ML20056B534
| ML20056B534 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 08/23/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20055H681 | List: |
| References | |
| NUDOCS 9008290230 | |
| Download: ML20056B534 (7) | |
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- UNITED STATES
. !^ c- NUCLEAR REGULATORY COMMISSION I wAsmwovow. o. c. mses SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FLORIDA POWER CORPORATION. ET AL.
CRYSTAL RIVER UNIT NO. 3 NUCLEAR GENERATING PLANT DOCKET NO. 50-302 STATION BLACK 0UT SAFETY EVALUATION
1.0 INTRODUCTION
On July 21, 1988, the Code of Federal Regulations,10 CFR Part 50, was amended to include a new Section 50.63, entitled " Loss of All Alternating Current Power," !
(Station Blackout). The Station Blackout (SBO) Rule requires that each light- '
water-cooled nuclear power plant be able to withstand and recover from an $B0 of specified duration, requires licensees to submit information as defined in Part 50.63 and requires licensees to provide a plan and schedule for conformance to the SB0 Rule. The S50 Rule further requires that the baseline assumptions, analyses and related information be available for NRC review. Guidance for con-formance to the rule is provided by Regulatory Guide (RG) 1.155, Station Blackout, ;
and NUMARC 87-00, Guidelines and Technical Bases for NUMARC Initiatives Addressing ;
Station Blackout At Light Water Reactors.
Staff review of SB0 submittals can be limited to a review of the licensee's sub-mittal and does not necessarily include a concurrent site audit review of the sup-porting documentation. However, a limited number of concurrent site. audit redews were performed to obtain a benchmark for licensee conformance with the documenta-tion requirements of the SB0 Rule. Crystal River Unit 3 was one of the plants selected by the NRC for a site audit review.
The licensee's responses to the SB0 Rule were provided by letters from R.C. Widell l to the NRC Document Control Desk dated April 17, 1989 and from P.M. Beard, Jr.
to the NRC Documtnt Control Desk dated March 30, 1990. The licensee's responses were reviewed by Science Applications International Corporation (SAIC) under i contract to the NRC. The site audit was performeo by a joint NRC/SAIC team headed by an NRC staff member on August 1-4, 1989. The results of the review and site audit are documented by a SAIC Technical Evaluation Report (TER) No. 89/1150,
" Crystal River Unit 3 Station Blackout Evaluation," dated July 11, 1990 (Attachment 1).
2.0 EVALUATION After reviewing the SAIC TER and in consideration of the information obtained by the NRC staff during the site audit review, the staff concurs with the analysis 9008290230 900823 ADOCK 0500 3 2
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and conclusions as identified in the SAIC TER. Based on this review, the staff i findings and recommendations are summarized as follows.
2.1 Station Blackout Duration The licensee has calculated a minimum acceptable SB0 duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> based on a characteristic group of "P2*", an Emergency AC (EAC) configuration group "C", and an Emergency Diesel Generator (EDG) reliability of 0.95. After reviewing the suppcrting documentation, RG 1.155, NUMARC 87-00, and SAIC's TER, the staff concurs witn SAIC that if the licensee establishes a specific procedure that directs operators to ensure that the plant is in safe shutdown 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> before l the arrival of the hurricane at the site, then the requirements of a "P2*"
characteristic group would be met. However, currently the licensee's ,
does not meet the 2-hour requirement of a "P2*" characteristic group. procedure Without such a procedure and a comitment to implement it, the Crystal River Station Unit 3 would become a "P2" characteristic group. Therefore, in order to maintain an SB0 coping duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (without the commitment and the procedure), the EDG target reliability would have to be revised from 0.95 to 0.975 in accordance with RG 1.155 and NUMARC 87-00, Based on the above and the SAIC TER, the staff does not agree with the licensee's current assessment for an S80 coping duration based on EDG target reliability of 0,95.
Recommendation: The licensee should implement pre-hurricane shutdown procedures in accordance with NUMARC 87-00, Section 4.2.3 to meet the requirements of offsite group P2* or commit to an EDG reliability target of 0.975 for calculating a 4-hour SB0 coping duration. In absence of the above, Crystal River 3 would be clas-sified as offsite group P2, EDG target reliability of 0.95 and a required SB0.
duration of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. '
2.2 Station Blackout Coping Capability ,-
The licensee has proposed coping independent of an alternate AC power source for the SB0 coping duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and recovery therefrom. Since the licensee has expressed a determination to keep Crystal River 3 as a 4-hour SB0 coping duration plant, the staff review is based on the 4-hour coping duration. In case Crystal River 3 chooses the 8-hour SB0 coping duration, our evaluation of the licensee's submittal would have to be revised.
2.2.1 Condensate Inventory for Decay Heat Removal An analysis performed by the licensee showed that sufficient water is available in the Emergency Feedwater Storage Tank (EFWST) for decay heat removal during a 4-hour SB0 duration.
After rev1 ewing the available information and SAIC's TER, the staff agrees with the licensee's assessment that the plant has adequate condensate inventory for a 4-hour duration. In addition, the excess inventory available in the EFWST could be csed to assist in the SB0 recovery.
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- 2 2.2.2 Class IE Battery Capacity The licensee has performed battery capacity calculations which indicate that Class IE batteries do not have sufficient capacity for the 4-hour SB0 coping duration. Therefore, the licensee has proposed stripping loads that are not required for SB0 coping, including normal battery-backed loads in the control room (lighting, instrumentation, controls, etc.) in order to extend the battery capacity to meet the 4-hour coping duration. To shed loads in the control room, the licensee has proposed to disable and evacuate the main control room and transfercontrolsforplantshutdowntotheremoteshutdownpanel(AppendixR).
The staff finds the disablement and evacuation of the control room to be unac-ceptable. The normal battery-backed plant monitoring and electrical control systems that are an integral part of the control room are considered by the staff
-to be essential for successfully coping with and recovering from an SBO. Since the remote shutdown panel does provide some of the functions which are required for minimum SB0 coping capability, it is considered by the staff to provide ac-ceptable means to assist in the control of the plant during an SB0. However, the staff does not consider that the shutdown panel provides control of the plant as normally would be provided by a fully manned and functional control room during an SBO.
The NRC position regarding the disablement and evacuation of the control room was comunicated to the licensee. In a meeting with the NRC and in a March 30, 1990 submittal, the licensee stated that the control room would not be disabled and evacuated and that the licensee would provide appropriate battery capacity to power the 5B0 loads and maintain the control room functional.
The current Class IE batteries were approaching their end of life and were replaced during the 1990 refueling outage with slightly higher capacity bat-teries. However, the higher capacity Class 1E batteries alone will still not have sufficient capacity to cope with a 4-hour SB0 without stripping loads.
Therefore, the licensee proposes to also install in 1992 a non-Class IE battery to power some of the non-Class IE loads. Subject to implementation of the commit-ments described above, we find this to be acceptable.
Recommendation: The licensee's battery sizing calculations should be available for possible NRC audit. The licensee should confirm that, with the battery changes and additions, the normal battery-backed plant monitoring and electrical system controls in the control room will remain operational for successfully coping with and recovering from an SB0 event. The licensee should identify and describe the proposed modifications to the control room as result of addition "
of the non-class IE battery.
2.2.3 Compressed Air The licensee has stated that procedural changes and modifications are necessary to ensure that air-operated valves needed during the 4-hour SB0 will be operable.
In addition, the licensee has stated that the necessary modifications will be empleted within 2 years from the issuance of this Safety Evaluation (SE).
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i After reviewing the available information and the SAIC TER, the staff finds the proposed licensee actions to be acceptable provided that the modifications are sufficient to ensure that the appropriate valves will be operable for the 4-hour 580 duration. i I
Recommendation: The licensee should identify the nature and objectives of the proposeo mooirications to meet the SB0 Rule and establish a proposed schedule for implementation. )
1 2.2.4 Loss of Ventilation \
The licensee has analyzed the effects of post-SB0 steedy-state air temperatures \
for the plant areas containing SB0 equipment. The licensee has stated that the steady-state room air temperatures can be meintained within Ifmits to provide a reasonable assurance of S80 equipment operability (Refer to Attachment 1 for details).
After reviewing the supporting documentation and SAIC's TER, the staff agrees with the licensee's stated results except in the following areas: 1) EFIC room C, 2) atmospheric dump valve enclosure area, 3) inverter room 4) the control room, ana 5) reactor building. The staff concurs with SAIC's assessment of tha deficiencies as identified in Attar.hment 1 for the above-mentioned areas.
In addition, refer to the staff's position and reconnendation under Section 2.2.2 above concerning functionally maintaining and manning of the control room to provide assurance of plant safety while coping with and recovering from an SBO.
Reconnancation: The licensee should reevaluate the effects of loss of vent 11a-tion for the areas identified in this section, correct the deficiencies as appro-priate in the supporting documentation, and implement the necessary modifications to ensure the operability of the SB0 equipment.
2.2.5 containment Isolation The licensee has reviewed the plant list of containment isolation valves (CIVs) and has stated that no plant modifications or procedure changes are required to ensure appropriate containment integrity under SB0 conditions. The licensee's revised submittal dated March 30, 1990 identified four additional containment l
isolation valves which had not been identified at the time of the site audit.
- Although these valves do not meet any of the five exclusion criteria given in NUMARC 87-00, Section 7.2.5, they have redundant valves on the other side of their penetrations which do meet at least one of the criteria. Therefore, appropriate containment isolation can be met without operator action.
After reviewing the SAIC TER, the staff concurs that the licensee's review is consistent with the guidance of RG 1.155 and NUMARC 87-00.
Reconnendation: Identification and location of the four containment isolation valves not previously identified at the time of the site audit should be available for possible future NRC audit.
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2.2.6 Reactor Coolant Inventory The licensee has stated that a new inventory analysis will be submitted to the i staff af ter the completion of a generic analysis currently being performed by j the reactor manufacturer (approximately the first quarter of 1990). There-fore, pending the staff's review, this issue will be held open. If the new analysis is not found acceptable by the staff or if the new analysis does not show that adequate RCS inventory will be maintained, then the staff will expect the licensee to implement the appropriate hardware and procedure changes '
necessary to ensure that adequate RCS inventory is maintained for the SB0 event.
Recommendation: The licensee should submit the inventory analysis and any !
required modifications resulting from the analysis for staff review, l 2.3 Proposed Training. Procedure Changes and Plant Modifications The licensee has stated that the appropriate training and procedures have already been modified or will be modified to reflect the necessary requirements for an SBO. In addition, the licensee has given verbal commitments for the completion of the hardware modifications (see TER).
The above-mentioned items were not reviewed in detail as part of the SB0 plant audit. However, the staff expects the licensee to implement and maintain the procedures, proposed training and modifications to ensure an appropriate response to an SB0 event, t
2.4 Quality Assurance (QA) and Technical Specifications (TS)
The licensee has identified all equipment to be covered by a QA program but did not explicitly address the applicable QA programs for each item of the 580 equip-ment. Since the majority of the equipment is safety related and some of the equipment is covered by TS, the staff will expect the licensee to review the existing QA programs to determine if they are sufficient for the credited equipment including ADVs while coping with and recovering from an S80.
Recommendation: If the QA programs are insufficient or nonexistent, the staff recommends that the licensee correct them accordingly.
The TS for the 580 equipment are currently being considered generically by the NRC in the context of the Technical Specification Improvement Program and remain an open item at this time. However, the staff would expect that the plant procedures will reflect the appropriate testing and surveillance requirements to ensure the operability of the necessary SB0 equipment, including ADVs. If the staff later determines that a TS re arding the SB0 equipment is warranted, the licensee will be notified of the im lementation requirements.
2.5 EDG Reliability Program The licensee indicated that an EDG reliability program is under development and will be evaluated and adjusted in accordance with the guidance of RG 1.155, Sec-tion 1.2. The staff considers this to be an acceptable commitment for an EDG reliability program.
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6-2.6 Scope of Staff Review The SB0 Rule (10 CFR 50.63) requires licensees to submit a response containing specifically defined information. It also requires utilities to have baseline assumptions, analyses and related information used in their coping evaluation available to NRC. The staff and its contractor (SAIC) did not perform a detailed review of the proposed procedure modifications which are scheduled for later implementation or the modifications that could result from the recommenda-tions documented in this SE. However, based on our review af the licensee's supporting documentation and SB0 plant audit, we have identified the following areas for focus in any followup inspection or assessment that may be undertaken by the NRC to further verify conformance with the SB0 Rule. Additional items may be added as a result of the staff review of a revised SB0 response,
- b. Hardware and procedure modifications,
- c. SB0 procedures in accordance with RG 1.155, Position 3.4, and NUMARC 87-00, Section 4,
- d. Operator staffing and training to follow the identified actions in the SB0 procedures,
- e. Equipment and components required to cope with an SB0 are incorporated in a QA program that meets the guidance of RG 1.155, Appendix A, and
- f. Actions taken pertaining to the specific recommendations noted above in this SE.
3.0 CONCLUSION
Based on the staff's review of SAIC's TER and participation in the SB0 site audit, the staff recommends that the licensee reevaluate the areas of non-conformance with the SB0 guidance identified in this SE. Guidance for this reevaluation and for implementation of staff recommendations is provided in RG 1.155, NUMARC 87-00 and the supplementary guidance (NUMARC 87-00 Supplementary Questions /
Answers; NUMARC 87-00 Major Assumptions) dated December 27, 1989, which was issued to the industry by NUMARC on January 4,1990. A revised response to the SB0 Rule which addresses implementation of the recommendations should be submitted for staff review within 60 days. Subject to an acceptable resolution of the staff recommendations, the issue of conformance to the SB0 Rule remains open at the Crystal River Unit 3 plant.
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4.0 ATTACHMENT 4
1.- SAIC.89/1150, Crystal River Unit 3 Station Blackout Evaluation, July 11, 1990.
Dated: August 23, 1990 Principal Contributor:
P. Gill
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