ML20199B292
| ML20199B292 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/06/1997 |
| From: | Hannon J NRC (Affiliation Not Assigned) |
| To: | Richard Anderson NORTHERN STATES POWER CO. |
| References | |
| TAC-M95128, TAC-M95129, NUDOCS 9711180264 | |
| Download: ML20199B292 (3) | |
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l November 6, 1997 Mr. Roger O. Anderson, Director Nuclear Energy Engineering Northem States Power Compt.1y 414 Nicollet Mall Minneapolis, Minnesota 55401
SUBJECT:
PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT NOS.1 AND 2 -
REQUEST FOR RELIEF FROM CODE REQUIREMENTS FOR BLOCK VALVES IN SERIES WITH OVERPRESSURE PROTECTION DEVICES (TAC NOS. M95128 AND M95129)-
Dear Mr. Anderson:
In a letter dated December 27,1995, Northern States Ponr Company (NSP) requested permanent relief from Articles 122.6.1 and 122.6.2(a) of the United States of America Standards (USAS) B31.1 1967 Power Piping Code (B31.1 Code). The relief would allow NSP to permanently retain the installation of several manual stop (block) valves located in series with overpressure protection relief devices in the residual heat removal system (RHRS) and.
cherrical volume control system (CVCS) and use soecific administrative controls to verify their positions at Prairie Island Nuclear Generating Plant, Units 1 and 2. The NRC staff has determined that authorization of an attemative or granting a relief from B31.1 Code design provisions is unnecessary and inappropilate for piping systems that are not part of the reactor cooiant pressure boundary (RCPB) for Prairie Island Units 1 and 2.
NSP requested that the staff authorize the installed valve configurations at Prairie Island Units 1 and 2 as an alternative to B31.1 Code design requirements stated in Articles 122.6.1 and 122.6.2(a) pursuant to 10 CFR 50.55a(a)(3). The attemative is based on administrative controls currently in place that ensure the block valves remain in the open position. Since the block valves facilitate certain test and maintenance activities and any consideration to remove the block valves would result in significant cost, and since compliance with the B31.1 Code requirements would result in increased difficulties associated with testing and maintenance without a compensating increase in the level of quality and safety, NSP requested relief pursuant to 10 CFR 50.55a(a)(3).
The NRC staff has reviewed NSP's request for the staff to authoriI:e the proposed attemative to B31.1 Code requirements pursuant to 10 CFR 50.55a(a)(3). However, the staff finds that 10 CFR 50.55a(a)(3) applies to proposed attematives to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section :ll and Section XI, requirements and not to B31.1 design provisions. Accordingly, authorization of an attemative to B31.1 Code design requirements pursuant to 10 CFR 50.55a(a)(3) is unnecessary and inappropriate for Prairie Island Units 1 and 2.
In its final safety analysis report, NSP committed to design Prairie Island Units 1 and 2 in acco:Jance with USAS B31.1-1967 Code design provisions. The portions of the RHRS and CVCS were constructed to the requirements of the 1968 Eddon of the ASME Code, Section 111.
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, R. O. Andersen November 6, 1997 in NSP's December 27,1995, lett:r, s;v;r:I m:nu:1 block vriv;s installed in Prciria Isl:nd Units 1 and 2 were identified that did not meet the design requirements of B31.1 Code.
Articles 122.6.1 and 122.6.2(a). The NRC staff views NSP's discovered condition of noncompliance with the B31.1 Code design provisions as evidence that NSP is not in conformance with its final safety analysis report (FSAR). Therefore, NSP must either come into conformance with the FSAR, or incorporate this condition into the approved facility design and '
revise the FSAR, as appropriate, if NSP chooses the latter option, it should ensure that the C
provisions of 10 CFR 50.59 are satisfied.
-NSP stated that an evaluation was conducted in accordance with 10 CFR 50.59. The RHRS
. manual valves are RH-7-1 and 2RH-7-1, which are located in the discharge path of spring-loaded check valves RH-6-1 and 2RH-6-1. The spring-loaded check valves provide overpressure protection to the discharge portion of one train of RHR when the system is split into separate trains, and when the trains are cross connected, relief valves SI-26-1 and 2SI-26-1 (which are not isolable) protect both trains. The CVCS manual valves are VC-16-3 and 2VC-16-3. These block valves are installed in identical configurations in each unit. The valves are located in the supply path to spring-loaded check valves VC-17-1 and 2VC-17-1, t
respectively. VC-17-1 and 2VC-17-1 provide two functions. The valves provide thermal relief protection for the charging pump line between the regenerative heat exchanger discharge flow control valve and the upstream check valve should the line become ir. 'ated with normal letdown still in operation. Additionally, the valves provide bypass flow around the flow control valve should the valve shut with the pumps running. The evaluation concluded that no safety concern would originate as a result of inadvertent closure of valves RH 7-1,2RH-7-1, VC-17-1, and 2VC-17-1.
The staff concludes that authorization of an attemative or relief from B31.1 Code design provisions is unnecessary and inappropriate for piping systems not part of the RCPB at Prairie Island Units 1 and 2. The staff notes that the "no safety concern" conclusion by NSP is not appropriate for determining whether the change constitutes a change to the technical specifications or otherwise is an unreviewed safety question. NSP should evaluate the change against the criteria in 10 CFR 50.59 to determine whether a license amendment reflecting the change is necessary. Should you have questions concerning this determination, please contact Beth Wetzel at 301-415-1355.
Sincerely, ORIGINAL SIGNED BY Kevin A. Connaughton John N. Hannon, Director Project Directorate 111-1 Division of Reactor Projects - till'V Office of Nuclear Reactor Regulation Docket Nos 50-282 and 50-306 cc:
See next page DISTRIBUTION:
Docket File (50-282 and 50-306)
PD#31 Reading PUBLIC E. Adensam (EGA)
OGC ACRS J. McCormick-Barger, Region lli D. Terao DOCUMENT NAME: G:\\WPDOCS\\ PRAIRIE \\Pl95128.RR *See previous concurrence v.
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10/14 /97 11/ 3 /97 11/ 6 /97 OFFICIAL RECORD COPY 4
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- e-y Mr.' Roger O. Anderson, Director -
Prairie Island Nuclear Generating ?
Northem_ States Power Company _
Plant
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J. Ei Silberg, Esquire
- Site Licensing i
Shaw, Pittman, Potts and Trowbridge Prairie Island Nuclear Generating 2300 N Street, N. W.-
Plant
' Washington DC 20037--
Northem States Power Company j
- 1717 Wakonade Drive East i
Plant is,snager =...
Welch, Minnesota 55089 i
Prairie Island Nuclear Generating
- Plant.
Tribal Council -
Northem States Power Company Prairie Island Indian Community 1717 Wakonado Drive East-
-ATTNF Environmental Departme'.i i
Welch, Minnesota 55089 5636 Sturgeon Lake Road Welch, Minnesota 55089 Adonis A. Nebiett -
- Assistar,t Attomey General ONice of the Attomey General
- 455 Minnesota Street--
Suite 900 -
St.' Paul, Minnesota 55101 2127 i
1 U.S. Nuclear Regulatory Commission Resident inspector's O# ice y;
.1719 Wakonade Drive East i
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Welch, Minnesota 55089-9642 1
' Regional Administrator, Region 111 U.S. Nuclear Regulatory Commission
' 801 Warrenville Road.
Lisle, Illinois 60532 4351 t
1:
I Mr. Je# Cole, Auditor / Treasurer L
Goodhue County Courthouse Box 408 i~
_ Red Wing, Minnesota 55066-0408 l
. Kris Sanda, Commissioner -
Department of Public Service 121 Seventh Place East l
Suite 200 L
.St. Paul, Minnesota 55101-2145 l
November 1996
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