[Federal Register Volume 60, Number 46 (Thursday, March 9, 1995)]
[Notices]
[Pages 12990-12991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-5773]



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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-282 and 50-306]


Exemption

    In the Matter of Northern States Power Co. (Prairie Island Units 
1 and 2)

I

    Northern States Power Company (NSP, the licensee) is the holder of 
Facility Operating Licenses Nos. DPR-42 and DPR-60 which authorize 
operation of Prairie Island Nuclear Generating Plant, Unit Nos. 1 and 
2. The units are pressurized water reactors (PWR) located in Goodhue 
County, Minnesota. The licenses provide, among other things, that the 
facilities are subject to all rules, regulations, and orders of the 
Nuclear Regulatory Commission (the Commission) now or hereafter in 
effect.

II

    Pursuant to 10 CFR 50.12(a), the NRC may grant exemptions from the 
requirements of the regulations (1) which are authorized by law, will 
not present an undue risk to the public health and safety, and are 
consistent with the common defense and security; and (2) where special 
circumstances are present.
    Section III.G.1 of Appendix R to 10 CFR part 50 requires, in part, 
that fire protection features shall be provided for structures, 
systems, and components important to safe shutdown so that one train of 
systems necessary to achieve and maintain hot shutdown conditions be 
free of fire damage. The staff has interpreted these provisions as 
requiring that features shall be such that one train of safe shutdown 
systems remains operable, notwithstanding a fire or consequences 
therefrom, without one having to perform any repair. In this context, 
the staff considers manually pulling fuses to isolate certain systems 
as a repair. Accordingly, the staff interprets Section III.G.1 of 
Appendix R as not permitting the pulling of fuses in order to be in 
compliance.
    By letter dated May 2, 1994, the licensee requested an exemption to 
permit it to manually remove fuses from the power-operated relief valve 
control circuit in the event of a fire, in lieu of modifying plant 
hardware which would otherwise be required to achieve compliance with 
Section III.G.1 of Appendix R. The licensee's submittal initially 
referenced Section III.G.2 of Appendix R as providing the requirements 
from which the licensee was seeking an exemption, but in a follow-up 
telephone conversation with the staff the licensee concurred that 
Section III.G.1 is the appropriate reference.
    This exemption was requested by the licensee in response to 
inspection findings identified in inspection reports 50-282/87-004, 50-
282/88-013, 50-282/92-011 and 50-282/94-004. These findings addressed a 
concern with circuit failure modes that could adversely affect the 
ability to maintain hot shutdown in the event of a control room fire. 
This condition could occur if the power operated relief valves (PORV) 
block valves were not shut and a hot short damaged the PORV control 
circuit causing the PORV to open and remain open. Specifically, this 
involves the high/low pressure interface spurious signal concerns 
associated with Unit 1 PORVs CV-31231 and CV-31232 and their associated 
block valves MOV-32195 and MOV-32196 and with Unit 2 PORVs CV-31233 and 
CV-31234 and their associated block valves MOV-32197 and MOV-32198. As 
a precaution to prevent the potential loss of reactor coolant system 
(RCS) inventory during a control room fire, the licensee has proposed 
to close the PORV block valves prior to control room evacuation. The 
licensee also proposed to remove the PORV control circuit fuses to 
prevent a hot short or short to ground which may cause the PORV to open 
or be maintained open. As stated above, removal of fuses for isolation 
in such circumstances is considered a repair and, therefore, does not 
meet Appendix R, Section III.G.1, as interpreted by the staff.
    The licensee's proposed actions of closing the PORV block valves 
and removing the control circuit fuses was reviewed by the staff and 
was found to be an effective means of assuring that a control room fire 
will not result in a sustained loss of RCS inventory.
    The substance of the licensee's submittal was reviewed by Region 
III inspectors during the inspection conducted from July 18-22, 1988. 
The inspection findings were documented in NRC Inspection Report No. 
50-282/88-013 and 50-306/88-013. The inspectors walked down the control 
room evacuation shutdown procedures. Step 3.3.1 of Procedure F5, 
Appendix B, ``Control Room Evacuation (Fire),'' directs the operators 
to remove/pull the fuses for the PORVs as an immediate action in 
response to a control room evacuation. The inspectors found that the 
fuse panels were readily accessible and the fuses were clearly 
identified in the panels. The inspectors also found that sufficient 
space is available to permit access for pulling fuses and that 
emergency lights and the fuse pullers had been provided in the vicinity 
of each panel. A training program has been established for all plant 
operators to enhance the familiarity with and proper response to the 
control room evacuation. Additionally, as a part of Emergency Operating 
Procedures (EOP) training, all the operators are trained on 
[[Page 12991]] the above-mentioned procedures to ensure their 
familiarity with respect to the removal of fuses during hot shutdown. 
Therefore, operators are trained and experienced in removing the fuses.
    On the basis of this evaluation, the Commission concludes that the 
proposed action to close the PORV block valves prior to control room 
evacuation and to remove fuses from the PORV control circuit provides 
reasonable assurance that safe shutdown can be achieved in the event of 
a control room fire and is acceptable.

III

    The Commission has determined, pursuant to 10 CFR Part 50.12, that 
this exemption as described in Section II above is authorized by law, 
will not present an undue risk to the public health and safety, and is 
consistent with the common defense and security. Furthermore, the 
Commission has determined that special circumstances as provided in 10 
CFR 50.12(a)(2)(ii), are present in that application of the regulation, 
as interpreted by the staff, in the particular circumstances is not 
necessary to achieve the underlying purpose of the rule. The underlying 
purpose of Section III.G.1 of Appendix R is to ensure that safe 
shutdown can be achieved notwithstanding a fire or the consequences 
therefrom. Application of this section to the extent it precludes the 
removal of fuses as a fire protection feature is not necessary to 
achieve the underlying purpose of the rule because the licensee's 
proposal still provides reasonable assurance that one safe shutdown 
train will be operable and free of fire damage.

IV

    Accordingly, the Commission hereby grants an exemption from the 
requirements of Section III.G.1 of Appendix R to 10 CFR Part 50 to 
allow removal of fuses from the PORV control circuit in the event of a 
control room fire.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (59 FR 62415).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 21st day of February 1995.
    For the Nuclear Regulatory Commission.

John N. Hannon,
Acting Director, Division of Reactor Projects--III/IV, Office of 
Nuclear Reactor Regulation.
[FR Doc. 95-5773 Filed 3-8-95; 8:45 am]
BILLING CODE 7590-01-M