ML20204H713

Safety Evaluation Concluding That NNECO Provided Adequate Justification for Deviations from RG 1.97,Rev 2, Recommendations,For Instrumentation Monitoring CST Level & Containment Area Radiation at Mnps Unit 2

ML20204H713
Person / Time
Site:	Millstone
Issue date:	03/17/1999
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20204H673	List: ML20204H668 ML20204H713
References
RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9903290136
Download: ML20204H713 (2)

Text

-

. no neoug k UNITED STATES s :s j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. asses-4001

\;.ca)...

EMETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

, RELATED TO DEVIATION FROM REGULATORY GUIDE 1.97. REVISION 2 FOR FACILITY OPERATING LICENSE NO. DPR-85 NORTHEAST NUCLEAR ENERGY COMPANY THE CONNECTICUT LIGHT AND POWER COMPANY THE WESTERN MASSACHUSETTELELECTRIC COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 2 DOCKET NO. 50-336

1.0 INTRODUCTION

On November 22,1989, the staff issued a Safety Evaluation (SE) regarding Northeast Nuclear Energy Company's conformance to Regulatory Guide (RG) 1.97 " Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident," Revision 2, for the Millstone Nuclear Power Station, Unit 2. In submittals dated January 12 and 25,1999, the licensee requested approval of deviations from RG 1.97 recommendations for the instrumentation that monitors CST level and containment area radiation.

2.0 EVALUATION 2.1 CST LevelInstrumentation RG 1.97 recommends Category 1 CST level instrumentation to monitor the primary source of water for auxiliary feedwater, in a submittal dated April 4,1984, the licensee indicated that the CST level instrumentation did not meet the RG 1.97 Category 1 criteria. This instrumentation consists of an electronic an( a pneumatic loop. In the April 4,1984, submittal the licensee committed to upgrade the electronic loop and to retain the pneumatic loop as is, but maintain it as Category 1. By letter dated August 8,1986, the li::ensee stated that the electronic loop has alarms and continuous indication in the control room. The pneumatic level controller has local indication and high- and low level alarms in the control room. Both the electronic and pneumatic instrument loops are located in a mild environment. By letter dated June 15,1987, the licensee informed the staff that the electronic loop had been upgraded.

' ~

Enclosure 9903290136 990317 PDR ADOCK 05000336 P PDR

1

^

O \

• - 2-In the licensee's January 12,1999, letter a level indicating switch with local indication and control room alarm was identified as an additional diverse measurement of CST level. This local indication is mechanical, requires no electrical power, is located in a mild environment, and is accessible at all times. Additionally, an electrical contact is provided for a low-level alarm in the control room.

Although the instrumentation supplied by the licensee does not fully meet the Category 1 criteria, the instrumentation provides reliable and diverse indication of the CST level and is, therefore, acceptable.

2.2 Containment Area Radiation instrumentation RG 1.97 recommends Category 2 containrnent area radiation instrumentation for detection of breach of barriers to fission products and Category 1 containment area radiation instrumentation -

for detection of significant releases. Revision 2 of RG 1.97 recommends that the detectors respond to gamma radiation photons within any energy range from 60 kev to 3 MeV with an energy response accuracy of *20 percent at any specific photon energy from 0.1 MeV to 3 MeV and overall system accuracy within a factor of two over the entire range. However, Revision 3 of RG 1.97 recommends that the detectors respond to gamma radiation photons within any energy range from 60 kev to 3 MeV with a dose rate response accuracy within a factor of two over the entire range. The licensee's instrumentation does not meet the Revision 2 securacy recommendations, but does meet the Revision 3 accuracy recommendations. Since the licensee's containment area radiation instrumentation meets the Revision 3 recommendations, the instrumentation that monitors containment area radiation is acceptable.

3.0 CONCLUSION

Based on review of the licensee's submittals, the staff finds that the licensee has provided adequate justification for deviations from RG 1.97, Revision 2 recommendations, for the instrumentation that monitors CST level and containment area radiation at the Millstone Nuclear Power Station, Unit 2. Therefore, the staff concludes that the licensee's CST level and containment area radiation post-accident monitoring instrumentation is acceptable.

Principal Contributor: B. Marcus Date : March 17, 1999

, v - n ,gw-': -

+r -

'- -