable (b)
PACKAGE CONTENTS (1) Material contents in package shall be unirradiated uranium metal, alloys and/or compounds in normal form at any enrichment in the U-235 isotope.
(2) Maxitaum 350 grams U-235/ package with no restriction on the H/X ratio of package contents.
(3)
Uranium metal, alloys of uranium, metallographic mounts encased in bakelite.
(4) Optimum conditions of moderation and reflection were assumed for the package.
(5) Maximum weight of contents - 100 lbs.
((-)
Not applicable 71.23 PACKAGE EVALUATION (a)
See Subpart C Standards (b)
Fissile Class II - Minimum transport index of 1.3 to be assigned to each individual package.
(c)
Fissile Class III - Maxitaum 38 packages per shipment.
No special controls for transport other than nor:aal transpc rt handling.
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In the event of an accident or signif icant delay in shipment, The liabcock 6 WIleux Co. is t o be notIfled immediately.
71.24 PRoci:Dt!R AI, CONTROI.S Prior to the first une of each pachar,e on or afttr date of this, application, the packap,e will be in::pect ed t o ar < ure compliance with the requ i remen t :, specified in t h i s.
application.
The in-upector wJll innure that the packap,e if IdentIfled with proper Jabeling, and marking,s.
If a packap,e I r.
detected by vinual examination to have deteriorated to the point that it doer, not meet packar,e specificationn, it will be repaired or re placed :o an to rentore the package to I t c, required conditinna.
SUliPART C - PACRAGE ';TANDARDS 71.31 GENERAI. STANDARDS FOR PACEAGING (a)
There are no materials used in the fabrication of the package or contente, which will cauac any chemical re-action.
(b)
The outer package clonore shall be accompiinhed by a 12 gage t>ol t -lock ing ring with d rop f orged J up,s, one S/8 inch bolt and of which ir, threaded to receive a lock nut.
(c)
No lifts will be required during, shipment.
(d)
No tie-down devicer, required during shipment.
7].32 STRUCTUR AI, STANDAisDS (a)(b)
Package is constructed according, to DOT Specification 6M package with noted exceptions in applfration.
71.33 CRITICAL.ITY STANDA1:DS FOR FISSILE MATERI Al, PACK AGES (a)
The inner container in constructed according to DOT Specification 2R requirementr, with the exception of being leak-tight.
The inner container shall be re-ntricted to a maximum 3'30 g ramn U-235 with no rentric-tion on the ll/X rat 10 of contents.
If water leak, into e
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f the inner cont ainer and moderat ion occurs to the most reactive credible extent and the containment ver,sel is reflect ed on all sides by water, the contentr, will be subcritical. A mas, of 350 grams ti-235 is 1afe in any geometry by reference to Finure 1, TID 7016, Itev. 1, irrespective of the ll/X rat 10 of the material.
An additional safety anuurance exists in that the con-t a i n.ien t ve: nel ir a afe geome t ry 5.0" 1.D.
cylinder which is <,afe f or a 350 g ram 11-235 nas<. by reference to Figure 3, Tf D 7016,1:ev. 1.
(b)
Cont ent r. of thir packar,e wi11 not include 1Iquidr.
71.34 1: val.UATIO:10F A S1!;Gl.E PACKAGE A single !!odel NNI D-10 pachane, which is, constructed accord'ng to DOT 6:1 S'.ecificatlonn, meetr the requirementn for normal I
transport conditfonn er, well as the hypothetical accident con-ditionn. The !!OT 6M Speci f i cat ion pachage in an approved con-tatuer for the above trannport conditions by virtue of previous analyses and teatr,.
71.35 S'I ANDARDS FOR NOR'!AI. CONDITIONS OF titan", PORT Fol: SINCI.E PACKAGE (a)(1)
The inner :entainer it, constructed accordiny, to a DOT 21! Specification container. We request that the re-quirement for a Jenk-tight container be waived at there will be no re1 cane of radioactive material from the con-tainer due to form of fiscile material authorized for this package.
(2)
The outer package is the equivalent-of a DOT 6?! Specifi-cation package which satinfactorily fulfills conditionn relevant to nornal transport.
(3)(4)(S)
Not applicable (b)(1)
An individual package wf11 be subcritical (reference 71.33(a)).
(2)
The geometric form of the package contents are not snb-r,tantially altered an verified by tents on a DOT 6M p a c ha f,2.
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e (3)
The possibility of in]eahage of water into the contain-ment vessel exist:,, however, the most reactive condi-tion har been assumed in the criticality evaluation.
(4)
Nonaal t rannport condit ions do not af fect the nuclear safety of the package contents.
(c)
Not applicable 71.36 STANDARDS FOR In'PO'IIIETI CAL ACCI DENT CONDITI ONE FOR A SINGLE PACKAGE (a)
Not applicable (h)(1)
The contents are in the most reactive configuration.
(2)
Optimum moderation has been assumed.
(3)
Optimum reflectance has been assumed.
7'.37 EVALUATION OF AN ARRAY OF PACKAGES OF FISSILE MATERI AL Reference Appendix A to this application.
71.38 Not applicabic 71.39 SPECIFIC STANDARDS FOR A FISSILF CLASS II PACRAGE Reference Appendix A to this application.
71.40 SPECIFIC STANDARDS FOR A FISSILE CLASS III SHIPMENT Reference Appendix A to this application.
The nuclear safety analysis prt'sented in Appendix A, page 3, shows the allowabic number of packages per shipment for Fissile Class II under normal and accident conditions in relation to the U-235 nass per package.
This analysis was ext ended by a calculation on page 7 to Appendix A to show that two identical shipments in contact with one another would be suberitical under accident conditions.
Sinc ( the type of materials that will be auth';rf. zed for the NNFD-10 package will constitute fissile radioactive materials containIng not s
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more than Type ~A quantities of radionuclides, t he N::FD-10 package in exempt from the hypothetical accident r equirenen t :,.
Yet, this package doen meet the hypothetical accident conditions.
Thir, package meets the ntandards for norual conditions of transport' therefore, we request that the NNFD-]O package he subject to Type A quant i ty rest rictions and normal transpurt conditionn.
I:ormal transport condi tions f or f ir. :511e Cl ar;<. 11 restrict each package to a minimum transport index of 1.3 and a maxiuum 38 packanen per shipment for fi: nIIe Class III.
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f APPEi: DIX A Sabcock & h'itcox September 8, 1970
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NUCLI:AR SAFEIY OF GM CO'Tl All;LR UHE:' USED FOR Sli!PPING !!ETALLoditAPilIC MOU::TS P rob l ejn :
Juntify the nuclear safety for shipping nietallographic mounts in the standard DOT 6M container and deteruine the number that may he shipped an a Cl a r-: s II nhlpment.
Assumptionn made to simplill the problem:
The problem is simplified by rentating the problem ao follows:
De t e rm i ne the number of 6M cont ainers which may be shipped an a clas, 11 shipment when containing either 350 gramn or 300 grams of fully enriched uranium without any ll/X (11/1?-235) re-striction.
All space within the Juner container is ansumed occupied by either U-235 or water.
Conclusionn:
1.
Twenty-four (24) 6:1 containern may be shipped t thout any II/X rentrict ion if each container in limited to 350 grams of U--2 35.
2.
Thirty-too (32) 6M containers may he nhipped without any P/X restriction if each container in Ifmited tc 300 gramn of U-235.
3.
This analynin does not permit the prenence of " super-moderatorn" nuch as polyethylene.
Bakelite, in which the fuel specimenn are mounted, han les, than half the hydrogen dennity of water (about the same a:nount of carbon an hydro-gen) and 13 not censidered a supermoderat or ; Hakelite is therefore pe rm i t t e d.
Sr cifications:
DOT 6:1 container a.
Outside container:
55 gallon drum 32 inches high 22.5 faches in diameter Walls of schedule 16 nteel a
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Inner container:
Safe geometry pipe 5.0 inch ID 22-3 /8 inch high Pipe is centered in drum with at 1 cast 4 inch clearance top and bcitom Schedule 4 0 steel walls - 1/4 inch thick Space between inner container and drum is filled with c.
celotex, a type of fiberbor.rd insulation.
d.
Assumed accident dimensions Inner container is not affected Outside container is compressed to a 20.0 inch diameter, height is not affected. In spe cting pictures of drop tet. performed on the DOW Modei 1518 contaiacr (prototype for the 6M containcr) indica:cs this to be a conservative assumption.
Justification of Nuclear Saftty:
Nuclear safety ht s be.cn justified using the Density Analog Method. The Cask Designers Guide (ORNI.-NSIC-68) quoting C. L. Brown, Senior Nuclear Safety Specialists at Pacific Northveut Laboratory, states that this method is recommended as the most applicable one for transportation problems.
C. L. Brown in SC-DC-67-1305 states this method is based or. one of the few well-foundef principles in criticality safety - the density scaling Ir.w.
Both Brown and the Cask Designers Guide state that this method is well verhied with experimental results; for solutions in cylinders the method is conservative.
H. C. Pa eton and D. R. Smith of Los Alamos have both recommended use of this method.
Calculations have been made against optimum moderation to rer ove any restriction on H/X within the shipping container. In other words, the fraction critica'.
ratio um the minimum (with respect to concentration) critical mass and the minimum (with resi.ect to concentration) bare spherical critical mass was used in the scaling equation.
The safety of individual containers is doubly assured both by a safe mass (350 grams) and by safe geometry (5 inch ID pipc).
Results of the Density Analog Calculations are given in Tabic 1:
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Table 1 Permissible Number of 6M Containern as Class II Shinment Grams of U-235 Per Container Condition 300 350 Normal 52 38 Accident 32 24 It may be' observed that the accident condition is the limiting condition.
Under normal conditions array reflection is not considered and the predicted critical number is divided by 5; under accident condition array reflection is considered and tbc predicteu c ritical number is cUvided by 2.
Interspersed moderation is assumed under all conditions because of the presence of celotex.
Tynical Calculatio;.
(for 350 grams per container)
The basic equations of the Density Analog Method are as follows:
Mc (reflected) > Mso (bare)
' S g
RM P
(1) i ol
[The scaling equation]
whe re: _
Me (reficcted) = minimum water moderated and water reflected critical mass Mso (bare)
= minimum critical mass of bare sphere at density in container (assumed at optimum moderation)
R
= factor for array reflection (approximate ratio between bare and reflected critical masses)
M
= factor for interspersed moderation p
= ratio of effectiva density of fissile material
[
in array to density of fissile materialin container o
S
= 2 (1 -f) f = fraction critical = ratio of the effective bare mass of a unit to the bare critical mass of the same fissile material in a similar shape
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1 Nc (reflected)
Me (reflected)
=
M actual whe r e:
Nc (reflected) minimum water moderated and reflected
=
critical number of units in array M actual actual mass of an individual unit
=
Mso (bare) 1.45 Kg U-235 (re: TID-7028)
=
Accordin;, to tne U. K. Handbook,.this value is 1.6 Kg U-?.35; therefore, the 1.45 value should be conser vative R = 2.7 (re: Article by Brown in SC-DC-67-1305)
Brown gives a value of 2.7 at an H/X of 400 (93 w/o enr.) and 2.0 at an H/X of 5 00 W.9 w/o enr.). Since optimum moderation occurs at an H/X of about 5 00, 2.7 should be a conse rvative value.
M = 1.12 (re: Article by Brown in SC-DC-67-1305)
Brown gives a value of 1.26 at an H/X of 200, 1.12 at an H/X of 500, and 1.08 at an H/X of 800 1.12 is therefore a reasonabli.
value.
F/p
=
0.07968 for the normal condition 0
0.10085 for the accident condition
=
p is the effective density in the array or
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, where p is density in
=
p V
0 container array um,c V
F
_=
p V
o array unit Ve = cffective volume of container or actual volume plus reflector savings volume.
Drum space is occupied by celetex. Adcock and McCarthy, in a paper given at the Second Symposium on Paci:ing and Transportation of Radioactive Material, state that celotex in the DOW 1518 container was experimentally
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t determined to be equivalent to one inch of wate r. T his being true, celotex in the 6M container is equivalent to about 2 inches of w ate r. According to ARH 600, this yields a reficcior savings of about 3.2 cm.
Dimensions of inside container-I. R. = 2.5 inches = 6. 35 cm height = 22.375 inches - 56.8 cm 7
V e = (5 6. 8 3.2 + 3.2) (H)(6. 35 + 3.2)~
3 15,298 cm
=
It is assumed that the drums will be in a close packed triangular array,.i.e.
E,e 22 5 inches normal = d (2 0. 0 inche s accident)
.. Varray unit = (height)(Au) 2 Au = 2 ( d;- J~5 ), d = diameter height = 32 inches 3
Varray unit (normal) = 22 9, 681 cm (accident) = 181,438 cm3 is/p (Normal) =
1S,298 = 0.07968 0
229,681 p/p (Accident) =
18,2 98 = 0.10085 0
181,438 S = 2(1 - f% f = fraction critical
= 1.5616
= bare mass of sm.gle unit critical bare mass in sam shape bare mass = p V e O
p
= 35 0 / Volume of container
= 0.04864 gm/cc 0
.. bare mass = (0.04864) (18,298) 890 grams
=
Critical bare mass in same shape
= Moo (bare)(shape factor)
The shape factor may be determined by either using the equality of Buchlings between a cylinder and a sphere or
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i from a curve of shapc factd'r Ve,rtur thei n
Height to Diameter ratio (H/D)
H/D ratio = 22.375 'in = 4.475 5 in From Fig.17 (TID-7016) the shape factor is about 2.S at an H/D of 4.475. This was also checked using buckling equality betweca a critical sphere and cylinder.
. '. bare critical mass in same shape
= (1. 45 ) (2. 8) = 4. 06 Kg.
.~. f = 8 9 0 = 0.2192 4060
. ~. S = 2 (1
. 2192 ) = 1. 5 616 Under normal conditions, array
- ficction is not considered; therefore, 0.07968 -1*5616 I
Mc = 1,45 0 l
1.12
= 67,288 grams = predicted critical Nc = 6 7, 2 8 8 = 192 = critical number 350 Clas.s II type shipments require that the number of containers per shipment be limited to 1/5 this number or 192 = 38 = permitted number 5
Under accident conditions, array reflection is considered; therefore, Mc (refl.) = 1,45 0 (0.10085) - ~ 5616 1
(2. 7)(1.12 )
= 17,242.8 grams Nc (refl.) = 17,242S = 49 350 6
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Page 7 Class II shipments require that the critical number under accident condi-tions be divided by 2 or 495- = 24 = permitted number this is the limiting number for 350 grans per contciner, 2870