ML20080Q515

Forwards Response to NRC 830511 Request for Addl Info Re NUREG-0737,Item II.K.3.28, Qualification of Automatic Depressurization Sys (ADS) Accumulators. Util Will Replace ADS Check Valves W/Qualified Valves by 850629

ML20080Q515
Person / Time
Site:	FitzPatrick
Issue date:	02/17/1984
From:	Bayne J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK
To:	Vassallo D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.28, TASK-TM JPN-84-13, NUDOCS 8402240094
Download: ML20080Q515 (7)

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123 Main Street White Plains, Nev York 10601 914 681.6200

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& Authority February 17, 1984 JPN-84-13 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Mr. Domenic B. Vassallc, Chief Operating Reactors Branch No. 2 Division of Licensing

Subject:

James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 Qualification of ADS Accumulators NUREG-0737 Item II.K.3.28

References:

1. NRC lettcr, D. B. Vassallo to J. P. Bayne dated May ll, 1983.

Dear Sir:

Attachment I to this letter is our response to your May 11, 1983 request for additional information regarding ADS accumulator qualifications (Reference 1).

As. described in the attachment, We have not been able to confirm the original design requirements for certain check valves associated with the ADS accumulators. Therefore, the Authority will replace these valves with qualified valves by June 29, 1985 dependent on the availability of replacement valves.

If you require additional information, please contact J. A. Gray, Jr. of my staff.

Very truly yours ib[. bY J. P. Bayne d Executive Vice President Nuclear Generation cc: Office of the Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 136 Lycoming, New York 13093

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.* NEU YORK POWER AUTHORITY  !

JAMES A. FITZPATRICK NUCLEAR POWER PLANT  !

ATTACHMENT I to JPN-84-13 Response to NRC-5/11/83 request (Reference 5) for additional information regarding NUREG-0737 Item II.K.3.28, " Qualification of ADS' Accumulators."

Ql. When taking into account leakage, seismic events and a harsh environment, what is the length of time the accumulators are available to perform their function, both at. normal containment pressure and at-a specified percent (i.e., 70%) of drywell pressure following an accident? Does this meet the

[ requirements specified in the plant's FSAR?

Al. As described in our responses to Questions 5, 9 and 10, the Authority has conducted analyses of the ADS to consider seismically induced piping stresses and the environmental qualification of electrical and mechanical components.

Under normal environmental conditions and normal containment pressure, the ADS accumulators are capable of' performing their function for approximately 260 minutes (Leakage from the ADS is disdussed in our response to Questions 4 and 7). At seventy percent of. peak drywell pressure following an

. accident, the ADS accumulators are capable.cf performing their

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function.for approximately.200 minutes. Peak drywell pressure during a design basis event.is 45 psig. For pipe breaks resulting in drywell pressures greater than 70 percent of i- accident drywell pressure (31.5 psig), sufficient reactor depressurization occurs due to the break to preclude the need for. ADS (Reference 9). The accumulators are sized to provide two'actuations at a drywell pressure of 43.4 psig. .This is

, significantly higher than 31.5 psig. Therefore, the FitzPatrick design provides_an adequate short term capability to place the-reactor in the shutdown' cooling mode.

Q2. . Describe the ADS accumulator system design and operation (e.g., trains, air supply, capacity, alarms and

-instrumentation and their location, etc.).

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.A2. There are a-total of eleven safety relief valves at FitzPatrick including the seven ADS valves. (Tne mechanical design of these valves is described in Section 4.4 of the FSAR, Reference 6. This same section also describes the purpose of the ADS and it's operation. All eleven safety relief valves open on excess steam. pressure. In addition, each valve can.be opened manually from tLe control room.

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Seven of the eleven valves are opened by the ADS actuation logic. A remote' ADS control panel for manual control of the safety relief valves is provided so that the plant can be i placed in a cold shutdown-condition-in the event of a severe fire in the relay room, control room or cable room.

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Th0-ADS accumulator system consists of seven accumulators.

Each accumulator supplies a single ADS safety relief valve.

These accumulators are ASME Boiler & Pressure Vessel Code Section VIII tanks. The purpose of the ADS accumulators is to assure that safety relief valves can be opened and held open in the event of the loss of nitrogen supply.

The accumulator vessels were inspected for structural adequacy using nondestructive techniques . In addition, the tanks are designed and supported to withstand a design basis earthquake. (Supply piping and supports are addressed in our response to Question 9.) Eacn accumulator has a volume of approximately 226 cubic inches. Each accumulator is normally pressurized by the instrument air system which supplies nitrogen at approximately 110 pounds per square inch.

Nitrogen is supplied to the drywell instrument air lines from a nitrogen storage unit. The instrument. air lines are configured as a ring-header within the drywell. Approximately half of the ADS accumulators are supplied from each side of the ring-header. Tne line supplying the drywell ring-header is equipped with a low /nigh pressure alarm which indicates in the main control room. Similarly, loss of pneumatic pressure to the ADS is annunciated in the control room. Actuation of the ADS does not require any source of offsite power. Safety relief valves-use safety related DC power from the plant batteries for control wnile the accumulators supply pneumatic motive power.

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Q3, Define the basis for tne allowable leakage criteria for tne ADS accumulator system (e.g., boundary conditions, environmental, and seismic parameters, operator interface, margin, etc.).

A3. See response to Question No. 4.

Q4. What margin is in the allowable leakage criteria to account for possible increase in leakage resulting from the effects of a harsn environment and/or a seismic event.

A4. The ADS accumulators are sized to provide two actuations at 70% of maximum allowable drywell pressure (43.4 psig). This is based upon several factors:

a. Maximum allowable leakage past the eneck valves upstream of the accumulators is less than or equal to 0.12 SCFH.

This is the' acceptance criteria for the leak rate test of ADS pneumatic supply cneck valves. (In the single test conducted to date, the leakage rates typically seen are much less than the allowable).

b. . ADS accumulator are pressurized to normal system pressure (110 psig).

The Authority has analyzed tne ADS pnuematic supply system allowing variation in supply pressure, leak rates and drywell pressure. Results indicate t.:at operation of ADS is possible

. over a wide ranga of system initial pressures and drywell pressures. The tima period after loss of pneumatic supply for which ADS can be operated is dependent upon initial conditons and leak rates. The lower limit (based upon a leak rate of 0.12 SCFH) is 200 minutes assuming normal supply pressure is availaole before loss of pneumatic supply. If initial supply pressure is less than 110 psig, then approximately 2.5 minutes per psi difference below 110 psig is subtracted from the 200 minute limit. A supply pressure of 96 psig at 70% of maximum drywell pressure (43.4 psig) will permit two ADS actuations within 65 minutes of loss of pneumatic supply.

Q5. A statement that test and/or analysis performed verified that a harsh environment and/or seismic event would not increase the leakage rate.

AS. As stated in our response to Question No. 9, the seismic stress levels are on the order of one-tenth of the maximum allowable stress levels. Wnile no specific analysis or test has been performed to determine the susceptability of this system to seismically induced leaks, the Authority considers the low stress levels and high degree of structural integrity adequate to preclude any significant increases in leak rate.

The electrical components of the ADS accumulator system (relief valve pilot solenoid valves) have been qualified for a harsh environment as part of the Authority's environmental qualification program.

Q6. A statement that verifies that no credit was taken for non-safety related equipment and instrumentation when l establishing the allowable leakage criteria.

A6. The test procedure described in response no. 7 determines leakage from the ADS accumulator pressure boundary (including the upstream check valves, discharge solenoid valves, intervening pipe and fittings and accumulator.) All components comprising the accumulator pressure boundary are safety-grade components with the exception of tne two check valves installed in the pneumatic supply line to each accumulator. (Refer to our response to question no. 10 for further infc mation regarding these check valves.)

Q7.. Define the periodic leak testing of the ADS accumulator system (i.e., the time interval between these leak tests, along with a concise description of the test procedure employed).

A7. ADS accumulator system leak testing is performed as required; no specific test interval is currently in effect.

The test procedure employed determines the leakage rate of two soft-seated check valves (series arrangement) in the instrument air supply piping to each ADS Valve and accumulator. The leak rate of these check valves is determined by isolating the instrument air supply and measuring any drop in pressure at the pilot valve. After

allowing for a brief stabilization period, pressure decrease over a.30 minute interval is observed and recorded. Leak rate is then calculated based upon the observed pressure drop.

A concise description of tne surveillance performed, and how

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frequent, on alarms and instrumentation associated with the ADS accumulator system.

A8.- Section 4.5.D of the FitzPatrick Technical Specifications requires the following surveillance of tne ADS at least once per operating cycle:

1. A simulated automatic initiation which opens all pilot valves.

2. Manually open each relief / safety valve wnile bypassing steam to the condenser. Observe a ten percent (or greater) closure of the turbine bypass valves, to verify

-that the relief / safety valve has opened.

3. A' logic system functional test. (As defined in Section 1.F.6 of the FitzPatrick Technical Specifications a logic system functional test is a test of relays and contacts of a logic circuit from sensor to activated device to ensure components are operable per design intent. Where practicable, action will go to completion: i.e., pumps will be started and valves operated.)

A detailed description of the instrumentation and controls associated with the AUS can be found in (Reference 6) Section 7.4.3.3 of Revision 1 of the updated FitzPatrick FSAR.

09. A statement tnat confirms that the ADS accumulator system, associated equipment and control circuitry, are seismically qualified.

A9. In response to I.E. Bulletin No. 80-01 (Reference 3)

("Oparability of ADS Valve Pneumatic Supply"), the Authority reviewed the seismic capability of the pneumatic supply and accumulator system servicing the ADS valves. The existing techniques for the design-and construction of small bore piping insures that such piping, with its small mass and large flexibility, will withstand seismic events without damage.

Computer aided analysis is neither necessary or required.

Notwithstanding, the Authority has analyzed two of the seven systems. The results indicate that seismic stresses are less than one-tenth of the maximum allowable stress. Based on this analysis, the ADS pneumatic supply system from the accumulator isolation check valves to the ADS valve operators is seisaically adequate. The pneumatic supply ring header will be analyzed to determine its seismic adequacy.

The ADS accumulators are designed and supported to withstand design basis seismic events. ADS controls and instrumentation are designed as Class I seismic equipment.

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Q10. A statement that confirms that electrical and mechanical components of-the ADS accumulator system and associated equipment and control circuitry are environmentally qualified for conditions associated with normal operation, maintenence, testing, and postulated accidents.

A10. The FitzPatrick ADS accumulators were designed and fabricated to the requirements of ANSI B31.1. ANSI B31.1 invoked the requirements of ASME Section VIII for unfired pressure vessels. In addition, augmented quality assurance provisions were imposed on tne ADS accumulators to assure that the safety standards in effect at_the time of plant design for safety-related components were complied with. Specifically, mechanical properties and chemical composition were certified, material traceability was establisned, and nondestructive examinations (liquid penetrant and radiography) were conducted. Based upon tnis information, the ADS accumulators are adequate to perform their intended function.

As described in our Response to question No. 7, two check valves arranged in. series are installed in the pneumatic supply line to eacn ADS accumulator. The Autnority has not been able to confirm the environmental qualification of tnese valves. Tnerefore, tne Authority will replace these valves.

Additional information concerning the environmental qualifications of the ADS can be found in Section 7.4.3.3.5 of the updated FitzPatrick FSAR.

Qll. A statement verifying that the ADS valves, accumulators, associated equipment and instrumentation are capable of performing their function during and following an accident situation while taking no credit for non-safety related equipment and instrumentation.

All. The FitzPatrick Automatic Depressurization System is capable of performing its intended function during and following an accident situation while taking no credit for non-safety related equipment and instrumentation. Two check valves in the pneumatic supply line to each ADS accumulator will bereplaced because records to document the enivronmental qualification of the existing valves are not currently available.

References:

1. PASNY 4/1/82 letter, J.P. Bayne to D. B. Vassallo; (JPN-82-35) regarding NUREG-0737 Item II.K.3.28, Qualification of ADS Accumulators

2. PASNY 1/11/82 letter, J. P. Bayne to T. A. Ippolito, (JPN-82-7) regarding NUREG-0737 January 1, 1983 modification and submittals e ,

3. PASNY 1/18/80 letter, J. D. Leonard to B. H. Grier, (JAPP-80-053) regarding I. E. Bulletin No. 80-01 " Operability of ADS Valve Pneumatic Supply"

4. NYPA 6/9/83 letter, J. P. Bayne to D. B. Vassallo, (JPN-83-53) regarding NUREG-0737 Item II.K.3.28, Qualification of ADS Accumulator

5. NRC 5/11/83 letter, D. B. Vassallo to J. P. Banye regarding NUREG-0737 Item II.K.3.28, Qualification of ADS Accumulators

6. James A. FitzPatrick Nuclear Power Plant Updated Final Analysis Report (FSAR), Revision 1, dated July 1983.

7. PASNY 5/20/83 letter, J. P. Bayne to D. 3. Vassallo (JPN-83-45) regarding response to 10 CFR 50.49-Equipment Qualification.

8. NYPA 6/6/83 letter, J. P. Bayne to D. B. Vassallo (JPN-83-52)

. regarding safety evaluation - environmental qualification of safety related electrical equipment.

9. General Electric Report, "BWR ADS Pneumatic System-Comparison to NUREG-0737 Requirement II.K.3.28", NEDE-24956 dated August, 1981.

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