ML20246G354

Forwards Requests for Addl Info Re Gaps in Boraflex of High Density Spent Fuel Racks.Response Requested by 891015

ML20246G354
Person / Time
Site:	Grand Gulf
Issue date:	08/25/1989
From:	Kintner L Office of Nuclear Reactor Regulation
To:	Cottle W SYSTEM ENERGY RESOURCES, INC.
References
TAC-72718, NUDOCS 8909010001
Download: ML20246G354 (4)

Text

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August 25, 1989 Docket No. 50-416 DISTRIBUTION See next page Mr. W. T. Cottla Vice President, Nuclear Operations System Energy Resource . , Inc.

P. O. Box 23054 Jackson, Mississippi 39205

SUBJECT:

GRAND GULF NUCLEAR STATION, UNIT 1 - GAPS IN BORAFLEX OF HIGH DENSITY SPENT FUEL RACKS (TAC NO. 72718)

By letter dated February 27, 1989, System Energy Resources, Inc., (the licensee) provided the results of criticality analyses and a description of the Boraflex surveillance program for the high density spent fuel racks of Grand Gulf Nuclear Station, Unit 1. The criticality analyses and surveil- <

lance program are needed to assure the safety of the storage racks because of the presence of gaps found in the Boraflex panels of the racks.

The NRC staff is reviewing your February 27, 1989 submittal and finds addi-tional information is required regarding the surveillance program for the Boraflex panels of the racks. In order to support our review schedule, you are requested to respond to the enclosed request by October 15, 1989.

The reporting and/or recordkeeping requirements of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P. L.96-511.

/s/

Lester L. Kintner, Senior Project Manager Project Directorate 11-1 Division of Reactor Projects -I/II Office of Nuclear Reactor Regulation

Enclosure:

Request for Additional Information cc w/ encl:

See next page +

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Mr. W. T. Cottle System Energy Resources, Inc. Grand Gulf Nuclear Station (GGNS) cc:

Mr. T. H. Cloninger Mr. C. R. Hutchinson Vice President, Nuclear Engineering GGNS General Marager

& Support System Energy Resources, Inc.

System Energy Resources, Inc. P. O. Box 756 P. O. Box 31995 Port Gibson, Mississippi 39150 Jackson, Mississippi 39286 Robert B. McGehee, Esquire The Honorable William J. Guste, Jr.

Wise, Carter, Child, and Attorney General Caraway Department of Justice P. O. Box 651 State of Louisiana Jackson, Mississippi 39205 Baton Rouge, Louisiana 70804 Nicholas S. Reynolds, Esquire Office of the Governor Bishop, Liberman, Cook, Purcell State of Mississippi and Reynolds Jackson, Mississippi 39201 1400 L Street, N.W. - 12th Floor Washington, D.C. 20005-3502 Attorney General Gartin Building Mr. Ralph T. Lally Jackson, Mississippi 39205 Manager of Quality Assurance Entergy Services, Inc. Mr. Jack McMillan, Director P. O. Box 31995 Division of Solid Waste Management Jackson, Mississippi 39286 Mississippi Department of Natural Resources P. O. Box 10385 Mr. John G. Cesare Jackson, Mississippi 39209 Director, Nuclear Licensing System Energy Resources, Inc. Alton B, Cobb, M.D.

P. O. Box 469 State Health Officer 1 Port Gibson, Mississippi 39150 State Board of Health l P. O. Box 1700 Mr. C. B. Hogg, Project Manager Jackson, Mississippi 39205 Bechtel Power Corporation P. O. Box 2166 President Houston, Texas 77252-2166 Claiborne County Board of Supervisors Port Gibson, Mississippi 39150 Mr. H. O. Christensen Senior Resident Inspector Regional Administrator, Region II U.S. Nuclear Regulatory Commission U. S. Nuclear Regulatory Commission Route 2, Box 399 101 Marietta Street Port Gibson, Mississippi 39150 Suite 2900 Atlanta, Georgia 30323

c,.

g Enclosure

, REQUEST FOR. ADDITIONAL.INFORMATION REGARDING THE.HIGH. DENSITY-SPENT-FUEL. RACK EORAFLEX GAP-SURVEILLANCE. PROGRAM

_ GRAND. GULF NUCLEAR. STATION . UNIT.1 Attachment 2 to the System Energy Resources, Inc., letter dated February 27, 1989 i described the surveillance program for measuring gaps in the Boraflex of the high i density spent fuel racks. Additional information is needed regarding Boraflex '

gaps as described below.

1. The sample of cells selected (104 in a high gamma flux region) is ii only about 2% of the 4348 cells in the spent fuel pool and is based on the assumption that radiation is the only significant parameter causing gaps.

What assurance is there that the other 98% of the cells will have less 1 adverse gaps than the cells monitored?

2. The fabrication process is believed to contribute to the formation of j gaps under gamma radiation. Describe the procedure used in the fabrication j of the Boraflex panels, including the use of adhesives on mechanical devices that can restrain the Boraflex from shrinkage under gamma radiation.

3. Describe _the analysis method for determining that measured gap sizes and distribution are bounded by the gaps assumed in the criticality calcula-tion and that the surveillance intervals are conservatively selected to predict maximum gap growth.

4. Describe the criterion for a finding of excessive Boraflex gaps in panels or excessive degradation of coupon specimens and the actions to be taken if such degradation is found.

5. Provide a discussion of the potential for downward movement of Boraflex segments within the cladding under vibration of the racks caused by inserting or removing fuel assemblies or the design basis earthquake.

6. Describe administrative controls that will be used to implement the surveillance program and actions resulting from the tests, including a description of the program to be included in the Updated Final Safety Analysis Report.

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i DISTRIBUTION i

etDocket: file NRC PDR Local PDR ,

PDII-1 Reading S. Varga 14-E-4 G. Lainas 14-H-3 E. Adensam 14-B-20 P. Anderson 14-B-20 L. Kintner 14-B-20 OGC(For inform. Only) 15-B-18 E. Jordan MNBB-3302 B. Grimes 9 ?-2 W. Hodges 8-E-23 K. Kopp 8-E-23 G. Bachi 8-D-22 J. Win 8-H-7 ACRS(g) 10 P-315 GRAND GULF FILE Ofbt 1l,

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