U-601427, Forwards Response to Station Blackout rule,10CFR50.63, Satisfying Requirement That Proposed Station Blackout Coping Duration,Description of Procedures to Be Implemented & List of Mods,As Required,Be Submitted
| ML20245A850 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 04/16/1989 |
| From: | Holtzscher D ILLINOIS POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| U-601427, NUDOCS 8904250413 | |
| Download: ML20245A850 (9) | |
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/LLIN0/S POWER 00MPANY CLINTON POWER STATION, P.o. BOX 678, CLINTON. ILLINOIS 61727 April 16, 1989 10CFR50.63 Docket No. 50-461 Document Control Desk Nuclear Regulatory Commission-Washington, D.C.
20555
Subject:
Clinton Power Station Resnonse to the Station Blackout Rule
Dear Sir:
Attached is Illinois Power Company's (IP) response to the Station Blackout (SBO) rule, 10CFR50.63, for the Clinton Power Station (CPS).
' This response satisfies the requirement of the rule (paragraph c(1)) to submit the following information:
(i)
A proposed station blackout coping duration (ii) A description of the procedures to be implemented (iii)-A list of modifications, if any are required The station blackout coping duration for CPS is four hours. No plant modifications are required in order to meet this coping duration.
However, some minor procedure changes ace required. These changes are
' identified in CPS's attached response f.o the Station Blackout Rule.
I The attached response is based cn the generic response format for stations using the class lE electrica'. Division III as an Alternate AC (AAC) power supply. This response fo rmat was developed by Devonrue Ltd., for those BWRs which have a High Pressure Core Spray (HPCS) system powered by a dedicated Division III diesel-generator. The CPS Division III diesel-generator meets the criteria for an AAC, and it can be shown by test to be available to power the Division III electrical bus within j
ten minutes of the onset of a station blackout. Although paragraph (c)(2) of the rule states that no coping analysis is required for stations having alternate AC available to'the buses within ten minutes, l
since the' CPS Division III diesel-generator does not supply power to all I
essential HVAC loads, battery charger loads other than Division III, or compressed air loads, IP has performed a coping q{
8904250413 890416 PDR ADOCK 05000461 P
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analysis of CPS to satisfy paragraph (a)(2) of the rule.
This analysis follows the methodology of NUMARC 87-00, " Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors." The format of the attached response is a combination of the AAC generic response format and the AC independent generic response format, both of which were developed by NUMARC and approved by the NRC.
IP and our contractor (Devonrue Ltd) discussed this modified response format with the NRC staff in a meeting on February 14, 1989 and revised it to incorporate the comments which were expressed at that meeting.
The baseline assumptions, analyses, and related information used in the coping evaluations are available at CPS for review.
Please contact me if there are any questions or comments regarding this information.
Sincerely yours, VM D. L. Holtzscher Acting Manager -
Licensing and Safety JCA/krm Attachments cc:
NRC Resident Office NRC Region III, Regional Administrator NRC Clinton Licensing Project Manager Illinois Department of Nuclear Safety NUMARC Mr. Vittorio Pareto, Ph.D., Devonrue, Ltd.
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CLINTON POWER STATION RESPONSE TO THE STATION BLACKOUT RULE (BWR/6 USING DIVISION III AS ALTERNATE AC POWER)
Background
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 recaver 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 bl.ckout coping 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 Item 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 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.
Illinois Power Company (IP) has evaluated the Clinton Power Station (CPS) 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.)
(1)
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Attachmant
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to U-601427 Evaluation Results 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 proposed station blackout duration:
1.
AC Power Design Characteristic Group is P1 based on:
a.
Expected frequency of grid-related Losses of Off-Site Power (LOOPS) - does not exceed once per.20 years (Section 3.2.1, Part lA, p. 3-3);
b.
Estimated frequency of LOOPS due to extremely severe weather places the plant in ESW Group 1 (Section 3.2.1, Part 1B, p. 3-4);
c.
Estimated frequency of LOOPS due to severe weather places the plant in SV Group 2 (Section 3.2.1, Part 10, p.'3-7);
d.
The off-site power system is in the 11/2 Group (Section 3.2.1, Part 1D, p. 3-10);
e.
Plant-specific pre-hurricane shutdown requirements and procedures which meet.the guidelines of Section 4.2.3 of NUMARC 87-00.are not applicable to CPS (Section 3.2.1, Part lE, p. 3-12).
.2.
The emergency AC power configuration group is C based on:
(Section 3.2.2, Part 2C, p. 3-13) a.
There are two emergency AC power supplies'not credited as alternate AC power sources (Section 3.2.2, Part 2A,
- 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 2B, p. 3-15).
3.
The target emergency diesel generator (EDG) reliability is 0.95.
This target EDG reliability was selected based on having a nuclear unit average EDG reliability for the last 20 demands greater than 0.90 consistent with NUMARC 87-00, Section 3.2.4 4.
An alternate AC (AAC) power source will be utilized at CPS which meets the criteria specified in Appendix B to NUMARC 87-00.
The AAC source is an emergency AC (EAC) power source which meets the assumptions in Section 2.3.1 of NUMARC 87-00.
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j-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 the plant to and maintain it in safe shutdown.
The alternate AC power source which will be utilized at CPS is the Division III emergency diesel generator which provides the power for the High Pressure Core Spray (HPCS)
System.
For the BWR/6 reactor at CPS the use of the HPCS for the AAC power source provides more advantages than a redundant and diverse power source.
The system includes its own safe shutdown equipment totally isolated from the unit's normal shutdown busses. 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 a hot chutdown 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 modified, if necessary, 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; CPS 4200.01, Loss of AC Power IP Electric System Restoration Procedure Dispatchers operating guidelines l
2.
Severe weather per NUMARC 87-00, Section 4.2.3 CPS 4302.01, Tornado /High Wind 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; CIS No. 3211.01 Shutdown Service Water CPS No. 3203.01 Component Cooling Water CPS No. 3212.01 Plant Service Water CPS No. 3214.01 Plant Air (Instrument Air and Service Air)
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Attachment to U-601427 s-2.
Procedure. changes associated with any modifications required after assessing coping capability per NUMARC 87-00, Section 7.
No modifications are required.
Therefore there are no-associated procedure changes.
C.
Proposed Modifications and Schedule No modifications are necessary to utilize the AAC power source, and no modifications are necessary as a result of the coping analysis.
Cooinz Analysis Results The AAC power source has the capacity and capability to power the equipment necessary to cope with a SB0 in accordance with NUMARC 87-00, Section 7 for the required coping duration determined in accordance with NUMARC 87-00, Section 3.2.5.
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 103,000 gallons of water are required for decay heat removal for four hours.
The minimum permissible suppression pool level per 3
Technical Specifications provides 1,095,000 gallons (146,400 ft )
of water. The following additional water source has been identified as being normally available, and can provide the total required amount of water for decay heat removal for four. hours:
RCIC Storage Tank 125,000 gallons No plant modifications or procedure changes are needed to utilize this water source.
2.
Effects of Loss of Ventilation (Section 7.2.4) a.
Control Room Complex 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 control room at CPS does not exceed 120' F during a station blackout provided that the control room doors to the control room corridor are opened within one hour of the start of the SBO.
Provisions for this action are being incorporated into plant procedures.
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Attechment to U 601427 b.
HVAC systems serving the following dominant areas of concern l
are not available for use during an SB0:
PEAK 6RE6 TEMPERATURE
- F Main Steam Tunnel 213 RCIC Pump Room 139 RCIC Instrument Panel Room 142 Reasonable assurance of the operability of station blackout response equipment in the above area (s) has been assessed using Appendix F to NUMARC 87 00.
The following procedure changes are required to provide reasonable assurance of equipment operability:
Disable automatic trips for RCIC due to High Main Steam Tunnel Temperature.
3.
Reactor Coolant Inventory (Section 2.5)
The AAC sou rce powers the necessary make-up systems to maintain l
adequate reactor coolant system inventory to ensure that the core is cooled for the required coping duration.
4.
Class 1E Batterv(ies) Canacity (Section 7.2.2)
The station Alternate AC Powers all Division III battery chargers.
A battery capacity calculation verifies that the non-Division III Class lE batteries have sufficient capacity to meet station blackout loads for four hours assuming loads not needed to cope with a station blackout are stripped.
These loads are identified
)
in plant procedures.
5.
Comoressed 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 supply. Valves requiring manual operation or that need backup sources for operation are identified in plant procedures.
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. No plant modifications were determined to be required to ensure that appropriate containment integrity can be provided under SB0 conditions. However, a minor procedure change is required.
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Attachmsnt to U-601427-t No modifications were identified as necessary for CPS to meet the
~ requirements'of the rule.
Procedu're changes identified as the result of coping analyses will be completed within one year after the notification provided by the-Director,.0ffice of Nuclear Reactor Regulation in.
accordance with 10 C.F.R. 50.63(c)(3).
i.
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