ML20213G312

Informs That Search of Nonfuel SNM Records Revealed 23 Fission Chamber Detectors Not Included in Inventory Required by 10CFR70.51(d).Detectors Removed After Use in in-core Neutron Monitors & Transferred to Radwaste Storage Area

ML20213G312
Person / Time
Site:	Sequoyah
Issue date:	10/31/1986
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8611180029
Download: ML20213G312 (2)

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CHATTANOOGA. TENNESSEE 37401 5g Q If T8 Nf b SBT 311988 U.S. Nuclear Regulatory Commission Region II ATTN: Dr. J. Nelson Grace, Regional Administrator i 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Dear Dr. Grace:

SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - SPECIAL NUCLEAR MATERIAL (SNM)

ACCOUNTABILITY This report is being made pursuant to 10 CFR 70.52. As a result of a problem concerning nonfuel SNM accountability identified by TVA at our Browns Ferry Nuclear Plant, a detailed search of the nonfuel SNM records was performed at Sequoyah. This record search identified 23 fission chamber detectors that have not been included in the annual physical inventory required by 10 CFR 70.51, paragraph d. The detectors are used in the incore neutron i s monitoring system of the reactors to monitor neutron flux. Following removal from service in the reactors, these detectors have been considered radwaste and'not accounted for as SNM.

1 Since licensing, SQN has received 62 of these detectors each of which contained approximately 4.4mg of uranium, highly enriched in uranium-235. SQN SNM records show that two detectors were sold and transferred to another utility and therefore are no longer inventoried at SQN, 12 are presently in use (6 per unit), 25 are located in the radioactive materials storage area, and 23 have been transferred to the radwaste storage area after use in one of the reactors.

To date, a physical inventory of the detectors transferred to radwaste has verified the location of 12 detectors. Documentation exists which provides SQN plant management with a high degree of confidence that the remaining 11 detectors are.in the high-level radwaste storage area. A complete search of this area has not been conducted because of the high personnel exposure that would result.- Management is developing plans to complete the search of the high-level radwaste storage area while minimizing personnel exposure. During this process the location of the 11 remaining detectors will be verified and documented.

't SQN plant procedures which implement SNM accountability requirements presently ensure all other SNM (fuel and nonfuel) undergo an annual physical inventory.

These procedures are being revised to ensure that the incore detectors are accounted for in the subject inventory following their removal from service in the reactor (s).

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Dr. J. Nelson Grace ( 3 I I$$3 Upon completion of the cleanout of the high-level radwaste storage area, any discrepancy in the SNM inventory will be documented and reported as required.

Very truly yours, TENNESSEE VALLEY AUTHORITY 2

R. idley, irector Nuclear Saf ty and Licensing cc: Mr. James Taylor, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. G. Zech Director, TVA Projects U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323