ML20245B327: Difference between revisions

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#REDIRECT [[PY-CEI-NRR-0995, Responds to Station Blackout Rule Using HPCS Div III as Alternative Ac Power.Section 50.63 Requires That Licensee Submit Proposed Station Blackout Duration Including Justification for Selection Based on Redundancy]]
| number = ML20245B327
| issue date = 04/17/1989
| title = Responds to Station Blackout Rule Using HPCS Div III as Alternative Ac Power.Section 50.63 Requires That Licensee Submit Proposed Station Blackout Duration Including Justification for Selection Based on Redundancy
| author name = Kaplan A
| author affiliation = CLEVELAND ELECTRIC ILLUMINATING CO.
| addressee name =
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000440
| license number =
| contact person =
| document report number = PY-CEI-NRR-0995, PY-CEI-NRR-995, TAC-68584, NUDOCS 8904260020
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 6
| project = TAC:68584
| stage = Other
}}
 
=Text=
{{#Wiki_filter:. _ .
THE CLEVELAND ELECTRIC ILLUMINATING COMPANY P.O. BOX 97                    3  PERRY, OHIO 44061        5      TEL 2 PHONE                      (216) 259 3737      5    ADDRESS 10 CENTER ROAD FkOM CLEVELAND: 241 1650 Serving The Best location in the Nation Al Kaplan -                                                                                                                                        A                                    ER N PY-CEI/NRR-09[5 vce entstorm                                                                          April 17, 1989 NUCLIAR GROUP U.S. Nuclear Regulatory Commission
                            . Document Control Desk Washington, D.C.                        20555 Perry Nuclear Power Plant Docket No. 50-440 TAC # 68584 Response to Station Blackout Rule Using HPCS Division III as Alternate AC Power Gentlemen:
On July 21, 1988, the Nuclear Regulatory Commission (NRC) amended its regulations in 10 CFR, 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 ava'lable 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 sources, 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.
0 8904260020 890417                                  %
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PDR ADOCK 05000440 P                                      PDC t      .
 
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:                              -                                                              .Paga 5 of 5
: 4.  . Class lE Battery (ies) Capacity (Section 7.2.2).
The station Alternate AC powers all Division III (HPCS) battery chargers.
A battery capacity calculation has been performed pursuant to NUMARC 87-00 Section 7.2.2 to verify that the non-Division III Class lE batteries have sufficient capacity to meet station blackout
                                                                -loads for four hours.
: 5. Compressed Air (Section 7.2.3)
No air-operated. valves other than safety-relief valves'(SRV's) are relied upon to cope with a station blackout for four hours using the high pressure core spray systems. The SRV's will operate either on spring pressure for over-pressure protection, or by manual operation using the air stored in the safety-related air system. The HPCS pump also delivers sufficient flow to provide make-up water for decay heat removal at depressurized conditions.
: 6. Containment Isolation (Section 7.2.5)
                                                                'The plant list of containment isolation valves has been reviewed to verify that the 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 lE power supplies. Plant modifications and associated procedure changes required to ensure that appropriate containment integrity can be provided under SB0 conditions are minor in' scope and consist of temporary Division III power supplies.for several isolation valves and appropriate lighting for this power supply connection.
The modifications and associated procedure changes identified in Parts A, B-and C above vill be completed within one year after notification provided by the Director, Office of Nuclear Reactor Regulation in accordance with 10 CFR 50.63(c)(3) regarding the adequacy of proposed station blackout l                                                    measures. This implementat!on schedule for equipment and procedure changes l-                                                  meets and exceeds related requirements in 10 CFR 50.63(c)(4). If you have further questions, please feel fre to call.
Very truly yours, h7t
[
Vice President
: l.                                                                                            Nuclear Group AK:nje cc:    T. Colburn NRC Resident Inspectors Office USNRC Region III NUMARC
(
L- ...
 
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    ,      .            Docur:nt Control Desk                                      PY-CEI/NRR-0995L      i
      ,.                                                                              Page 4 of 5 C. Proposed Modifications and Schedules l                            The AAC power source has the capacity and capability to power the l                            equipment necessary to cope with a SB0 in accordance with NUMARC 87-00, Section 7 for the required coping duration determined in accordance with l                            NUMARC 87-00, Section 3.2.5 with minor plant modifications discussed in Paragraph 6 below.
: 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 less than 150,000 gallons of water are required for decay heat removal for four hours. The minimum permissible condensate storage tank level per Technical Specifications provides 150,000 gallons of water.
The suppression pool provides an additional 800,000 gallons of recyclable water as an alternate HPCS pump supply, using Division III power. Appropriate instructions vill be added to procedures described in B to align HPCS pump suction to the suppression pool if needed. In addition, containment upper pool makeup will be available with an additional 200,000 gallons. Plant modifications necessary to utilize upper pool vater are minor in scope and consist of temporary Division III power supplies for two isolation valves and appropriate lighting for this power supply connection.
Total water sources exceed the quantity required for coping with a four-hour station blackout.
: 2. Effects of Loss of Ventilation (Section 7.2.4)
: a. The assumption in NUMARC 87-00, Section 2.7.1 that the control room vill not exceed 120*F during a station blackout has been assessed. The control room does not exceed 120'F during a station blackout. Therefore, the control room is not a dominant area of concern.
: b. HVAC for the HPCS Svitchgear Room (a dominant area of concern) is not available or necessary. Temperatures are calculated to    j remain below 130'F for the four hour blackout period.            ;
Reasonable assurance of the operability of station blackout    l i
response equipment in this area has been assessed using Appendix F to NUMARC 87-00.
No design modifications are required. Procedures vill require that the door to this room be opened to provide additional assurance of equipment operability.                            ,
: 3. Reactor Coolant Inventory (Section 2.5)
Tht: AAC source powers the necessary make-up systems to maintain adequate reactor coolant system inventory to ensure that the core is cooled for the required coping duration.
 
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Page 2 of 5 1
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The NRC has issued Regulatory Guide 1.155 " Station Blackout" which describes a    j means acceptable to the NRC Staff for meeting the requirements of                    ;
10 CFR 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 Vater Reactors" slso 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.
The Cleveland Electric Illuminating Company (CEI) has evaluated the Perry Nuclear Power Plant (PNPP) 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 parentheses.
A.        Proposed Station Blackout Duration NUMARC 87-00, Section 3 was used to determine a proposed SB0 duration of four hours.
The following plant factors were identified in determining the four hour station blackout duration:
: 1. AC Power Design Characteristic Group is P1 based on:
: a. Expected frequency of grid-related LOOPS does not exceed once  ,
per 20 years (Section 3.2.1, Part 1.A, p. 3-3);                '
: b. Estimated frequency of LOOPS due to extremely severe weather places the plant in ESV Group 1 (Section 3.2.1, Part 1.B,
: p. 3-4);
: c. Estimated frequency of LOOPS due to severe weather places the plant in SV Group 2 (Section 3.2.1, Part IC, p. 3-7);
: d. The off-site power system is in the I1/2 Group (Section 3.2.1, Part 1D, p. 3-10).
I                              2. The emergency AC (EAC) power configuration group is C based on:  (Section 3.2.2, Part 2.C, p. 3-16).
: a. There are two emergency AC power supplies not credited as alternate AC power sources (Section 3.2.2, Part 2.A, p. 3-15);
: b. One emergency AC power supply is necessary to operate safe shutdown equipment following a loss of off-site power (Section 3.2.2, Part 2.B, p. 3-15).
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: 3. The target EDG reliability is 0.95.
!                                    A target EDG reliability of 0.95 was selected based on having a                      l nuclear unit average EDG reliability for the last 50 demands greater than 0.94; consistent with NUMARC 87-00, Section 3.2.4.
: 4. An alternate AC (AAC) power source vill me utilized at PNPP vhich meets the criteria specified in Appendix B to NUMARC 87-00. The AAC source is an EAC power source which meets the assumptions in L                                    Section 2.3.1 of NUMARC 87-00.
The AAC power source is available within ten minutes of the onset of the station blackout event and has sufficient capacity and capability to operate systems necessary for coping with a station blackout for the required SB0 duration of four hours to bring and maintain the plant in hot shutdown.
The alternate AC power source which vill be utilized at PNPP is the-Division III emergency diesel generator which provides the power for the High Pressure Core Spray (HPCS) System. The use of the HPCS for the AAC power source provides more advantages than a redundant and diverse power source. The entire AAC division, not just the power source, is completely independent from other on-site divisions. The system was designed as a source of coolant injection and is capable of maintaining the plant in hot shutdown for the expected duration of the station blackout.
The system conforms to the AAC criteria specified in Appendix B of NUMARC 87-00.. A simplified one-line diagram of'the HPCS power source is given in the attached figure'.
B. Procedure Description Plant procedures have been reviewed and vill be supplemented as necessary, to meet the guidelines in NUMARC 87-00, Section 4 in the following areas:
: 1. Station blackout response per NUMARC 87-00, Section 4.2.1: ONI-Sil, Loss of Off-site Power, and ONI-R10-1, Station Blackout (HPCS).
: 2. AC power restoration per NUMARC 87-00, Section 4.2.2:                  ONI-Sil, Loss of Off-site Power.
: 3. Severe weather per NUMARC 87-00, Section 4.2.3:            ONI-ZZZ-1, Tornado or High Vinds.
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