ML20214U363

Submits Results of Review of Mod to RHR Sys HX Inlet Temp Sensor,Per 851127 Request.Drawing Showing Termination of Wire Leader Details & Use of Fiber Optic Cable Acceptable

ML20214U363
Person / Time
Site:	Prairie Island
Issue date:	06/01/1987
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Musolf D NORTHERN STATES POWER CO.
References
NUDOCS 8706110158
Download: ML20214U363 (4)

Text

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JUN 011987 Docket hos. 50-282 and 50--306 Mr. D. M. Musolf, Manager Nuclear Support Services Northern States Power Company 414 Nicollet Mall Midland Square, 4th Floor Minneapolis, Minnesota 55401

SUBJECT:

MODIFICATION OF RESIDUAL HEAT REMOVAL SYSTEM (RHR) HEAT EXCHANGER INLET TEMPERATURE SENSOR AND CLARIFICATION TO FIBER OPTIC CABLE ISOLATION By letter dated November 27, 1985, Northern States Power Company requested that the NRC review a deviation to a modification that was previously agreed to as described in our Safety Esaluation issued by letter dated October 18,1985 for the Prairie Island Nuclear Generating Plant, Unit Nos. I and 2. The Safety Evaluation was based on the temperature detector being installed in the inlet piping of the RHR heat exchanger. As an alternative, by letter dated Noveniber 27, 1985, you proposed to install an environmentally qualified temperature detector on the lower containment wall directly above the RHR recirculating sump. You also submitted clarifying information dealing with the construction of the floer optic cables. The purpose of this letter is to give the results of our reviews regarding these two issues.

1 The Prairie Island Nuclear Generating Plant, Unit Nos. I and 2, is designed such that inlet temperature to the RHR heat exchanger would be known to the i operator from water temperature coming from all sources (i.e., loop hot legs l and Refueling Water Storage Tank) except during the recirculation phase when '

the water entering the RHR heat exchanger comes from the containment sump. In a telephonic conference held on May 13, 1987, you indicated that the temperature detector proposed to be installed on the lower containment wall directly above the RHR recirculating sump would be submerged during the recirculation mode following the postulated design basis accident. On this basis, we agree with you that locating the temperature sensor inside containment in the area of the sump, would result in meeting the intent of the requirements of Regulatory Guide 1.97, Revision 2, since, when this modification is in place, the inlet temperature of the RHR heat exchanger can be monitored during all phases of a postulated accident. Therefore, we find your proposed deviation in locating 0706110158 870601 i PDR ADOCK 05000282 >

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> the temperature detector from the inlet pipe of the RHR heat exchanger to the vicinity of the containment sump acceptable.

The staff also completed review of the information dealing with the construction of the fiber optic cable and the cable termination. Your drawing showing the termination of the wire leader details is found acceptable.

Based on our review, we find the use of the fiber optic cable at the Prairie Island Nuclear Generating Plant, Unit Nos. I and 2, is acceptable.

We consider that all issues raised in your letter dated November 27, 1985, have been addressed with the completion of our review of the alternative location of the temperature sensor for measuring the temperature inlet of the RHR heat exchanger and the design of the fiber optic cable.

Sincerely, Cuwrud e1pae6 ty 3C;7&p FA. 6Mahenttela Dennis M. Crutchfield, Director Division of Reactor Projects, III, IV, V

& Special Projects '

Office of Nuclear Reactor Regulation cc: See next page

• SEE PREVIOUS CONCURRENCE i

Office: LA/PDIII-3 PM/PDIII-3 PD/PDIII-3 ICSB Surname: *PKreutzer- *DDilanni/tg *DWigginton *JMauck Date: 05/19/87 05/19/87 05/28/87 05/28/87 Office: HF AD/RP D Surname: *SHWeiss *GHolahai. D d Date: 05/28/87 05/28/87 /j /87

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Mr. D. M. Musolf Prairie Island Nuclear Generating Northern States Power Company Plant cc:

Gerald Charnoff, Esq.

Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.

Washington, DC 20037 Dr. J. W. Ferman Minnesota Pollution Control Agency 520 Lafayette Road St. Paul, MN 55155 Mr. E. L. Watzl, Plant Manager Prairie Island Nuclear Generating Plant Northern States Power Cor..'ny Route 2 Welch, Minnesota 55089 Jocelyn F. Olson, Esq.

Special Assistant Attorney General Minnesota Pollution Control Agency 1935 W. County Road, B2 Roseville, Minnesota 55113 U.S. Nuclear Regulatory Ccmission Resident Inspector's Office 1719 Wakonade Drive East Welch, Minnesota 55089 Regional Administrator, Region III U.S. Nuclear Regulatcry Comission '

Office of Executive Director for Operations 799 Roosevelt Road l Glen Ellyn, Illinois 60137 l

Mr. William Miller, Auditor Goodhue County Courthouse Red Wing, Minnesota 55066 j

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