ML19211A683

Notifies That Util Will Be in Compliance by 800131 W/Lessons Learned Task Force Recommendations Re Relief & Safety Valves Direct Position Indication & Inadequate Core Cooling Detection Instrumentation

ML19211A683
Person / Time
Site:	Prairie Island
Issue date:	12/14/1979
From:	Mayer L NORTHERN STATES POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
RTR-NUREG-0578, RTR-NUREG-578 TAC-12428, TAC-12429, NUDOCS 7912200432
Download: ML19211A683 (2)

Text

6 NSP NORTNERN STATES POWER COMPANY M IN N E A r*O L.l S. M IN N E S OTA 5 5 408 December 14, 1979 Director of. Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket No. 50-282 License No. DPR-42 50-306 DPR-60 Lessons Learned Implementation References (1) Letter, L 0 Mayer (NSP) to Director of Nuclear Reactor Regulation (NRC), dated November 20, 1979 (2) Letter, H Denton (NRC) to L 0 Mayer (NSP) dated October 30, 1979 Pursuant to submittal of Reference (1) and verbal discussions with M Grotenhuis, NRC Project Manager, Northern States Power has conducted additional reviews to determine compliance status with the Lessons Learned Implemencation Requirements identified in Reference (2).

In keference (1), NSP had identified three items as not fully meeting NRC requirements by the January 1, 1980 date; i.e. Items 2.1.3.a, 2.1.3.b, ar.d 2.1.8.a.

Further reviews and clarification of the lessons learned short term require-ments show that the Prairie Island Nuclear Generating Plant will be in compliance by January 31, 1980 as described below for these identified items.

2.1.3.a Direct Position Indication - Relief and Safety Valves For the pressurizer safety valves, acoustic monitors have been installed on Unit 1 during a recent outage and will be installed on Unit 2 during the forthcoming outage. These devices will be operational by January 31, 1980. The additional time required ,

involves building and installation of instrumentation racks, routing cables, and meter installation in the control room.

1634 077 7 912200 M L

, NORTHERN STATES POWER COMPANY December 14, 1979 Page For the pressurizer power ' operated relief valves, qualified limit switches are installed on Unit 1 for the closed indication.

According to clarification 5 of Reference (2), the position indication should be environmentally qualified. Though this is a recommendation, not a requirement, we have ordered environmentally qualified limit switches to assure both open and closed indication will be satisfactory. The NUREG-0578 discussion for Item 2.1.3.a points out that closed indication is of most concern. We expect to receive the limit switches in January and will install these prior to January 31, 1980 on Unit 2. A special outage would be required for Unit 1 for modification of the cpen limit switches and is not planned.

2.1.3.b Instrumentation for Detection of Inadequate Core Cooling-Subcooling Meter The subcooling meters are due to be received about December 21, 1979.

On both units modification will be completed by January 31, 1980.

The subcooling indication will be provided 'from multiple incore exit thermocouples and redundant system pressure nensors. Clarifica-tion 4 of Reference (2) states " Redundant safety 1;rade sy9 tem pressure measures should be provided". Since thin :s a recommenda-tion, not a requirement, this system is acceptable. However, we do intend to upgrade the pressure sensors to safety grade in the long term ir required by the R.G.I.97 revision.

A continuous display of subcooling indication will be provided by two meters on the control board. The calculational devices will be safety grade. Appropriate steps will be provided to assure no adverse ef fect on the reactor protection or ESF systems for this modification.

2.1.8.a Improved Post-Accident Sampling Capability - RCS Hydrogen Based on further review, the requirement for RCS hydrogen analysis can be met by January 1,1980. The technique will utilize our plant interim sampling equipment (external handling gear and shielding) plus addition of a dilution procedure which will assure that samples for hydrogen analysis can be properly handled and analyzed without incurring excessive radiation exposure.

Thus, the Prairie Island Plant will be implementing all NRC Staf f Category A requirements by January 31, 1980 or be shutdown by January 31,1980 and not restart before completion of that implementation.

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L 0 Mayer, PE Manager of Nuclear Support Services LOM/jh 1634 078 cc J G Keppler G Charnoff