ML20235Y346
| ML20235Y346 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 03/03/1989 |
| From: | Mcduffie M CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.155, RTR-REGGD-1.155 NLS-89-053, NLS-89-53, TAC-68520, TAC-68521, NUDOCS 8903140083 | |
| Download: ML20235Y346 (5) | |
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Carolina Power & Light Company P. o. Box 1551 e Raleigh. N. C. 27602 SERIAL:
- gg10gg5086P2 36 MAR 0 31989 crr M. A. McDUFFIE DON '.>
- enior Vice President Ll' Nuclear Generation United States Nuclear Regulatory Commission ATTENTION:
Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 RESPONSE TO STATION BLACKOUT RULE (TAC 68520, 68521)
Gentlemen:
On July 21, 1988, the Nuclear Regulatory Commission (NRC) amended its regulations in 10CFR, Part 50.
A new section, 50.63, was added which requires that each light-water-cooled nuclear power plant be able to withstand and recover from a station blackout (SBO) of a specified duration.
Utilities are expected to have the baseline assumptions, analyses, and related information used in their coping evaluation available for NRC review. It also identifies the factors that must be considered in specifying the station blackout duration. Section 50.63 requires that, for the station blackout duration, the plant be capable of maintaining core cooling and appropriate containment integrity. Section 50.63 further requires that each licensee submit the following information:
1.
A proposed station blackout duration including a justification for the selection based on the redundancy and reliability of the on-site emergency AC power sourcea, the expected frequency of loss of off-site power, and the probable time needed to restore off-site power; 2.
A description of the procedures that will be implemented for station blackout events for the duration (as determined in 1 above) and for recovery therefrom; and 3
A list and proposed schedule for any needed modifications to equipment and associated procedures necessary for the specified SB0 duration.
The NRC has issued Regulatory Guide 1.155 " Station Blackout" which describes a means acceptable to the NRC Staff for meeting the requirements of 10CFR 50.63 Regulatory Guide (RG) 1.155 states that the NRC Staff has determined that NUMARC 87-00 " Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors" also provides guidance that is in large part identical to the RG 1.155 guidance and is acceptable to the NRC Staff for meeting these requirements.
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Table 1 to RG 1.155 provides a cross-reference between RG 1.155 and NUMARC 87-00 and notes where the RG takes precedence.
' Carolina Power & Light Company has evaluated the Brunswick Steam Electric Plant, Units 1 and 2 against the requirements of the SB0 rule using guidance from NUMARC 87-00 except-where RG 1.155 takes precedence. The results of this evaluation _are detailed below.
(Applicable NUMARC 87-00 sections are shown in parenthesis.)
A.
Proposed Station Blackout Duration NUMARC 87-00, Section 3 was used to determine a_ proposed SB0 duration of four hours.
No modifications were required to attain this proposed coping duration category.
The'following plant factors were identified in determining the proposed station blackout duration:
1.
AC Power Design Characteristic Group is P3* based on:
a.
Expected frequency of grid-related LOOPS - does not exceed once per 20 years-(Section 3.2.1, Part 1A, page 3-3);
b..
Estimated frequency of LOOPS due to extremely severe weather places the plant in ESW Group 5 (Section 3 2.1, Part 1B, page 3-4);
c.
Estimated frequency of LOOPS due to severe weather places the plant in SW Group 2 (Section 3.2.1, Part 1C, page 3-7);
d.
The off-site power system is in the I1/2 Group (Section'3.2.1, Part 1D, page 3-10);
e.
Plant-specific pre-hurricane shutdown requirements and procedures which meet the guidelines of Section 4.2.3 of NUMARC 87-00 have been implemented.
2.
The emergency AC power configuration group is C based on:
(Section 3.2.2, Part 2C, page 3-13) a.
There are two emergency AC power supplies not credited as alternate AC power sources per unit (Section 3 2.2, Part 2A, page 3-15):
b.
One emergency AC power suppij per unit is necessary to operate safe shutdown equipment following a loss of off-site power (Section 3.2.2, Part 2B, page 3-15).-
3.
The target EDG reliability is 0.975.
A target EDG reliability of 0 975 was selected based on having nuclear unit average EDG reliability for the last 100 demands greater than 0.95 consistent with NUMARC 87-00, Section 3.2.4.
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Procedure Description Plant procedures have.been reviewed and modified, if necessary,fto meet the guidelines in NUMARC 87-00, Section 4 in the following areas 1.-
AC power restoration per NUMARC 87-00, Section 4.2.2; Procedure DTRM-GP-2; Restoration of Service Following A System o
Shutdown - Eastern Area; o:
- 0perating Procedure OP-50; Plant Electrical System Operating' Procedure; Operating Procedure, OP-50.1; Diesel Generator Emergency Power o
System;0perating Procedure.
2.
Severe weather per NUMARC 87-00, Section 4.2 3 o
BSEP. Administrative Instruction, AI-68; Brunswick Nuclear Project-Response to Severe. Weather Warnings; Abnormal Operating Procedure, AOP-13.0; Operation during o
Hurricane, Tornado, or Flood Condit. ions.
_ Plant procedures have been reviewed and changes necessary to meet NUMARC 87-00 will be implemented in'the following areas:
1.
Station blackout response per NUMARC 87-00, Section 4.2.1; o
Emergency Operating Procedures, BSEP E0P-01; o
Abnormal Operating Procedure, A0P-36.0; Loss of Off-site Power.
2.
Procedure changes associated with any modifications required after-assessing coping capability per NUMARC 87-00, Section 7.-
C.
Proposed Modifications and Schedule The ability of Brunswick Steam Electric Plant, Units 1 and 2 to cope with a station blackout for four hours in accordance with NUMARC 87-00, Section 3.2.5 and as determined in Section "A" above, was assessed using NUMARC 87-00, Section 7 with the following results:
1.
Condensate Inventory for Decay Heat Removal (Section 7.2.1)
It has been determined from Section 7.2.1 of NUMARC 87-00 that 91,300 gallons of water are required for decay heat removal for the l
four hour coping duration category from NUMARC 87-00, Section 3.2.5.
The minimum permissible condensate storage tank level per technical specifications provides 100,000 gallons of water, which exceeds the required quantity for coping with a four hour station blackout.
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'NLS-89-053 / P ga 4 No plant modifications or procedure changes are needed to utilize this water source.
2.
Class 1E Battery Capacity (Section 7.2.2)
The Class 1E battery was determined to be inadequate to meet station blackout loads for four hours. The following modifications and/or procedure changes are necessary to provide a four-hour capacity:
either modifications will be performed to increase the plant battery capacity to cope for the fcur hour station blackout duration; or modifications and procedural revisions will be implemented to permit the blacked out unit's battery charger to be powered from the non-blacked out unit's EAC power source, utilizing existing cross connections of the 4 KV buses.
3 Compressed Air (Section 7.2 3)
Air-operated valves that are relied upon to cope with a station blackout for four hours have sufficient backup sources independent of the preferred and blacked out unit's Class 1E power supply.
4.
Effects of Loss Ventilation (Section 7.2.4) a.
For BWRs The steady state ambient air temperature has been calculated for the following dominant areas of concern:
Area Temperature HPCI / HPCS 152 F RCIC Room and Pipe Chase 145 F ECCS Pipe Tunnel 131 F b.
The assumption in NUMARC 87-00, Section 2.7.1 that the control 0
room will not exceed 120 F during a station blackout has been assessed. The control room at BSEP, Units 1 and 2 will not exceed 120 F during a station blackout. Therefore, the control room is not a dominant area of concern.
Reasonable assurance of the operability of station blackout response equipment in the above dominant area (s) of concern has been assessed using Appendix F to NUMARC 87-00 and/or the Topical Report. No modifications or associated procedures are required to provide reasonable assurance for equipment operability.
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-Containment Isolation (Section 7.2.5)
The plant list of. containment isolation valves has been reviewed to verify that valves which must be capable of being closed or that must be operated'(cycled) under station blackout conditions can be-positioned _ (with indication) independent of the preferred and blacked-out unit's Class 1E power supplies. The following modifications and/or associated procedure changes are required to ensure that appropriate containment integrity can be provided under station blackout conditions:
Abnormal Operating Procedure A0P-36.0 will be revised to sequentially supply power from the non-blacked out unit's EAC power source to MCCs XA, XB, XC, and XD in the blacked out unit to monitor position and/or close a select grouping of RHR and core spray valves.
6.
Reactor Coolant Inventory (Section 2.5)
The ability to maintain adequate reactor coolant system inventory to ensure that the core is cooled has been assessed for four hours. The generic analyses listed in Section 2 5.2 of NUMARC 87-00 were used for this assessment and are applicable to the, specific design of BSEP. The expected. rates of reactor coolant inventory loss under SB0 conditions do not result in more than a momentary core uncovery in a SB0 of.four hours. Therefore, make-up systems in, addition to those currently available~under SB0 conditions are not required to maintain core cooling under natural circulation-(including reflux boiling).
In addition to the modification-to increase battery capability, enhanced battery voltage indication and an AC independent containment pressure indication will be provided.
The modifications and associated procedure. changes identified in Parts B and C above will be completed within 2 years after the notification provided by the Director, Office of Nuclear Reactor Regulation in accordance with 10CFR 50.63 (c) (3).
If you should have any questions, please contact Mr. S. D. Floyd at (919) 546-6901.
Yours very truly, L
M. A. McDuffie DJK/che (230CRS) cc:
Mr. S. D. Ebneter Mr. W. H. Ruland Mr. E. G. Tourigny NUMARC
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