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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR R' ACTOR REGULATION E
PLANT SYSTEMS BRANCH REQUEST FOR EXEMPTION FROM 10 CFR PART 50, APPENDIX R ITEM III.G.1 REQUIREMENT REGARDING HOT SHUTDOWN REPAIRS FOR A FIRE EVENT IN THE PLANT PILGRIM NUCLEAR POWER STATION, UNIT 1 DOCKET NO. 50-293
1.0 INTRODUCTION
By submittal dated October 2, 1987, Boston Edison Company, the licensee for Pilgrim, Unit 1, requested exemptions from 10 CFR Part 50, Appendix R.
Item !!I.G.I.a requirement, for perfoming repairs for maintaining plant hot shutdown following a fire in any one of certain plant areas and provided justification for the same. Specifically, the licensee proposed replacing fuses in the control circuits for RHR valves in the torus cooling mode of RHR operation which may get blown due to a fire in Fire Area (FA) 3.1 (Control Room), 3.2 (Cable Spreading Room) or 1.9 (Reactor Building, Elevation 23',
Eastside). Additionally, the licensee proposed installing a jumper wire in the control circuit for a required cooling fan that my get disabled due to a fire in FA 1.9.
The staff's evaluation of the above is given below.
2.0 EVALUATION In their submittal, the licensee stated that for a fire in FA 3.1 or 3.2, the RCIC and RHR in the torus cooling mode will be used to achieve and snaintain safe shutdown. The licensee also stated that for a fire in FA 1-9, the RHR in the torus cooling inode can be used with other applicable systems to achieve The licensee, however, identified 1n'electFTeaT-~g and maintain safe shutdown.
isolation deficiency associated with the torus cooling inode of RHR operation which could compromise the capability to maintain hot shutdown following i
certain fire events. Specifically, the licensee stated that their analysis of postulated fires in plant areas indicated that a fire in any one of 3 fire areas (FA 3.1, 3.2 or 1.9) can cause damage to the remote control circuits for the 5 valves required for torus cooling. This damage could result in blowing the associated control power fuses that are corron to both the remote and local control circuits for these valves and consequently compromise the local control capability for these valves.
The licensee pointed out that transfering the control of the needed valves from the control room to a local control station (i.e., alternate shutdown panel) will not be sufficient to ensure local control of these valves.
Control would be lost if their connon fuses are blown prior to such transfer.
l To ensure local control of the 5 valves, the licensee proposed to replace the blown control power fuses for the affected valves in a timely Nnner af ter effecting the transfer of the 5 valves to local control.
Specifically, for a fire in any one of the above 3 areas, the licensee proposed to transfer i
control of the needed valves from the control room to an alternate shutdown panel (ASP) located in a fire area different from the affected fire area using 4
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2 the respective transfer switches for the valves on the panel and replace the blow, fuses at the MCC located adjacent to the ASP. The licensee stated that one of two sets (i.e., each set containing one ASP and one adjacent MCC) nsociated with the valves of the corresponding train of two RHR trains will oe utilized depending upon the fire location. One of these sets is located in FA 1.9 and the other is located in FA 1.10 (Reactor Building Elevation 23',
i West side). For a fire in FA 3.1 or 3.2, the licensee will use either of j
these sets; for a fire in FA 1.9, the licensee will use the set located in FA 1.10.
The licensee further stated that at any one time, no more than 5 fuses will need to be replaced and the need for replacement will be identified by the absence of indicating lights above the respective control switches for the valves.
The licensee stated that sufficient time will be available for replacing the blown fuses since they have confimed that a single operator can replace 5 fuses within 20 minutes. General Electric Company (GE) has determined that at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> are available to perform these replacements before torus cooling will be required. The licensee also stated that the fuses are correctly sized I
and clearly marked for use and that all necessary tools and additional spare fuses will be maintained nearby. Also, adequate lighting has been provided for the MCC cubicles containing the fuses to facilitate fuse replacement.
In this context, the staff notes that the fuse replacement will not result in undue operator hazard since it involves only control power fuses.
In their submittal, the licensee stated that a fire in FA 1.9 can additionally l
i disable control of a fan which, in turn, will disrupt the cooling of the area in the Reactor Building housing various needed hot shutdown components. The licensee has calculated that 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after loss of area cooling, the area temperature can rise to 209'F, the value established for environmental qualification for the equipment in the area.
T'.a licensee has therefore i
proposed to install a jumper wire (hot shutdown repair) in the fan control circuit at the applicable MCC (located in FA 1.10) which is outside the affected fire area.
The licensee stated that sufficient time will be available for the jumper wire installation since they have detemined that j
the task can be completed in less than one hour. The licensee further stated that the properly sized jumper will be kept in one of the alternate shutdown tool boxes (located in switch gear rooms).
The licensee has committed to implement the above procedures prior to plant startup from the current refueling outage (RFO) No. 7.
The licensee further stated that the procedures for plant shutdown outside the control room (at the ASP) include all actions to be taken for fuse replacement, when they I
have to be taken, and identify the MCC and the breaker number for each i
component whose fuse may require replacement. Also, supplemental procedures on post-fire shutdown in specific areas including the Reactor Building are j
being developed (to be completed and implemented prior to plant startup from RF0 No. 7). These will give instructions to the operators as to when and how to install the jumper wire. The licensee connitted to train the operators in the above procedures prior to startup.
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.' Based on the above, the staff has determined that the licensee's proposed manual actions including the hot shutdown repair, i.e., fuse replacement, meet the intent and purpose of IE Information Notice No. 85-09, "Isolation Transfer Switches and Post-Fire Shutdown Capability", dated January 31, 1985. The staff has further determined that the other proposed hot shutdown repair, 4
i.e., jumper installation (to facilitate performance of a support function, i.e.,
cooling the applicable a ea, to maintain hot shutdown), can be completed in a tirely manner so as not o compromise maintaining hot shutdown.
3.0 CONCLUSION
Based on the above, the staff finds the licensee's proposed manual actions i
4 including the above hot shutdown repairs for Pilgrim. Unit 2, to be acceptable.
The staff further recommends that the licensee's request for exemptions from Appendix R. Item III.G.1 requirement, for performing the above hot shutdown repairs be granted.
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i PSR SALP INPUT Plant Name:
Pilgtim Nuclear Power Station, linit 1 Licensee:
Boston Edison Company Docket No.:
50-293 SER
Subject:
Recuest for Exemption from 10 CFR Part 50, Appendix P Item III.G.1 Pequirement Pegarding Hot Shutdown Repairs for a Fire Event in the Plant PERF0PPANCE (1) Manaaement Involvement in Assurino Ocality PARAMETERS:
(0) Approach to Resolution of Techdical issues from a Safety Standpoint (3
Pesponse to NRC Initiatives (4
Staffing (Including Management)
(5 Pcporting and Analysis of Peportable Events i
(6 Trainina and Oualification Effectiveness 1
(7 Any other SALP Functional Area PERFORMANCE NAPPAT'iVE DESCRIPTION OF CATEGORY / RATING J
PARM ETER LICENSEE'S PERFORFANCE (1)
Licensee's manaaeevnt invulvement as 1
evidenced by the completeness of the submittC,
(2)
Licensee's submittal was thorough and 1
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addressed all concerns satisfactorily (3)
No NPC initiatives were reouired.
1 (4)
Not applicable 1
(Si Not applicable (6)
Not applicable I
(7)
Not applicable l
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Overt'1 Pating:
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