ML20126F812

Safety Evaluation Accepting Facility Design W/Respect to RG 1.97

ML20126F812
Person / Time
Site:	Pilgrim
Issue date:	12/23/1992
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20126F801	List: ML20126F798 ML20126F812
References
RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9212310147
Download: ML20126F812 (4)

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1. + ^o UNITED STATES 8' t. NUCLEAR REGULATORY COMMISSION

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WASHINGTON, D. C. 20555

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO FACILITY OPERATING LICENSE NO. DPR-35 BOSTON EDIS0N COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293 1.0 INTRODUCTIOf]

We completed our review of the licensee's conformance to Regulatory Guide (R.G.) 1.97, Revision 3, by providing our safety evaluation report (SER) to the licensee, on March 13, 1991. We found the licensee's design acceptable with respect to conformance to R.G.1.97, except for certain aspects of redundancy, separation, interfaces, channel availability, quality assurance, and servicing, testing, and calibration. By letters dated May 13, 1991, October 4, 1991, and February 28, 1992, the licensee requested that we reevaluate these issues. The licensee also identified new deviations for primary containment pressure - suppression pool, effluent radioactivity -

turbine building noble gases, emergency ventilation damper position, common plant vent noble gases and vent flow rates, and status of standby power.

2.0 EVALVATION We reviewed the licensee's submittals and concluded that the licensee either conforms to, or has adequately justified deviations from the guidance of R.G. 1.97, for: a) redundancy and separation, b) interfaces, c) channel availability, quality assurance, and servicing, testing, and calibration, and the post-accident monitoring. instrumentation for d) primary containment pressure - suppression pool, e) effluent radioactivity - turbine building noble gases, f) emergency ventilation damper position, g) common plant vent noble gases and vent flow rates, and h) status of standby pwer, a) R.G. 1.97 recommends that redundant or diverse channels should be electrically independent and physically separated from each other and from equipment not classified important to safety in accordance with R.G. 1.75.

In our SER we found that the licensee's separation criteria is a good faith attempt (as defined in NUREG-0737, Supplement No. 1, Section 3.7) to meet the NRC requirements for existing instrumentation. However, wie were concernd with redundancy and separation of future modifications.

The licensee stated that the guidance of R.G. 1.75 will be followed, for future modifications, except as documented. Based on the licensee's design basis and existing separation criteria, these documented exceptions to R.G.

1.75 are considered a good faith attempt to meet the NRC requirements, for future modifications. Therefore, the licensee's separation criteria is t

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4 b) R.G.1.97 recommends the use of qualified isolation devices wherever Category 1 or Category 2 instrumentation interfaces with instrumentation or control circuits that have less stringent design criteria. The licensee had not provided sufficient information for us to conclude that qualified isolation devices are used to protect Category 1 and Category 2 instrumentation. The licensee has described the electrical isolation methods used for interfaces of Category 1 and Category 2 instrumentation.

We find the licensee's isolation methods acceptable, c) R.G.1.97 recommends that channel availability, quality assurance, and servicing, testing, and calibration be in accordance with specified documents. The licensee stated that these issues were still under review.

Therefore, in our SER, we were unable to conclude that the licensee was in conformance with R.G. 1.97 for channel availability, quality assurance, or servicing, testing, and calibration.

These issues were reviewed as part of the NRC's R.G. 1.97 inspection. As reported in Inspection Report 50-293/92-06, dated June 23, 1992, the inspectors found some irregularities in the licensee's calibration program.

The licensee agreed to modify the R.G.1.97 calibration procedures. The inspection report, which is based on an audit of sample R.G. 1.97 instrumentation, did not include any irregularities in channel availability oc quality assurance. We assume that the channel availability, quality assurance, and servicing, testing, and calibration of other R.G. 1.97 instrumentation is similar to those inspected. Therefo m , based on the inspection report and the licensee's commitments, chanr. ' availability, quality assurance, and servicing, testing, and calibration are acceptable, d) The licensee has determined that primary containment pressure - suppression pool is a Type A variable. As a Type A variable this instrumentation should meet the Category 1 criteria. The licensee has described a deviation from the -5 psig to 4 times the design pressure (224 psig) range recommended by R.G. 1.97. The range of the installed instrumentation is 0 to 100 psig. The licensee's Emergency Operating Procedures (EOPs) require the operators to take actions to prevent a breach of primary containment based on specific suppression pool pressure within the provided instrument range. Specifically, the E0Ps require emergency suppression pool venting prior to reaching the suppression pool design pressure of 56 psig. Since the operator is required to take manual action prior to exceeding the suppression pool design pressure, the licensee's primary containment pressure - suppression pool range is acceptable, e) R.G.1.97 recommends Category 2 instrumentation to monitor effiuent radioactivity - noble gases from buildings or areas in direct contact with the primary containment where penetrations or hatches are located. The instrumentation provided by the licensee meets Category 3 criteria in lieu of Category 2 criteria.

The licensee has installed a high range effluent monitor on the operating floor of the turbine building to provide diagnostic and backup information to monitor potential leakage of radioactive effluent from the turbine building basement, up through the turbine building roof exhaust. The turbine building operating floor is not in direct contact with the primary containment or exhaust from any system containing potential fission product releases. Under normal operating conditions the area below the operating floor is kept at a negative pressure and any release from the turbine building basement area and ground floor is routed out the reactor building vent and is monitored by the reactor building vent instrumentation. During a design basis event with a loss of offsite power this negative pressure below the turbine operating level would be lost; therefore, there is potein.ial for some radioactive effluent to escape via the turbine building roof even thought the turbine building roof exhaust fans would not be operating. For this event the licensee installed the existing turbine building effluent radioactivity instrumentation to provide diagnostic information and to provide backup information. Based on the above information, Category 3 turbine building effluent radioactivity - noble gases instrumentation is acceptable.

f) R.G. 1.97 recommends Category 2 emergency ventilation damper position instrumentation to monitor the operation of emergency ventilation systems.

The licensee's standby gas treatment (SBGT) system damoer position instrumentation is not environmentally qualified. In lieu of environmentally qualifying this instrumentation, the licensee has proposed the use of Category 2 SBGT exhaust flow in conjunction with reactor building isolation control (RBIC) and control room environmental control (CREC) systems damper position instrumentation to provide status information for the SBGT. The use of the RBIC and CREC damper positions and SBGT exhaust flow instrumentation in conjunction with Category 3 SBGT damper position instrumentation is acceptable, g) R.G.1.97 recommends Category 2 monitoring of noble gases and vent flow rates through the common plant vent to allow continuous assessment of the magnitude of post-accident radiological releases to the onvironment. The licensee has control room indication of the high range instrumentation.

However, the normal operating range instrumentation is located near'the top of the main stack and is indicated locally at the main stack. Therefore, the licensee has not included the normal range instrumentation in the R.G.

1.97 program.

Because the normal range information is not indicated in the control room, and would not be immediately available, the flow rate past the normal range monitor is estimated by the Emergency Dose Assessment Program based on the number of stack dilution and standby gas treatment system fans operating.

Based on the above information, the use of local normal operating range noble gases vent flow rate instrumentation is acceptable.

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_4 h) R.G. 1.97 recommends the use of plant specific Category 2 status of standby power instrumentation to monitor power supply system status. The licensee has revised the listing of status of standby power instrumentation. Since this instrumentation is plant specific and the licensee has provided adequate justification for the changes, we find the licensee's status of standby power instrumentation acceptable.

The licensee's submittals also included several other updates to their post-accident monitoring instrumentation. We have reviewed these changes and consider them minor or editorial in nature. Therefore, since these changes do not change the acceptability of the instrumentation they are acceptable. -

3.0 CONCLUSION

Based on our review of the licensee's submittals, we find the Pilgrim Nuclear Power Station design acceptable with respect to conformance to R.G. 1.97, Revision 3.

Principal Contributor: B. Marcus Date: December 23, 1992 mm.m.m.m.... -.. ._ -