W3P89-0510, Responds to Station Blackout Rule for Plants Using Ac Independent Station Blackout Response Power,Per 10CFR50.63 Amended on 880721

Responds to Station Blackout Rule for Plants Using Ac Independent Station Blackout Response Power,Per 10CFR50.63 Amended on 880721

ML20245A400
Person / Time
Site:	Waterford
Issue date:	04/14/1989
From:	Burski R LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
W3P89-0510, W3P89-510, NUDOCS 8904250183
Download: ML20245A400 (5)

Text

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P. O. BOX 60340 LOUISI POWER AN A

& LlGHT / 317 BARONNESTREET NEW ORLEANS, LOUIStANA 70160 *

(504) 595-3100

(?$0$50$

April 14, 1989 W3P89-0510 A4.05 QA U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

SUBJECT:

Waterford Steam Electric Station Unit Number 3 Docket Number 50-382 Response to Station Blackout Rule For Plants Using AC Independent Station Blackout Response Power

REFERENCE:

NRC Letter from Ashok C. Thadani to William H. Rasin, NUMARC, dated October 7, 1988 Gentlemen:

On July 21, 1988, the Nuclear Regulatory Commission (NRC) amended its regulations in 10 C.F.R., 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:

A. A proposed station blackout duration including a justification for the selection based on the redundancy and reliability of the onsite emergency AC power sources, the expected frequency of loss of offsite power, and the probable time needed to restore offsite power; B. A description of the procedures that will be implemented for station blackout events for the duration (as determined in A above) and for recovery therefrom; and C. A list and proposed schedule for any needed modifications to equipment and associated procedures necessary for the specified SB0 duration.

8904250183 890414 PDR ADOCK 05000382 W<O P PDC t "AN EQUAL OPPORTUNITY EMPLOYER" l

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Page 2 W3P89-0510 April 14, 1989 'j The NRC has issued Regulatory Guide 1.155 " Station Blackout" which describes a means acceptable to the NRC Staff for meeting the requirements of 10 C.F.R. 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.

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.

Louisiana Power & Light has evaluated'the Waterford SES Unit No. 3 against the requirements of the SB0 rule using the 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 plant 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 P2 based on:

a. Expected frequency of grid-related LOOPS - does not exceed once per 20 years (Section 3.2.1, Part IA, p. 3-3);

b. Estimated frequency LOOPS due to extremely severe weather places the plant in ESW Group 3 (Section 3.2.1, Part 1B, P.3-4);

c. Estimated frequency of LOOPS due to severe weather places the plant in SW Croup 1 (Section 3.2.1, Part IC, p. 3-7);

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d. The offsite power system is in the I3 group (Section 3.2 1, 1

! Part ID, p. 3-10);

'2. The emergency AC power configuration group is "C" based on:

(Section 3.2.2, Part 2C, p. 3-13);

a. There are two (2) emergency AC power supplies not credited as alternate AC power sources (Section 3.2.2, Part 2A, p.

3-15);

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Page 3 W3P89-0510 April 14, 1989

b. One (1) emergency AC power supply is necessary to operate  ;

safe shutdown equipment following a loss of offsite power l (Section 3.2.2, Part 2B, p. 3-15).

3. The target EDG re., ability is 0.975.

a. A target EDG reliability of 0.975 was selected based on having a nuclear unit average EDG reliability-for the last 50 demands greater than 0.94-consistent with NUMARC 87-00, Section 3.2.4.

B. SB0 Procedure Description

' Plant procedures have been reviewed and modified to 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; LP&L Emergency Procedures for Restoration of Offsite Power to Waterford 3

2. Severe weather per NUMARC 87-00, Section 4.2.3; OP-901-045 -

Severe Weather and Flooding Plant procedures have been reviewed and changes necessary to meet NUMARC 87-00 will be implemented in accordance with 10CFR50.63 in the following area:

1. Station blackout response per NUMARC 87-00, Section 4.2.1; OP-902-005 - Degraded Electrical Distribution Recovery Procedure C. Proposed Modifications and Schedule The ability of Waterforo SES Unit No. 3 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 G7-00, Section 7, with the following res> tits:

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 approximately 80,000 gallone of water are required for decay heat removal for four hours (NUMARC 87-00, Section 3.2.5). The minimum permissible condensate storage tank level per technical specifications provides 170,000 gallons of water, which exceeds the required quantity for coping with a four-hour station blackout.

Page 4 W3P89-0510 April 14, 1989

2. Class IE Battery (ies) Capacity (Section 7.2.2)

A battery capacity calculation verifies that the Class IE batteries have sufficient capacity to meet station blackout i for four hours assuming loads not needed to cope with a station blackout are stripped. These loads are identified in plant procedures.

3. Compressed Air (Section 7.2.3)

Air-operated valves relied upon to cope with a station blackout for four hours can either be operated manually or have sufficient backup sources independent of the preferred and blacked out unit's Class 1E power supply. Valves requiring manual operation or that need backup sources for operation are identified in plant procedures.

4. Effects of Loss of Ventilation (Section 7.2.4)

a. FOR PWR L

The calculated steady state ambient air temperature for the

! steam driven EFW pump room (the dominant area of concern for a PWR) during a station blackout induced loss of ventilation is 90*F.

b. Control Room Complex for PRR The assumption in NUMARC 87-00, Section 2.7.1, that the control room will not exceed 120*F during a station blackout has been assessed.

The contral room at Waterfo'rd SES unit No. 3 does not exceed 120*F during station blackout. Therefore, the control room is not a dominant area of concern; Reasonable assurance of the operability of station blackout equipment in the above dominant areas (s) of concern has been assessed using Appendix F to NUMARC 87-00 or the Topical Report. No modifications or associated procedures are required to provide reasonable assurance for equipment operability.

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5. Containment Isolation (Section 7.2.5) 1 The plant list of containment isolation valves has been reviewed l to verify that valves which must be capable of being closed or j that must be operated (cycled) under station blackout conditions.

can be positioned (with indication) independent of the preferred and blacked-out unit's Class IE power supplies. No plant )

modifications or associated procedure changes were determined j to be required to ensure that appropriate containment integrity 1 can be provided under SB0 conditions.

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. A plant-specific analysis was used for this assessment.

The expected rates of reactor coolant inventory loss under SB0 conditions do not result in core uncovery in a SB0 of four hours.

Therefore, makeup systems in addition to those currently available under SB0 conditions are not required to maintain core cooling. ,

The information provided in thie letter is in accordance with a standard level of detail recommendation provided by the Nuclear Utility Group on Station Blackout (NUGSBO) and the Nuclear Utility Management Resource Council (NUMARC) and which LP6L understands has been reviewed and concurred with by the NRC as documented in the referenced letter.

P3 ease contact me or Robert J. Murillo should there be any questions concerning this letter.

Yours very truly, R.F. raki Manager Nuclear Safety & Regulatory Affairs RFB/RJM/ssf l

cc: E.L. Blake, W.M. Stevenson, J.A. Calvo, D.L. Wigginton, R.D. Martin,

.A. Singh, NRC Resident Inspector's Office (W3)

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