ML20213E238

Forwards Equipment Qualification Branch Sser Input Covering TMI Action Item II.K.3.28, Qualification of Accumulators on Automatic Depressurization Sys Valves

ML20213E238
Person / Time
Site:	Columbia
Issue date:	08/16/1982
From:	Johnston W Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
References
CON-WNP-0539, CON-WNP-539, TASK-2.K.3.28, TASK-TM NUDOCS 8209010026
Download: ML20213E238 (6)

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• bck'etFile EQB Rdg. h ie 3 G $N-AUG Docket fio.59-397 ME!!0RA!!DUM FOR: Thomas M. Novak, Assistant Director for Licensing Division of Licensing FROM: William V. Johnston, Assistant Director Materials and Qualification Engineering Division of Engineering

SUBJECT:

WASHINGTON PUBLIC P0tlER SUPPLY SYSTEM (WPPSS) NUCLEAR PROJECT NO. 2 (WNP-2) INPUT TO THE SUPPLEMEtiTAL SAFETY EVALUATION REPORT II.K.3.28 - QUALIFICATION ADS ACCUMULATORS Plant Name: llPPSS Nuclear Project No. 2 (tlNP-2)

Docket No.: 50-397 Licensing Stage: NTOL Responsible Branch: Licensing Branch No. 2 Responsible Project Manager: R. Auluck Review Status: Confirmatory The enclosed Supplemental Safety Evaluation Report (SSER) was prepared by DE:M&QE, Equipment Qualification Branch. The reviewer is M. Haughey.

This input covers TMI Action Item II.K.3.28 - Qualification of Accumulators on ADS valves. '

The attached input discusses surveillance requirements to be included in the

!1NP-2 Technical Specifications. In discussions with P.. Bottimore of LGB it was indicated the surveillance of the low pressure alarm system would probably be included in-the standard Technical Specifications for WNP-2. However, as the specifications are not yet complete the inclusion of the surveillance re-quirements could not yet be confirmed. The daily surveillance of the bottle bank is not included in the standard technical specification but should be included because of the uniqueness of the WNP-2 system. Pressure alarms for this system are located downstream of the pressure reducers and therefore do not indicate inventory until the system is nearly depleted. The confirmation of the inclusion of the surveillance requirements in the technical specifications is the only incomplete area of this review.

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Nuclear Project No. 2 (WNP-2)

Supplementary Safety Evaluation Report (SSER) Input Equipment Qualification Branch II.K.3.28 Verify Qualification of Accumulators on Automatic Depressurization System Valves Reauirement Safety analysis reports claim that air or nitrogen accumulators for the automatic depressurization system (ADS) valves are provided with sufficient capacity to cycle the valves open five times at design pressures. GE has also stated that the emergency core cooling (ECC) systems are designed to withstand a hostile environment and still perform their function for 100 days following an accident. Licensees and applicants must demonstrate that the ADS valves, accumulators, and associated equipment and instrumentation meet these requirements and are capable of performing their functions during and following exposure to hostile environments, taking no credit for non-safety-related equipment or instrumentation. Ad-ditionally, air (or nitrogen) leakage through valves must be accounted for in order to assure that enough inventory of compressed air is available to cycle the ADS valves. If this cannot be demonstrated, it must be shown that the accumulator design is still acceptable.

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System Description

I Seven of the eighteen safety / relief / valves (SRV's) serve the ADS function if required. In addition to individual accumulators on each of these valves, two independent nitrogen bottle bank sub-j systems deliver pressurized nitrogen to the SRV's serving the ADS l function.

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9 The nitrogen banks are sized to provide a 30-day supply of nitrogen for the ADS function. In addition, two remote nitrogen connections are provided (one for each bank) to allow supplementing of the 30-day supply to ensure the ADS function is operable indefinitely during isolation of the compressor loop (normal air supply). The remote connections are located outside the reactor building to ensure access during post accident conditions. The nitrogen bottle bank supply consists of one bank of 15 bottles supplying nitrogen for three ADS SRV's and second bank of-19 bottles supplying the remaining four ADS SRV's.

The nitrogen bottles are located in the railroad lock of the reactor building to facilitate access. Under normal operating conditions, the controlled leakage boundary of the Reactor Building is maintained above the railroad lock so access is available to the bottles for recharging if required. The bottles are standard commercially available units pressurized to 2490 psig.

Each bottle has a capacity of 257 SCF. The bottles are mounted in accordance with Seismic Category I, Quality Class I requirements.

The required quantity of bottles was based on providing a 30-day air supply to the ADS valves to satisfy the long-term post-LOCA i demand based on the following:

l System ADS Cycles N2 Bank N2 Supply Leakage Allowed A (3 valves) 3855 SCF 2880 SCF 48 B (4 valves) 4883 SCF 3600 SCF 48 1

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In a letter submitted by the applicant on July 1, 1982 the licensee agreed to perform daily surveillance of each of the independent nitrogen supply bottles. This action should provide adequate warning of a significant bottle leak. If a leak is detected in any one of the bottles it is to be replaced. If the leak is of sufficient magnitude to cause the bottle bank to become ex-hausted the ADS valves associated with that bank will be considered inoperable as defined in Technical Specification 3.5.1.

I Evaluation The ADS backup air supply system has been designed for sufficient inventory to cycle the ADS valves in the event they are required to operate. The backup supply bottle banks will have daily surveillance to assure the bottles are not leaking and losing

nitrogen pressure. In addition to the daily surveillance of the system the following surveillance requirements should be performed in order to verify the bottle bank system will be actuated in the event of a loss of the normal air supply. This surveillance require-ment should be incorporated in the plant technical specifications.

Each ADS air supply system shall be determined operable (unless reactor pressure is less than 125 psig) by:

a.) At least once per 31 days, performing a ' CHANNEL FUNCTIONAL TEST of the accumulator backup compressed gas system low pressure alarm system.

b.) At least orce per 18 months, performing a CHANNEL CALI-BRATION of the accumulator backup compressed gas system j low pressure alarm systems and verifying an alarm setpoint I

of (135 psig) + (3 psig) on decreasing pressure.

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c.) At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> verifying the pressure in each of the bottles on the accumulator backup compressed gas system bottle bank is pressurized to at least 2200 psig.

d.) At least once per 18 months performing a calibration of the accumulator backup compressed gas system bottle bank pressure gages on each of the bottles.

The periodic surveillance of the low pressure alarm system in conjunction with the daily surveillance of the backup air supply bottle bank should assure an adequate and operable backup air supply to the ADS valves in the event they are required to operate.

The pneumatic supply systems and surveillance requirements for the technical specification have been discussed with the Reactor Systems Branch (RSB) of the NRC. RSB has the responsibility of reviewing the adequacy of the number of actuations of the ADS SRV valves for which the system is designed and qualified.

The EQB staff concludes the ADS air supply backup systems in conjunction with the discussed surveillance requirements should be adequate to assure a long-term air supply as required for the ADS SRV valves.

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