ML18101A563
| ML18101A563 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 02/22/1995 |
| From: | Cooper R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Labruna S Public Service Enterprise Group |
| References | |
| NOED-95-1-001, NOED-95-1-1, NUDOCS 9502280414 | |
| Download: ML18101A563 (6) | |
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February 22, 1995 NOED 95-I-OOI Mr. Stanley LaBruna Vice President-Nuclear Engineering Nuclear Business Unit Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038-0236
SUBJECT:
NOTICE OF ENFORCEMENT DISCRETION FOR SALEM UNITS I AND 2, RELATIVE TO REACTOR TRIP AND ENGINEERED SAFETY FEATURE INSTRUMENTATION SYSTEMS
Dear Mr. LaBruna:
On February I, I995, a plant having a similar design to the Salem facility identified a condition in which a fault in the Solid State Protection System's (SSPS) non-safety related input circuitry for the turbine stop valve limit switches, auto-stop oil pressure switches, or reactor coolant pump breaker position could render a train of SSPS inoperable, since the inputs are not electrically isolated from the safety related portion of SSPS.
Upon subsequent analysis, Public Service Electric and Gas Company (the licensee) determined that a potential vulnerability of a similar nature existed for the Salem facilities. A postulated steam line break or seismic event at the Salem facility could affect these specific inputs and cause an electrical short circuit. Such a short may have the potential to cause failure of the power supplies for the logic circuitry of one or both trains of SSPS since the IE portion of the system is not electrically isolated from the non-IE inputs.
Consequently, the SSPS was declared inoperable although the system remained available.
Accordingly, plant shutdown of both Salem units commenced as required by Technical Specification 3.0.3. At that time Unit I was at IOO%
power (Mode I), and Unit 2 was at 0.5% power (Mode 2).
At about I2:30 a.m. on February 2, I995, members of the Salem operations department, the Nuclear Business Unit engineering organization, and you initiated a telephone conference with me and other members of the NRC staff.
The conference call was completed at 2:30 a.m., February 2 after extensive discussion.
In that conference you verbally requested enforcement discretion from the provisions of the Salem I and 2 Technical Specifications 3/4.3.I, Action IO; 3/4.3.2, Table 3.3-3, Action I3; and 3/4.3.I, Action I. The most limiting condition of operation required that two channels of SSPS be operable in Modes I and 2, and that Engineered Safety Feature Actuation System Instrumentation be operable in Modes I, 2, 3, and 4.
With one channel inoperable, the most limiting action required restoration of the affected channel within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, or be in Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
At the time Salem Unit I was at 60%
power and proceeding to an orderly shutdown as required by Technical Specification 3.0.3.
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2 Accordingly, you requested enforcement discretion to permit continued operation of each unit at their previous power levels (i.e., Unit I in Mode I, at 100% power; and Unit 2 in Mode 2, at about 0.5% power) while actively pursuing a design change to correct vulnerabilities that had the potential to affect reactor trip system instrumentation and Safety Injection input through the SSPS.
The purpose of your verbal request for enforcement discretion was to allow exit from Technical Specification 3.0.3, and extend the applicable technical specification action time to 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> in order to permit the completion of the design change.
Your verbal request included a conunitment to provide a written submittal of the justification for your request by February 4, 1995.
During the telephone conference on February 2, your staff described their assessment of this potential vulnerability, the bounding worst case scenarios and event initiators that prevailed, and the proposed design modification that would mitigate the consequences of the postulated events by adding fused protection between aforementioned non-safety related circuitry and the safety related SSPS power supplies.
Your staff indicated that the design change was planned so that only one train of SSPS would be modified at a time. All other SSPS trains would be maintained as available. All ESF equipment was confirmed operable, and no planned maintenance was scheduled for any ESF equipment while the design change. was in progress.
To further assure against an inadvertent plant trip as a result of design change activities, you indicated the intent to close the applicable bypass breakers to support modification activities on each of the SSPS trains, for a period not to exceed 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> in each instance.
As a safety justification for this proposed action, your staff cited that the risk analysis of increased core damage for such action was determined to be less than the risk of shutting down each plant manually.
Other compensatory actions included the issuance of directions and guidance to operators to sensitize them to the existing plant conditions and postulated steam line break scenarios, the maintenance of steady state conditions during the performance of the design change on Unit 1, and the maintenanc~ of Mode 2 with Main Steam Isolation Valve closed on Unit 2.
You also indicated that a special crew was trained on the performance of this modification, and that design change performance was verified and validated on a spare SSPS cabinet at the Nuclear Training Simulator.
Your request for a 96 hour0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> extension of the action statement was based on expected time to complete the design change, including preparation, implementation, post-modification testing, and restoration activities.
You further indicated that your staff reviewed the changes in plant configuration in accordance with 10 CFR 50.59 and determined that an unreviewed safety questi~n was not involved, and that the action did not involve a significant increase in the probability or consequences of an
Mr. Stanley LaBruna 3
accident as previously evaluated.
You confirmed that the design change and the bases for your request for enforcement discretion was approved by your Station Operations Review Committee.
In light of our recent SALP assessment of your staff's performance in the Operations, Maintenance, and Engineering functional areas, the staff considered the ability of your staff to safely design and install the modifications that were discussed during the telephone call.
We specifically considered the compensatory measures and other actions you had taken or planned during the period of enforcement discretion and the modification activities that you would be conducting in relation to these three areas that previously exhibited performance weaknesses.
Our evaluation concluded that you:
(1) took aggressive action to determine the impact of the SSPS vulnerability on the operability of the system since you first became aware of it on February 1, 1995; (2) issued directions and provided guidance to the operators on the specific plant conditions and, in particular, procedures that would apply in response to the failure of the SSPS, should it actually occur; (3) reduced the impact of inadvertent errors causing a plant transient during installation of the modification on each train of SSPS by maintaining the respective train's reactor trip bypass breaker closed; (4) trained a special crew on the installation of the modification; and, (5) verified the design change on a spare SSPS cabinet prior to installation.
In our view, your actions mitigated the likelihood of a personnel error causing a plant transient or other adverse plant condition during the period of enforcement discretion and mitigated the risk of a poor response by operators to such a transient, should it occur.
To confirm the conclusions we reached, we decided to provide additional inspection coverage of the modification design and its installation.
In view of these actions and assessment, and with recognition that your staff adopted the same approach and design modification that was previously evaluated and approved by the NRe relative to a similarly designed facility, we verbally approved your request for enforcement discretion, effective 2:30 a.m., February 2, 1995.
At that time, the staff was satisfied that the action involved minimal safety risk and impact, and had no adverse effect on public health and safety. Accordingly, we agreed to exercise enforcement discretion relative to the requirements of the applicable Technical Specifications for the period between 2:30 a.m. February 2 and 2:30 a.m. February 6, 1995.
Subsequently, on February 3, upon actual implementation of the design change on a Unit 1 SSPS train, the unit experienced an unexpected trip of the redundant 15 voe logic power supply, when action was taken to de-energize the primary 15 VOe logic power supply. Consequently, design change activities were suspended while your staff attempted to di~gnose and troubleshoot the cause of the fault. Though your staff made a comprehensive effort to understand the nature of the power supply problem and effect resolution, no firm conclusion was reached during the shift.
At 4:20 p.m., on February 3, after consultation with senior NRC management, Region I informed you that the NRe was rescinding the enforcement discretion since the emerging circumstances involving power supply problems adversely affected the staff's basis for granting enforcement discretion. Specifically,
f Mr. Stanley LaBruna 4
the unexpected response of the SSPS power supplies raised questions regarding the reliability of the SSPS function and thus, negatively affected our belief that the SSPS was otherwise operable despite the originally discussed design issue. Consequently, you committed to adhere to the requirements of Technical Specification 3.0.3. Accordingly, since SSPS was considered inoperable for both units, your staff took immediate action to place both units in Mode 5 (Cold Shutdown) in accordance with the specification.
Notwithstanding this action, we acknowledge your written submittal for enforcement discretion dated February 3, 1995.
From our review, it appears that your submittal was complete and documented sufficient bases to support our previous verbal approval.
In accordance with NRC policy, your submittal and this letter will be placed in the Public Document Room.
cc:
J. J. Hagan, Vice President-Operations ORIGINAL SIGNED BY:
Richard W. Cooper,11, Director Division of Reactor Projects C. Schaefer, External Operations - Nuclear, Delmarva Power & Light Co.
R. Burricelli, General Manager - Information Systems & External Affairs J. Summers, General Manager - Salem Operations J. Benjamin, Director - Quality Assurance & Safety Review F. Thomson, Manager, Licensing and Regulation R. Kankus, Joint Owner Affairs A. Tapert, Program Administrator R. Fryling, Jr., Esquire M. Wetterhahn, Esquire P. J. Curham, Manager, Joint Generation Department, Atlantic Electric Company Consumer Advocate, Office of Consumer Advocate William Conklin, Public Safety Consultant, Lower Alloways Creek Township Public Service Commission of Maryland D. Screnci, PAO (2)
PUBLIC Nuclear Safety Information Center (NSIC)
NRC Resident Inspector State of New Jersey State of Delaware
OFFICE NAME DATE Mr. Stanley LaBruna bee:
R. Zimmerman, NRR S. Varga, NRR A. Thadani, NRR J. Stolz, NRR R. Cooper, DRP J. Lieberman, OE J. White, DRP C. Marschall, DRP (Salem)
D. Holody, Enf. Coord.
DOCUMENT NAME:
g:\\ ranch2\\noed.sal To racelw a copy of lndicale in the box: "C" = Copy without attachment/enclosure attachmentjenclosur copy OFFICE RI:DRP NAME RCoo er DATE 2/ /95 OFFICIAL RECORD COPY
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Mr. Stanley LaBruna bee:
R. Zimmerman, NRR S. Varga, NRR A. Thadani, NRR J. Stolz, NRR R. Cooper, DRP J. Lieberman, OE J. White, DRP C. Marschall, DRP (Salem)
D. Holody, Enf. Coord.
J. Wiggins, DRS NOED File DOCUMENT NAME:
g:\\branch2\\noed.sal To receive a copy of this document, indicate in the box: "C' attachment/enclosure "N' = No copy OFFICE RI:DRP*
NRR NAME JWhite DATE 2/ /95
- See Previous Concurrence Page 5
py without attachmentf enclosure "E' = Copy with