ML19210E494

Responds to NRC 790924 Ltr Re Violations Noted in IE Insp Repts 50-277/79-14 & 50-278/79-16.Corrective Actions: New Shutdown Procedure & Removal of Identified Leaking Fuel Assemblies

ML19210E494
Person / Time
Site:	Peach Bottom
Issue date:	10/15/1979
From:	Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Galen Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19210E491	List: ML19210E494
References
NUDOCS 7912050105
Download: ML19210E494 (3)

Text

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PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 SHIELDS L. D ALTPO FF stacTaic eno cTioN october 15, 1979 Re: Docket Nos.: 50-277 50-273 Inspection No.: 50-277/79-14 50-278/79-16 Ii r . George H. Smith, Chief Fuel Facility and 'f at e rials Safety 3 ranch U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Smith:

Your letter of September 24, 1979, forwarded combined Inspection Reports 50-277/79-14 and 50-278/79-16 which were conducted on June 22, 1979. Appendix A to your letter addresses an iten which did not appear to be in full c omp lianc e with Nuclear Regulatory Commission requirements. This item is categorized as an infraction and is restate d below with our response.

Technical Specification 3.8.C.1 states, "The release rate of gross activity except for halogens and particulates with half lives longer than eight days shall not exceed:

9 1498 014 7912050 g/.

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Mr. George H. Smith Page 2 ns E + $L Oiv <1 0 24 2.0 X 10 F MPC i where:

Qs = combined units 2 & 3 off gas stack release rate in Ci/sec E =

average Lf energy of release in Mev.

Qiv = combined units 2 & 3 release rate in C1/sec from reactor building ventilation exhaust stack MPC t = as defined for radionuclide i in column 1, of Appandix B 10 CFR 20 assuming a 13 minute old off gas mixture.

Contrary to the above, on June 21, 1979, the release rate of gross activity, excluding halogens and particulates with half lives longer than eight days, exceeded the Technical Specificatio. limit by a factor of 1.17 ror a period of ten minutes.

Response

The gaseous release in excess of Technical Specification which occurred on June 21, 1979 was reported to the NRC as Licensee Event Report 3-79-20/IP. The prompt notification was telecopied to Mr. 3. H. Grier, Office of Inspection and Enforcement on June 22, 1979. A followup report was provided on July 6, 1979. These two documents described the cause of the releas. and immediate corrective actions taken.

The Unit 3 reactor was removed from service due to the loss of the offgas recombiner system (mechanical compressor failed).

Primary coolant pressure was reduced to approximately 500 psig while recovery operations were in progress. This depressurization of the primary coolant system following reactor shutdown introduced non-condensible fission product gases into the condenser. During the plant startup, the mechanical vacuum pump was used in accordance with normal startup procedures to obtain condenser vacuum. The use of the nechanical vacuum pump resulted in a gaseous release rate in excess of Technical specification limits by transferring some of the gaseous fission product inventory in the condenser directly to the main stack.

Upon indication of a rapid increase in the main stack release rate, the mechanical vacuum pump vas immediately shutdown.

Technical Specification release limits were exceeded for less than 10 minutes during this transient and the maximum site gaseous release rate was approximately 117 7. of the Technical Specification limit. Following the initial high release rate,

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M'r . Gdorge H. Smith Page 3 air was admitted into the condenser to provide dilution gas during the evacuation of the condenser air space. This permitted establishing a condenser vacuum without again exceeding Technical Specification limits. During this event, concenser pressure was always subatmospheric.

An investigation of this occurrence uas performed as indicated in the July 6, 1979, Licensee Event Report 3-79-20/1T to determine whether procedural or equipment modifications were required to prevent recurrence. This investigation resulted in a special shutdown instruction to account for higher than normal offgas activities. During the recent Unit 3 end-of-cycle s h u t d o'in , the special shutdown instruction was successfully used to maintain condenser vacuum and release rates remained well below Technical Specification limits.

During the present refueling outage on Unit 3, all fuel assemblies being returned to the core have been sippe d to locate and eliminate failed fuel elements.

The new shutdoun procedure and the removal of the identified leaking fuel assemblies from the reactor should prevent reeirrence.

Very truly yours,

,_ amw *-*

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