ML20083N335

Responds to NRC RAI Re Util TS Change Request 94-32-0, Submitted by to Delete Requirements of Section 3/4.3.8 for Turbine Overspeed Protection Sys

ML20083N335
Person / Time
Site:	Limerick
Issue date:	05/11/1995
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9505230029
Download: ML20083N335 (4)

Text

P Ctation Support Department PECO ENERGY = J"glff=;L ,,

965 Chesterbrook Boulevard Wayne, PA 19087-5691 May 11,1995 Docket Nos. 50-352 50-353 Ucense Nos. NPF-39 NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

Subject:

Limerick Generating Station, Units 1 and 2 Technical Specification Change Request No. 94-32-0 Response to Request for Additional Information Gentlemen:

This letter is being submitted in response to the NRC's request for additional information concerning Limerick Generating Station (LGS), Units 1 and 2, Technical Specification (TS)

Change Request No. 94 32-0. PECO Energy submitted TS Change Request No. 94-32-0 by letter dated August 31,1994, requesting that the TS of Operating License Nos. NPF-39 and NPF-85 for LGS, Units 1 and 2, respectively, be amended to delete the requirements of Section 3/4.3.8 for the Turbine Overspeed Protection System.

Subsequently, during a telephone conversation between PECO Energy and NRC representatives, the NRC requested that we provide additional information regarding this submittal. This additional information is being submitted under affirmation and the required affidavit is attached.

The following information is being supplied in response to the four questions asked by the NRC representatives.

1) Provide the Plant specific technical justification for removing the Turbine Overspeed Requirements from the Technical Specifications.

Ans. As documented in the NRC's Safety Evaluation Report (SER), dated August 1983 In Section 3.5.1.3, relating to the operation of the LGS Units 1 and 2, the probability of unacceptable damage to safety related systems, structures, or components as a result of turbine missiles is acceptably low. Redundant and diverse turbine overspeed protection is provided by the electro-hydraulic turbine speed governor system, mechanical overspeed trip mechanism and electrical overspeed trip system, in accordance with manufacturer's recommendations, LGS performs actual overspeed

- testing of the turbine to verify the operation of the mechanical and electrical overspeed devices. Main turbine rotor and valve Inspections are conducted in accordance with the

' Main Turbine Maintenance Plan'.

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• May 11,1995 Page 2 The Low Pressure Turbine rotors at LGS are the original keyway / shrunk-on disk type rotors. The turbine rotor inspection criteria outlined in the Main Turbine Maintenance Plan ensures that the probability of occurrence of a turbine generated missile is low.

Following scheduled inspections o' the Low Pressure rotors, the findings are evaluated by the manufacturer, Genera! Electric Company, using a probabilistic method developed at the request of the NRC and used to support the Main Turbine Maintenance Plan .

Following these evaluations, General Electr'c's recommendations are implemented, as required, to maintain the turbine misslie generation probability within LGS Ucensing requirements.

2) List any modifications to the Turbine-Generator since the original SER was issued.

Ans. There have been no physical modifications to the turbine-generators since the original SER was issued.

There has been a procedural modification that was the result of the manufacturer's recommendations which resulted in a routine prewarming of the LGS Unit 1 Low Pressure rotor prior to start-up following extended / major outages.

3) Provide the success / failure history of the Turbine Overspeed system for both LGS units.

List the number of times the systems have been tested, the correction of any deficiencies, and any documented overspeed events.

Ans. To date, approximately 900 valve stroking surveillance tests have been conducted in accordance with TS Section 3/4.3.8. No valve faltures have been experienced during operational testing that would have prevented valve closure required for overspeed protection. There have been no operational overspeed events to date on either unit.

4) A vendor recommendation regarding Turbine Overspeed protection system testing frequency exists in the LGS SER (Supplement 3). How does this TS Change Request address vendor recommendations? Does this TS Change Request violate vendor recommendations?

Ans. In Supplement 3 to the LGS Safety Evaluation report dated October 1984 (Section 10 Steam and Power Conversion System,10.2 Turbine Generator), there is a reference to a General Electric Technical Information Letter (TIL) 969 dated May 22,1984. In this TIL the recommended turbine control valve surveillance design Interval was changed from weekly to monthly.

Main-Turbine, valve stroke testing for all turbine control and stop valves is performed in accordance with the vendor recommendation as so noted in GE TIL-969. This TS change request deals with deleting the Turbine Overspeed Protection System from TS and relocating these requirements into another licensee controlled document where any changes would be governed by the 10CFR50.59 process. The requirements for operation and survolllance conform with the surveillance intervals as outlined in GE TIL-969 and will remain unchanged. Removal of the Turbine Overspeed Protection system from TS and relocating these requirements into another licensee controlled document will not virJate any vendor recommendations.

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' If you have any questions or require any additional inforrnation, please contact us.

Very truly yours, h fd j=b,/z G. A. Hunger, Jr.

Director . Licensing Enclosure cc: T. T. Martin, Administrator, Region I, USNRC (w/ enclosure)

N. S. Perry, USNRC Senior Resident inspector, LGS (w/ enclosure)

R. R. Janati, PA Bureau of Radiological Protection (w/ enclosure) l

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COMMONWEALTH OF PENNSYLVANIA  :

ss.

COUNTY OF CHESTER  :

W. H, Smith, Ill, being first duly sworn, deposes and says: That he is Vice President of PECO Energy Company, the Applicant herein; that he has read the foregoing Response to Request for Additional Information invoMng Technical Specifications Change Request No. 94-32 0 for Umerick Generating Station, Unit 1 and Unit 2, Facility Operating Ucense Nos. NPF-39 and NPF-85, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, Information and belief.

w i Vice President l

Subscribed and sw rn to l before me this l[ day of A 1995.

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