ML19270G012
| ML19270G012 | |
| Person / Time | |
|---|---|
| Site: | 07106206 |
| Issue date: | 03/21/1979 |
| From: | Zeff P BABCOCK & WILCOX CO. |
| To: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 12340, NUDOCS 7904090377 | |
| Download: ML19270G012 (15) | |
Text
.
3 s
@C PUBtjc 00ggMENT 80 BSbCOCk&Wi!COX row ceneranon cmuo
___A-P.O. Ocx 12CO. Lynchburg. Va. 24505
>{3 Te!cphone: (804) 334 5111 March 21, 1979 Mr. C. F. MacDonald, Chief Transportation Branch Division of Fuel Cycle T. Material Safety United States Nuclear Regulutory Commission Washington, D. C.
20555 IWFERIINCIIS:
(1) Certificate of Compliance, USA /6206/AF, Babcock and Wilcox, "Model B" (2) BriW Applications Dated 1/16/70, As Supplemented 3/3/70 and 11/25/74 Gentlemcn:
As discussed previously with Mr. Odegaarten of your staff on March b, 1979, the Babcock f, hilcox Company, Commercial Nuclear Fuci Plant is submitting the following attachments regarding design changes on the flodel B fresh fuel shipping container for your review; This submittal replaecs the subnittal dated April 3, 1973.
The enclosed attachments to this letter describe the design changes on the containers, the safety analyses performed, and a set of drawings showing the safety related components of the shipping container.
The following is a list of the attachments submitted with this letter:
1.
Design Change 81; deals uith the Top End Gate of the Strong-back Assembly.
2.
Design Change #2; concerns the method used to secure the St rongback Asse:r.bly to the Shock Mount Frame.
3.
Design Change #3; involves a change in the hardware used
/
to secure the Fuel Assembly Baw Clamps to the Strongback Assembly.
4.
Design Change d4; is the change made to the Fuel Assembly lloid Down Pads and associated hardware and additional in-strument view ports.
8 de 4, )
J a b
Babcock &tVikox Mr. C. E. MacDonald Page 2 tbrch 21, 1979 5.
List of the Ebdel B safety related drawings.
We request amendment of Certificate of Compliance USA /6206/AF to accommodate the material in this transmittal.
Should you wish to discuss this matter in more detail, or if questions should arise, please do not hesitate to contact either J. P. Natters (Ext. 5966) or myself (Ext. 5211).
Sincerely, BABCOCK 6 NILCOX COMPANY C05 MERCI AL NUCLEAR FUEL PL\\NT V
.gfh/
j ))$ ' I,/
f D.N.Zeft;,M:.'
r Safety, Licensi g, and Safeguards
~
DNZ:ccm Attachments
ATTACllMENT 1 Page _1_ of 1 Babcock 6 Wilcox COMMERCIAL NUCLEAR FUEL PLANT Model B_ Shipping Container USA /6206/AF DESIGN CllANGE The top end gate pad of the strongback assembly is supported by one large diameter bolt with a ball head (for easy alignment with the fuel assembly in the loading operation) instead of four small diameter bolts as originally designed.
The following sections from the enclosed drawings illustrate the design change stated above.
Drawing Section Title Number Or View Number Description PE-53F
" Gate-Top End" Front view of top end gate showing the (2) large diameter bolts with ball heads.
PE-53F Section B-B Side view of top end gate (new design).
PE-53F Section C-C Detail of top end gate " pad" which utilizes the one large diameter bolt.
PE-53F
" Alternate Detail of original " pad" configuration Method" using the 4 small diameter bolts.
PE-53F
" Detail A" - Side Side view of " Alternate Method" also View showing the 4 small diameter bolts.
ANALYSIS The top end gate pad contacts the top end fitting of the fuel assembly to maintain its axial position during shipment.
It does not carry any dead weight load.
Any loads due to shock during shipment are supported by the 20 spring loaded grid pads of the 10 clamp bows, as well as the top end gate bolt.
The rated load in thread shear for this bolt is 3310 lbs. which is considered sufficient in this application where the total weight of the fuel assembly is only 1550 lbs.
During an extreme accident where the assembly could slip loose from the clamp bow restraints and fail the bolt, the assembly is restrained from a displacement of more than 2 inches by the top end gate.
The change from 4 small bolts to one larger bolt was made for easy alignment with the fuel assembly during the loading operation and the analysis of the hardware change show that the new configuration does not degrade the safety of the container in relation to the original design.
ATTACllMENT 2 Page 1 of 2 Babcock 6 Wilcox COMMERCIAL NUCLEAR FUEL PLANT Model B_ Shipping Container USA /6206/AF DESIGN CilANGE The hardware used to secure the strongback assembly to the shock mount frame uses one swing bolt per location instead of two T-bolts per location as originally designed.
The design change above is shown in the following sections from the drawings included with this submittal.
Drawing Section Title Number Or View Number Description PE-52F
" Shock Mount Frame This section shows side views of both View" the original design (2-T bolts) and the new design using the swing bolt system.
PE-52F View "A" Shows location of swing bolt in re-lation to the T-Support (#23).
PE-52F View "!!" 6 "Z" Shows other components used in con-junction with those shown in the
" Shock Mount Frame View" and View "A" for securing the Shock Mount Frame to the Strongback Assembly.
PE-53F Shock Mount Detail Shows another view of some of the components from those views in Drawing PE-52F.
PE-53F View A-A Cutaway side view of entire container showing the relationship of the Shock Mount Components and Strongback Assembly to the entire container.
ANALYSIS The new design consists of 16 swing bolts and nuts,16 horizontal bolts and nuts as shown in the drawings.
The swing bolts and nuts meet S.A.E.
Grade 5 standards.
The original design consisted of 32 T bolts and nuts.
The following is a comparison of the safe loads for each design.
Rated safe load of the 16 swing bolti is:
16 5/8"-18 SAE Grade 5 swing bolts @ 3,000 lbs. each = 48,000 lbs.
3,100 lbs.
4 1/2" Machine bolts 0 775 lbs. each
=
TOTAL
= 51,100 lbs.
ATTACllMENT 2 Page 2_of 2 Babcock G Wilcox COMMERCIAL NUCLEAR FUEL PLANT Model B_ Shipping Container USA /6206/AF ANALYSIS (cont'd)
The safe load of the old design is as follows:
24,800 (32) 1/2" T bolts 0 775 lbs. each
=
3,100 4 1/2" Machine 'aolts 0 775 lbs. cach
=
27,900 lbs.
TOTAL
=
1,700 lbs.
The weight of the empty strongback
=
3,100 lbs.
The weight of the two fuel bundles
=
4,800 lbs.
TOTAL
=
Both methods have a holding force of at least five (5) times the load weight and the new design is 1.8 times stronger than the older design.
Therefore this design change is of a positive nature and does not com-promise the safety of the container in terms of the original design.
ATTACllMENT 3 Page 1, of 1 Babcock 6 Wilcox COMMERCIAL NUCLEAR FUEL PLANT
-~B Shipping Container Model USA /6206/AF DESIGN CilANGE The bolt used to secure fuel assembly bow clamps to t he strongback uses spring washers on the old containers, but not on the new ones.
This design change is illustrated in the drawings listed below.
Drawing Section Title Number Or View Number Description PE-52F View "II" Illustrates how the clamp bow is secured to the lower clamp mount.
Shows both configurations (with and without spring washers).
PE-52F "F/A Clamping Mech.
Side view of entire mechanism (new and Components" design) showing parts from View "11".
PE-52F Alternate Method Side view of entire mechanism (ori-ginal design) showing parts from View "11".
PE-52F Section B-B Shows new spring loaded fuel assem-bly pressure pads that take the place of the old spring washers.
PE-52F Section B-B Same view as "B-B" above, except Alternate Method shows original design with no spring loaded pressure pads.
ANALYSIS The old spring washer design was intended to provide a mechanism to control pressure on the grids of the assembly.
The new design using spring loaded pressure pads provide better control on the clamping pressure to insure the correct setting during each loading operation.
The hard contact provided by the new flat washer also improves the rigidity of the clamp bows.
'Ihis change is an improvement from the original design since it provides additional clamp bow rigidity and a direct control on the clamping pressure applied to the fuel assembly.
t ATTAClia!ENT 4 Page 1_ of 3_
Babcock 6 Wilcox C0fth!ERCIAL NUCLEAR FUEL PLANT Ff o d e l B Shipping Container USA /6206/AF DESIGN CilANGE Assembly Holddown Pads (Fuel Cell Clamp)
As designed, the h!odel B shipping container incorporated fuel cell clamps with 8" x 1.25" dimensions.
Subsequently, it has become apparent that fuel cell clamp size should be adjusted to accommodate variations in fuel assembly cross sections that result from changes in assembly design.
It should be noted that all assemblics involved still fall within the size criteria specified in Certificate of Compliance USA /6206/AF - 5(b)(1).
In addition to the original S x 1.25 inch fuel cell clamp pad. B6W requests approval to incorporate one of two alternate pad sizes of 7.25 x 1.5 in. or 6.25 x 1.5 in. as appropriate to the assembly being shipped.
The following drawings illustrate the design change above:
Drawing Section Titic Number Or View Number Description PE-52F Fuel Cell Clamp Shows top, front, and right side views of new design holddown pads.
PE-52F Fuel Cell Clamp Shows alternate design of holddown Alternate Flethod pads.
PE-52F Section B-B Shows fuel assembly clamping assembly.
PE-52F Alternate B!cthod Shows alternate method for fuel of Section B-B assembly clamping components.
PE-52F Fuel Assembly Shows side view of components used Clamping Assembly to hold down the fuel assembly.
And Components PE-52F Fuel Assembly Side view of c..nponents (alternate Clamping Assembly design) used to hold down the fuel And Components assembly.
(Alternate b!cthod)
ATTACilb!ENT 4 Page 2 of 3 Babcock 6 Wilcox CO)lF1ERCIAL NUCLEAR FUEL PLANT Ff o d e l B_ Shipping Container USA /6206/AF ANALYSIS Acceptability of the holddown forces exerted by the three alternate clamping pad sizes may be calculated as described below:
8" x 1 1/4" pad = 10 in.
contact area = 9.568 in.
7 1/4" x 1 1/2" pad = 10.875 in.
contact area = S.671 in.
spacer grid side area = 10.448 in.
holddown pressure = P
=F h
h T
F
= holddown force h
Tests conducted by B6W have demonstrated that spacer grids will with-stand a load of 3,700 lbs. before plastica 11y deforming.
Thus:
s., = h l h /in max. holddown pressure = F
=
h 10.448 in."
7 The maximum holddown force for the shipping containers with the 8" x 1 1/4" pad was set at 375 lbs.
Thus:
@ 8" x 1 1/4" pad P
= 375 lb./9.568 in.2 = 39.2 lb./in."
375
= 43.3 lb./in.2 0 7 1/4" x 1.5" pad P
=
h 8.671 place is 160 lbs. or 15.3 lb./in.gd required to hold the fuel bundle in The minimum hold doen force per p The change to 6 1/4" x 1 1/2" pads will be necessary in order to accomo-date all possible fuel bundles manufactured by CNFP At the same time, the holddown force will be changed to 500 + 100 lb. in order to increase the safety margin over minimum required holddown force.
For 6 1/4" x 1.5" pad A = 7.475 in.
P = 600/7.475 = 80 lb./in.
h llence, the holddown pressure has been increased and the pad may fit all intended fuel bundles while remaining safely under the minimum distortion load for the spacer grids. The minimum load for any pad size will be above the minimum holddown load since the holddown load is held to a mini-mum of 170 lbs.
ATTACilMENT 4 Page 3_of 3 Babcock 6 Kilcox COMMERCIAL NUCLEAR FUEL PLANT Model B Shipying Container US'/6206/AF ANALYSIS (cont'd)
The above calculations demonstrate that adjustments to clamp pad size within the 8 x 1.25" and 6.25 x 1.5" range do not have a significant effect on the safety of the container as originally designed and tested.
INSTRUMENT SIGi!T PORTS, As indicated in Drawing PE-53F, two additional instrumentation sight ports (for accelerometers) are to be installed in the Model B containers.
Sight ports will be require <1 30 that the indicators can be inspected prior to opening the conta
..er.
As now planned, the two sight ports will be located on the Icft side and approximately 12 and 18 inches from the end of the container lid.
Tne ports, as installed, will be equivalent to those currently in use for the same purpose and do not affect container safety.
ATTACllMENT 5 Ilabcock 6 Wilcox C0!! MERCI AL NUCLEAR FUEL PLANT Model B Shipying Container USA /6206/AF
, LIST OF MODEL B DRAWINGS ENCLOSED:
Drawing Number 6 Title PE-52F Strongback Assembly and Details PE-53F Containet-Assembly and Components PE-54F Upper Weldment G Lower Weldment and Details