ML20135D388

Forwards Response to RAI Re TS Change Request 96-01-0 Re ADS Valve start-up Testing

ML20135D388
Person / Time
Site:	Limerick
Issue date:	12/05/1996
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9612090359
Download: ML20135D388 (8)

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Page 1 of 5 Limerick Generating Station Units 1 and 2 Safety Relief Valve Preventive Maintenance Program There are a total of 28 Safety Relief Valves (SRVs) installed at Limerick Generating Station (LGS);

i fourteen (14) valves on each unit, with fourteen (14) spare valves available. SRV valve bodies are tracked by serial number and are interchangeable for any location. Currently, during each refueling cycle for each unit the pilot valve assemblies for the fourteen (14) SRVs are replaced with calibrated spares. This replacement schedule is based on the SRV setpoint performance history to date, and is not expected to change unti performance improves. However, if SRV setpoint performance improves, we anticipate replacing only seven (7) SRV phot valve assemblies during each refueling cycle as required by the Technical Specifications (TS).

Furthermore, during each refueling outage, valve bodies are also replaced for those SRVs that are leaking.

In addition, additional SRV valve bodies are replaced in an effort to perform preventive rnalntenance (PM) on certain valves. For example, the table below summarizes the PM activities that have been performed during previous refueling outages on LGS, Unit 2, as well as the PM activities scheduled for future Unit 2 refueling outages.

Previous LGS Unit 2 Refueling Outages Outage Preventive Maintenance Performed 2"d Refueling Outage (2RO2) Fourteen (14) entire SRVs were replaced.

(January 1993) 3'd Refueling Outage (2RO3) Fourteen (14) phot valve assemblies were replaced.

(January 1995)

Future LGS Unit 2 Refueling Outages Outage Preventive Maintenance Scheduled 4* Refueling Outage (2RO4) Start of the current PM philosophy. The 2A,2B,2C, and (January 1997) 2D SRVs will be replaced for PM . The 2E,2G, and 2H SRVs will be replaced due to leakage.

5* Refueling Outage (2RO5) Any SRVs that are leaking will be replaced. In addition, (AprH 1999) main valve bodies will be replaced for approximately three (3) or four (4) SRVs if they had not been maintained during the 2RO4 Refueling Outage.

6* Refueling Outage (2RO6) Any SRVs that are leaking will be replaced. In addition.

(AprH 2001) valve bodies will be replaced for any valves not maintained during 2RO4 and 2ROS. The current goal is to rnalntain all fourteen (14) SRV bodies for each unit over three (3) refueling cycles.

Pilot valve assemblies replaced during refueling outages are as-found tested, repaired (as necessary), and as-left tested. The testing is performed by Wyle Laboratories in sccordance with their testing procedure, which has been reviewed by PECO Energy. The procedure l

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, Page 2 of 5 institutes Target Rock Corporation testing requirements. PECO Energy specifies the setpoint and leakage test pressure Any repairs are performed by Target Rock Corporation, in accordance with their procedures. Repairs include cleaning, lubrication, machining, impping, and new gaskets and parts, as required. Wyle Laboratories and Target Rock Corporation provide test and repair reports for the work performed Target Rock Corporation works under PECO Energy's American Society of Mechanical Engineers (ASME) Code,Section XI, Repair and Replacement Program.

Main valve bodies are disassembled and inspected after decontamination. Minimum maintenance includes renewal of gasket, lapping of seat and disc, and leak testing with nitrogen.

Parts occasionally needing replacement are: valve disc, seat, spring, piston rings, and fasterers.

PECO Energy implements the appropilate inspection guidance specified in General Electric (GE)

Service Information Letter (SIL) No.196, " Summary of Recommendations for Target Rock Main Safety / Relief Valves," in the Target Rock Corporation purchase order, and requires preliminary nitrogen test acceptance at 200 psig. Target Rock Corporation provides repair and parts reports to PECO Energy, and any repairs are performed in accordance with Target Rock Corporation's procedures, which are approved by PECO Energy.

After any repairs, main valves are steam tested for stroke and post-test leakage in accordance j with Wyle Laboratories' test procedure. Wyle Laboratories provides a test report which includes test results_ Main valve testing is a restricted flow test. The valve outlet is restricted so that only limited steam flow is permitted. ire valve disc travel is not restricted by this test, but steam flow is limited by a gag device Test stand steam supply and steam recovery capability requires limited flow testing.

Exhibits l Exhibit 1 - Pilot Assembly Hoisting l Exhibit 2 - Limerick Two Stage Target Rock SRV l Exhibit 3 - Valve Assembly (Exploded) l l

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