ML20134N706
| ML20134N706 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/19/1997 |
| From: | Roe J NRC (Affiliation Not Assigned) |
| To: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| NOED-97-6-004, NOED-97-6-4, TAC-M97963, NUDOCS 9702240381 | |
| Download: ML20134N706 (5) | |
Text
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February 19, 1997 Mr. Harold B. Ray Executive Vice President Southern California Edison Company San Onofre Nuclear Generating Station P. O. Box 128 San Clemente, California 92674-0128
SUBJECT:
NOTICE OF ENFORCEMENT DISCRETION FOR SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 3 (NOED 97-06-004) (TAC NO. M97963)
Dear Mr. Ray:
By letter dated February 16, 1997, Southern California Edison (SCE or the licensee) requested the NRC exercise discretion not to enforce compliance with the actions required in Surveillance Requirement (SR) 3.3.5.6 of Technical Specification (TS) 3.3.5, " Engineered Safety Features Actuation System (ESFAS)
Instrumentation," for San Onofre Nuclear Generating Station (SONGS), Unit 3, regarding performance of response time testing of ESFAS subgroup relays. The letter documented information previously discussed with the NRC in a telephone conversation on February 15, 1997, that began at 12:00 noon Eastern Standard Time (EST). During this telephone conversation, the licensee stated that the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed by SR 3.0.3 would expire at 4:00 pm EST on February 15, 1997, which would require the unit to begin shutting down in accordance with Actions D and E of Limiting Condition for Operation (LCO) 3.3.5.
You requested that a Notice of Enforcement Discretion (N0ED) be issued pursuant to the NRC's policy regarding exercise of discretion for an operating facility, set out in Section VII.c, of the " General Statement of Policy and Procedures for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600. This enforcement discretion is to be effective for a 7-day period for those subgroup relays that can be safely tested at power, and for the period of time needed for the NRC to process a TS amendment on an exigent basis for the remaining subgroup relays. This TS amendment would defer implementation of SR 3.3.5.6 to no later than the SONGS Unit 3 Cycle 9 refueling outage (currently scheduled to begin on April 12, 1997). The licensee committed, in its letter dated February 16, 1997, to test the subgroup relays in accordance with SR 3.3.5.6 in the event of a planned or unplanned shutdown of Unit 3 before the refueling outage.
The need for this N0ED request results from a misinterpretation by the
/ O licensee of the TS requirements for testing the subgroup relays in the ESFAS circuitry. This misinterpretation may have originated in 1983 when the licensee used a bounding response time evaluation (which resulted in an ng
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assumed relay response time of 0.3 seconds) in lieu of including the subgroup I/f I
relays in the periodic tests conducted to satisfy the engineered safety features (ESF) response time surveillance requirement (SR 3.3.5.6).
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Mr. Harold B. Ray February 19, 1997 3.
This error was discovered by the licensee as a result of the intensive review effort of the TS requirements initiated after an N0ED was granted on January 13, 1997. As a result of this effort, the licensee concluded that SR 3.3.5.6 requires the subgroup relays be included in the ESF response time surveillances performed every 24 months on a staggered test basis. The licensee contends that the new definition of ESF response time in the improved TS implemented on August 5,1996, added the requirement to test the subgroup relays. However, the staff believes that the bounding response time evaluation developed in 1983 may not have been a valid method of meeting the original TS requirements, and that the relay subgroups may have required specific response time testing to satisfy the original TS requirements. This position is supported by the Bases of the previous TS, which state that the relays need to be included in the periodic tests to comply with the ESF response time surveillance requirement.
There are 85 ESF subgroup relays in San Onofre Unit 3 that require response time testing to comply with SR 3.3.5.6.
ESF response time data is available for 8 subgroup relays, and the licensee will test, before 3:43 pm EST Tebruary i
22,1997 (i.e., 7 days from the granting of the N0ED), all subgroup raays (a majority of the untested relays) that can be safely tested while the unit is at power. The remaining subgroup relays will be tested during the next Unit 3 shutdown, and no later than during the upcoming refueling outage (currently scheduled to begin on April 12,1997).
The licensee requested the staff exercise enforcement discretion for compliance with SR 3.3.5.6 for 7 days for those subgroup relays that can be safely tested during power operation, and until the next Unit 3 shutdown for the remaining subgroup relays affected by SR 3.3.5.6.
The licensee's safety rationale for this request is that the operational history, bounding response time evaluation, margins available in actual ESF response time testing verses TS values, and the inherent reliability of the subgroup relays provide adequate assurance that the relays are operable and fully capable of performing their intended safety function.
The enforcement discretion would avoid an undesirable transient associated with an unnecessary plant shutdown and thus minimize potential safety consequences and operational risks associated with such action.
The staff evaluated the safety consequences of allowing Unit 3 to continue operation until its next plant shutdown without compliance with SR 3.3.5.6 along with other mitigating information that is available, and compared this to the small, but measurable amount of risk associated with an unnecessary plant shutdown. The staff concluded that the option that resulted in the minimum safety impact was the licensee's proposed option of allowing 7 days to perform the required surveillance for the majority of the subgroup relays, and allow the surveillances for the remaining subgroup relays to be postponed until the upcoming refueling outage. The licensee indicated their confidence that the affected subgroup relays are operable since no failures of the Potter Brumfield Motor Driven Relays have occurred at San Onofre since the improved relays were installed in the two units during the 1989-1993 time period.
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Mr. Harold B. Ray February 19, 1997 i
Further, the licensee has performed response time testing on a number of San Onofre Unit 2 and 3 subgroup relays since entering SR 3.0.3 on February 14, j
1997. The measured test results for each subgroup relay are bounded by the assumed response allowance of 0.300 seconds established by the licensee in 4
1983.
In addition, the licensee den.onstrated that large margins are available between the allowed TS ESF response times (established from design basis accident conditions) and actual ESF response times obtained from surveillance tests of record.
i The staff applied the criteria similar to those in 10 CFR 50.91 to verify that the emergency condition leading to the request for enforcement discretion was unavoidable. The staff concluded that the identification of this problem was a result of the intensive team review effort that began in January 1997, and i
that it was likely the direct result of a decision the licensee made in 1983.
The staff considers this issue to be unavoidable because-a significant level of effort on the part of the licensee was required to uncover the error.
If the error occurred during the TS conversion process, as the licensee claims, the staff would also consider it to be unavoidable, based on the level of i
effort performed during the TS conversion process as reported by the licensee in its February 15, 1997, letter.
In this letter, the licensee stated that a multi-disciplinary implementation team was formed to ensure that the new TS were properly implemented in the plant procedures, and that over 900 i
procedures required changes to reflect the new TS requirements, i
The staff agrees with the licensee that an unnecessary plant shutdown constitutes an undesirsble transient involving a small amount of risk and, therefore, considers the option of requiring a shutdown specifically to perform SR 3.3.5.6 to be unwarranted. Criterion 1 of Scction 8 of the j
Enforcement Policy states in part that, "For an operating plant, the NOED is intended to (a) avo: ' undesirable transients as a result of forcing compliance t
with the license condition and, thus, minimize potential safety consequences and operational risks...."
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On the basis of the staff's evaluation of your request, the staff has concluded that an N0ED is warranted because we are clearly satisfied that this action involves minimal or no safety impact and has no adverse radiological j
impact on public health and safety. Therefore, it is our intention to i
exercise discretion not to enforce compliance with LCO 3.3.5 for the period from 3:43 pm EST February 15, 1997, until (1) 3:43 pm EST February 22, 1997, i
for those subgroup relays that can be safely response time tested during Unit 3 Jower operation, and (2) issuance of a license amendment for the remaining su qroup relays governed by SR 3.3.5.6.
The staff will process your TS amendment request received on February 18, 1997, to resolve this issue on an exigent basis. This letter documents our telephone conversation on February 15, 1997, when we orally issued this notice of enforcement discretion.
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'Mr. Harold B. Ray '
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February 19, 1997 However, as stated in the Enforcement Policy, action will normally be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this N0ED was necessary.
Sincerely, Original Signed By El'.nor G. Adensam 1
)<u Jack W. Roe, D' rector O
Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-362 cc:
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I Mr. Harold B. Ray February 19, 1997 I
cc:
Mr. R. W. Krieger, Vice President Resident Inspector / San Onofre NPS Southern California Edison Company c/o U.S. Nuclear Regulatory Commission San Onofre Nuclear Generating Station Post Office Box 4329 P. O. Box 128 San Clemente, California 92674 San Clemente, California 92674-0128 Mayor Chairman, Board of Supervisors City of San Clos mte County of San Diego 100 Avenida Pres'dio 1600 Pccific Highway, Room 335 San Clemente, Ci ifornia 92672 San Dia10, California 92101 Alan R. Watts, Esq.
Woodruff, Spradlin & Smart 701 S. Parker St. No. 7000 Orange, California 92668-4702 Mr. Sherwin Harris Resource Project Manager Public Utilities Department City of Riverside 3900 Main Street Riverside, California 92522 Dr. Harvey Collins, Chief Division of Drinking Water and Environmental Management California Department of Health Services P. O. Box 942732 Sacramento, California 94234-7320 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower & Pavilion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Mr. Terry Winter Manager, Power Operations San Diego Gas & Electric Company P.O. Box 1831 San Diego, California 92112-4150 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94234 4