ML20002A589
| ML20002A589 | |
| Person / Time | |
|---|---|
| Site: | 07105939 |
| Issue date: | 10/14/1980 |
| From: | Cunningham G GENERAL ELECTRIC CO. |
| To: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 17734, NUDOCS 8011200205 | |
| Download: ML20002A589 (2) | |
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ENGINEERING GENERAL ELECTRIC COMPANY, P.o. sox 460, PLEASANToN, CALIFCANIA 945ee DIVISION l
October 14, 1980 C. E. MacDonald, Chief Transportation Certification Branch Division of Fuel Cycle and Material Cafety U.S. Nuclear Regulatory Comission Washington, D.C. 20555 Ref:
(1) Certificate of Compliance No. 5939 (2) Letter, C. E. MacDonald to G. E. Cunningham, 7/25/80 (3) Request for Extension, G. E. Cunningham to C. E. MacDonald, 9/26/80
Dear Mr. MacDonald:
This letter is in response to your questions of July 25,1980 (Ref. 2) con-cerning the G.E. Model 1500 shipping container (Certificate of Compliance 5939).
Your first questien concerned the welds shown on Drawing No. 706E441, Rev. 7.
The changes are addressed as follows:
(a) The F6 weld symbol was modified to provide for a flush ground groove weld between the cask flange plate (P1) and the final lid step cylinder (P7). This makes the weld joint strenger and prevents centamination from entering the gap that was previously at this joint.
(b) The F10 weld symbol was changed from a 3/16" fillet to a 1/4" grcund flat groove joint. As the 7./4" groove weld represents a full penetratien weld, it is stronger than tne former 3/16" partial penetraticn joint.
Therefore, no reduction in weld strength cccurred because of this change.
(c) The F12 weld symbol was added to clarify the design. Earlier versions of the print implied a typical 3/16" groove or a fillet weld in the area. Either weld would be inappropriate for the assembly of the 0.065" tube to a 1/4" plate. The 1/16" flush ground groove weld, however, provides strength equal to or exceeding the strength of the tube material.
(d) The H10 weld symbol was changed frem a 3/16" fillet to a 3/16" ground flush groove weld. According to the AWS Structural Welding Code, a partial penetratien groove weld is always equal to or strenger than an equivalent si:e fillet weld (Ref: ANS D1.1, Table 10.4.1 - Allowable Stresses in Welds),
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GENERAL @ ELECTRIC C. E. MacDonald October 14, 1980 (e) Re H12 weld symbol was changed to allcw a convex contour to the groove weld, and this results in no reducticn to the weld strength.
The second questien ccncemed the optional cask lid shown on Drawing No.
706E441 Rev. 12. This optional lid is nothing more than the original cask lid with 1/2"-thick steel rings added by welding. Rese rings served as spacers between the cask lid plug and internal cavity shielding liners (no longer used).
It was considered impractical to remove the rings after the use of the liners was discontinued, particularly since their additien effectively increased the thickness and the strength of the previoitsly approved lid. All of the containers (with the optional and the standard lid) are leak tested at least annually using a gas or soap bubble test method described in ANSI N14-5-1977 to assure that any leak through the assembly welds is <1 x 10-3 cc/sec.
He third question concemed the revised seal shown en Drawing No.1290D4690.
His seal is constructed of the same material (silicone mbber) as the pre-vicusly approved seal. However, the variable cross-section of the advanced seal design allows the' seal to become effective at a much lower clamping pressure than the conventional flat seal.
In addition, the aluminum ring provides support for the seal and holds it in positien when no clamping force is applied. He aluminum ring also acts as a c:snpression limiter.
which prevents high compression loads as might occur under accident condi.
tions. Rese improved seals have been successfully leak tested to <1.3x10-0 cc/sec.
As requested in your letter (Ref. 2), revised pages to the consolidated Safety Analysis Report will be submitted (the target date is 10/31/80).
However, we request that the infomation in this letter be used for evalu-ation in order to egedite our request for extension dated September 26, 1980.
Stauld tnere be additional infomation requested for the seal, we could continue to snip using the old seal, although we believe the revised seal provides a superior closure. Also, we would not object for the purposes of this extension to accept the revised loading requirements previously re-quested for the Models 100, 200, 400, 500 and 1600.
Sincerely, W
G. E. Cunningham Senior Licensing Engineer
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