ML20098A721

Submits Addl Info in Response to 831207 Request for Info Re NUREG-0737,Item II.B.2, Design Review of Plant Shielding. Results of Shielding Analysis Indicate Max post-LOCA Dose Rate on Floor Above Filters Is Approx 1.3 M/H

ML20098A721
Person / Time
Site:	Oyster Creek
Issue date:	09/18/1984
From:	Fiedler P GENERAL PUBLIC UTILITIES CORP.
To:	Paulson W Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.2, TASK-TM NUDOCS 8409250230
Download: ML20098A721 (3)

Text

r GPU Nuclesr Corporation

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')irect Dial Number:

September 18, 1984 Mr. Walter A. Paulson, Acting Chief Operating Reactors Branch No. 5 Division of Licensing U.S. Nuclear Regulatory Comission Washington, DC 20555

Subject:

Oyster Creek Nuclear Generating Station Docket No. 50-219 NUREG-0737, Item II.B.2 In accordance with your letter of December 7,1983, which requested additional information relative to NUREG-0737, Item II.B.2 " Design Review of Plant Shielding", GPU Nuclear Corporation provided a response on June 21, 1984. By telephone conversation on August 28, 1984 your staff i:Aicated that the NRC's evaluation of SEP Topic XV-19 " Radiological Consequences of a LOCA" had not considered charcoal filter loading during the course of an accident. Thus, the cancellation of the Standby Gas Treaticant System (SGTS) Tie-in modification could not be granted based on the above evaluatioi.

As a result, GPUN contracted United Enginee s & Constructors Inc. (UE&C) to analyze post-LOCA iodine loading for the SGTS charcoal filter. On September 11, 1984, a meeting was held at UE&C between GPUN personnel and Mr. G. Kelly of NRC Region I to review the results of the analysis. The analysis demonstrates that post-LOCA iodine loading for the SGTS charcoal f!1ter will not reach the Regulatory Guide 1.52 limit of 2.5 mg per gram of charcoal until the end of 30 days after a LOCA.

These results, sumarized in Table I, have been obtained by conservatively assuming that primary containment leaks at the design value of 0.5% per day, for the entire 30 day duration. The design leakage is determined at the Primary containment design pressure of 62 psig. However, thermo-hydraulic analyses (reference G.E. Primary Containment Design Report), show that the post-LOCA peak pressure is only 33 psig, and the pressure drops to atmospheric level in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> due to operation of the Containment Spray System. Therefore, for all practical purposes, the leakages from primary containment will be reduced to negligible levels within the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the actual post-LOCA 84c9250230 840918 DR ADOCK 05000 go GFU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation

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iodine loading will be well below the values presentea in Table I.

The

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analy:is also conservatively assumes that all the iodines will be accumulated in one SGTS filter train (one out of two redundant filter trains).

The post-LOCA iodine loading should not cause any significant change in filter efficiency for the duration of tha accident. Therefore,

- cancellation of the SGTS tie-in modificati?;n is justified.

The results of the shielding analysis indicate that the maximum post-LOCA dose rate on the floor, directly above the filters, is only approximately 1.3 mr/hr. The SGTS filters are well shielded, below grade and inside a concrete pipe tunnel.

Therefore, they do not pose any post-LOCA access restrictions to any vital areas.

Should you require any further information on this subject, please contact Mr. Michael Laggart, Manager BWR Licensing at (201) 299-2341.

Very truly yours, Vice Presiden'. and Director Oyster Creek 1r:0394e Enclosure cc: Mr. G. Kelly U.S. Nuclear Regulatory Commission Region I ti31 Park Avenue King of Prussia, Pa. 19406 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, N.J.

08731

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ENCEOSURE 1~

TABLE 1

• .~

Post-LOCA Iodine Loading for SGTS Charcoal Filter b

Iodine Loading (mg of iodines per gram of charcoal)

Time

- Stable Iodines Radioactive Iodines Total r

0 0

0 0

12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 1.8 x 10-2 2.1 x 10-3 2.0 x 10-2

-24 hours

'5.5 x 10-2 4.6 x 10-3 5.9 x 10-2

.3 days:

0.24 1.0 x 10-2 0.25 10 days-0.88 1.8 x 10-2 o,90 20 days 1.8 1.5 x 10-2 1.8 30 days.

2.6 9.5 x 10-3 2.6 4

S 9

O O 4

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