ML19262B470
| ML19262B470 | |
| Person / Time | |
|---|---|
| Site: | 07106698 |
| Issue date: | 12/12/1979 |
| From: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML19262B469 | List: |
| References | |
| NUDOCS 7912280037 | |
| Download: ML19262B470 (4) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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NRC CERTIFICATE OF COMPLIANCE
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Docket No. 71-6698 N0. 6698 FOR RADI0 ACTIVE
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MATERIALS PACKAGES
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ORDER AMENDING CERTIFICATE AND TERMINATING IN PART ORDER TO SHOW CAUSE I
By Order dated April 6, 1979, the Director, Office of Nuclear Material Safety and Safeguards suspended the use of seven casks used for transpor-tation of spent reactor fuel pending a showing that these casks were of Compliance No. 6698 (Revision 8)._9 gn approved by the NRC in Certi fabricated in accordance with the de i
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As required by the April 6th Order as a condition to rescission of the ordered suspension, the Nuclear Assurance Corporation (NAC) and Duke Power Company have reviewed their quality assurance records and have made physical measurements of five of the q/ ected casks (Serial Nos. NAC-1A, NAC-18, ff NAC-lC, NAC-lD, and NAC-lE).f The Commission's Office of Inspection and Enforcement has inspected the quality assurance records of the casks built by Excelco Developments, Inc. for NAC.
The results of these various reviews and inspections indicate that two casks (Serial Nos. NAC-1 A and NAC-lC) are bowed and therefore do not meet the requirements of Certificate of Compliance No. 6698.
It is not known at this time whether the cause of the bowing in these two casks occurred during their manufacture or during their actual use. The NRC staff has found that 1/ Seven casks designated as Model No. NFS-4 have been fabricated to the design approved in the Certificate: Serial Nos. NAC-1A, NAC-1B, NAC-lC, NAC-lD, NAC-lE, NFS-4A, and NFS-4B. These casks are used to transport spent reactor fuel. The basis for the April 6th Order was the discovery that measurements of the dimensions of the inner shell of one cask (Serial No.
NAC-1A) indicated that the shell was warped or bowed, but the exact cause or extent of the warp or bow was not known at the time.
2/ These casks were originally manufactured by Excelco Developments, Inc.,
Tor NAC. Duke Power Company is the present owner of casks Serial Nos. NAC-1A and NAC-1B. NAC owns the remaining casks in the NAC-1 series. Casks Serial Nos. NFS-4A and NFS-48, owned by Nuclear Fuel Services, Inc. (NFS), were also subject to the April 6th Order, but NFS has not submitted any information in response to the Order. Accordingly, the suspension as provided in the April Order remains in full effect with respect to these two casks.
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. casks Serial Nos. NAC-18, NAC-1D, and NAC-lE substantially conform to Certificate of Compliance No. 6698 (Revision 8), except for certain minor differences that are unrelated to bowing or warping of the cask cavity shells.3/ Therefore, the NRC staff believes that these three casks can be returned to service, subject to certain restrictions incorporated in Revision 9 to Certificate of Compliance No. 6698 (attachment to this Order and discussed in Part II infra), without undue risk to the health and safety of the public.
II While the review of casks Serial Nos. NAC-1B, NAC-10, and NAC-lE show that these casks conform to the design authorized by Certificate of Compliance No. 6698 (as revised to include the minor technical amendments discussed in footnote 3), the staff has determined the three casks should not be returned to unrestricted service without further technical evaluation, on the basis that:
3/ As part of the quality assurance review under the April 6th Order, Nuclear
'ssurance Corporation (NAC) reviewed and compared the drawings approved in Certificate No. 6698 with fabrication drawings to which the casks were actually built, reviewed the quality assurance records, and made physical measurements of the casks' cavities. This review indicated that certain tolerances and dimensions on the fabricated casks differed from those shown on Nuclear Fuel Services (NFS) Drawing No. E10080 (Revision 16), which is the drawing approved in Certificate of Compliance No. 6698.
By letters dated June 8, July 26, and October 31, 1979, NAC requested an amendment to Certificate of Compliance No. 6698 to incorporate changes in dimensions, tolerances, and notations, that were unrelated to bowing or warping of the cask cavity shells. Revising the Certificate to include these requested changes would resolve the discrepancies between the drawings approved in Certificate No. 6698 (Revision 8) and the as-built casks, Serial Nos. NAC-1B, NAC-10, NAC-lE.
NAC has requested that Certificate of Compliance No. 6698 be amended to incorporate Revision 19 of NFS Drawing No. E10080 as the approved design drawing. Casks Serial Nos.
NAC-18, NAC-lD, and NAC-lE have been constructed in accordance with Revision 19 to Drawing No. E10080. T'e staff is issuing Revision 9 to Certificate No. 6698 (attached as Appendix A to this Order) to incorporate the requested changes as well as to impose various restrictions further described in this Order. All items identified in the NRC's inspections will be resolved to the NRC's satis-faction with the incorporation of Revision 19 of Drawing No. E-10080 and revised Condition No.13 into Certificate of Compliance No. 6698 (Revision 9).
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the bowing observed in casks Serial Nos. NAC-1A and NAC-lC, both of which are of the same design as the other casks, may be an indication that casks of this design are susceptible to buckling of the inner shell in unrestricted use; 2.
the cask design has not been analyzed to show that the inner shell would not buckle in unrestricted operation; and 3.
it cannot be concluded without such analysis that the cask would meet the requirements in 10 CFR Part 71 under Normal and Hypothetical Accident Conditions.
Accordingly, Certificate of Compliance No. 6698 has been revised (Revision 9) to include additional restrictions which would permit limited use of casks Serial Nos. NAC-1B, NAC-lD, and NAC-lE, and which would also require certain additional inspections of the casks at periodic intervals. The staff believes these restrictions are sufficient to assure the integrity of the inner shell under normal conditions of transport and that the possibility of buckling under accident conditions would be reduced.
Revision 9 to the Certificate reduces the maximum decay heat load of the contents permitted in the cask from 11.5 kilowatts to 2.5 kilowatts. The casks are also required to be shipped dry (i.e., water is no longer permitted in the cask cavity during shipment). These provisions will substantially reduce the pressures within the cask cavity under the normal and hypothetical accident conditions, specified in 10 CFR Part 71.
In addition, the temperatures and thermal gradients through the cask walls and longitudinally along the shells would also be reduced. These restrictions will lower the stresses present in the inner shell during use of the casks under normal and accident conditions.
The revised Certificate also requires the inner shell of each cask to be inspected and measured at intervals not to exceed six months. The casks are to be withdrawn from service if the measurements indicate any changes
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in the dimensions of the inner cavity. Also, the cask cavity is required to be pressure tested quarterly for possible leakage.
Even if the inner shell were to buckle under the hypothetical accident conditions in 10 CFR Part 71, and if this should lead to a violation of the integrity of the inner shell, the amount of material released would not be expected to exceed the amount pennitted in 10 CFR Part 71 based on the guidance provided in Regulatory Guide 25.
III Accordingly, pursuant to the Atomic Energy Act of 1954, as amended, and the Commission's regulations in 10 CFR Parts 2 and 71, IT IS HEREBY ORDERED THAT:
(1) Certificate of Compliance No. 6698, Revision 9, supersedes in its entirety Certificate of Compliance No. 6698, Revision 8, dated October 25,1978; and 1648 068
. (2) The suspension of the use of NAC casks with Serial Nos. NAC-1B, NAC-lD, and NAC-lE is hereby rescinded.
The Order of April 6, 1979, except as stated above, remains in effect in accordance with its terms.
IV Any person who has an interest affected by this Order may request a hearing, within twenty (20) days of the date of this Order, with respect to this Order. Any request for a hearing shall be addressed to the Director, Office of Nuclear Material Safety and Safeguards, U. S. Nuclear Regulatory Commission, Washington, D.C. 20555. Any request for a hearing shall not stay the immediate effectiveness of this Order.
If a hearing is requested by a person whose interest is affected by this Order, the Commission will issue an order designating the time and place of hearing. The issue to be considered at such hearing will be:
Whether the restrictions added by Revision 9 to Certificate of Compliance No. 6698 are necessary to p,rovide reasonable assurance that the casks will meet the Normal and Hypothetical Accident Conditions in accordance with 10 CFR Part 71.
FOR THE U.S. NUCLEAR REGULATORY COMMISSION
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William' J. Dircks, Director Office of Nuclear Material Safety and Safeguards Effective Date:
DEC 121979 Silver Spring, Maryland 1648 069 a
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