ML16342C828
| ML16342C828 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/06/1995 |
| From: | Callan L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| NOED-95-4-001, NOED-95-4-1, NUDOCS 9502150025 | |
| Download: ML16342C828 (12) | |
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UN IT E 0 STATE6 UC LEAR R EG ULATORY COMMISS I R EG ION IV 611 RYAN PLAZA ORIVE, SUITE 400 ARLINGTON,TEXAS 76011 8064 FEB -6 l995 Pacific Gas and Electric Company Nuclear Power Generation, B14A ATTN:
Gregory H. Rueger, Senior Vice President and General Hanager Nuclear Power Generation Bus. Unit 77 Beale Street, Room 1451 P.O.
Box 770000 San Francisco, California 94177
SUBJECT:
NOTICE OF ENFORCEHENT DISCRETION FOR PACIFIC GAS AND ELECTRIC COHPANY REGARDING DIABLO CANYON UNITS 1
AND 2 By letter dated February 2,
- 1995, you requested that the NRC exercise discretion not to enforce compliance with the actions required in Technical Specifications (TS) 3/4.3. 1, "Reactor Trip System Instrumentation,"
and 3/4 '.2, "Engineered Safety Features Actuation System Instrumentation."
That letter documented information previously discussed with the NRC in a telephone conversation on February 1,
1995, at 10:25 a.m.
(PST).
You stated that, on February 1,
- 1995, at 10:25 a.m.
(PST) the plants would not be in compliance with TS 3/4.3.2, which requires that operation with one train of the solid state protection system inoperable may continue for no longer that 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
You entered the action statement for this TS at 10;25 a.m.
(PST) on February 1,
1995.
Additionally, in order to correct the deficiency, enforcement discretion was requested to allow each reactor trip breaker to be bypassed for longer than the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> allowed by Action Statement 10 of TS 3/4.3.1.
You requested that a Notice of Enforcement Discretion (HOED) be issued and be effective for the period expiring at 12 noon (PST) on February 5,
1995.
On February 1,
- 1995, you determined that a main steamline break (HSLB) in the turbine building could result in failure of one train of the automatic engineered safety feature function of the solid state protection system (SSPS) as a result of the steam jet striking electrical terminal boxes containing two SSPS instrument channels whose Class -II inputs to the SSPS are not electrically isolated from Class I logic power supplies.
If a single active failure of the instrument AC bus supplying power to the slave relays of the other SSPS train were to occur, both trains of SSPS would be rendered inoperable.
Consequently, no automatic actions would be available to mitigate the consequences of the steam line break, although the reactor would trip on loss of SSPS.
You requested enforcement discretion in order to prevent a
forced shutdown of Diablo Canyon Units 1
and 2 until the SSPS circuitry could be modified to correct the design deficiency.
Your safety justification for the NOED included:
(1) the Westinghouse evaluation of the event concluded that the current FSAR licensing basis for the HSLB core response remained bounding and the'ncreased cooldown had no appreciable effect on pressurized thermal shock risk; (2) acceptable operator responses and acceptable plant responses to the simulator scenario of a loss 9502f50025 950206 PDR ADOCK 05000275 P
~51 I P
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Pacific Gas and Electric Company of both SSPS trains with no operator action; (3) the insignificant increase in core damage frequency during the period that the enforcement discretion is applicable; (4) the implementation of a design
- change, as corrective action, to electrically isolate the Class II SSPS inputs from th'e Class I logic power supplies in both units, by a crew specially=trained to implement the design change; and (5) that no unreviewed safety question and no significant hazard exists.
To provide additional assurance that the public health and safety would not be adversely affected by the requested enforcement discretion, you implemented the following compensatory measures:
(1) the design change will be performed on only one train of SSPS at any given time; (2) train-related maintenance and surveillance testing will be suspended until the implementation of the design change; (3) high risk plant evolutions will be avoided; (4) the preparation of an operations shift order describing this conditio~'nd the proper implementation of the emergency procedure for responding to an J1SLB that affects the SSPS; (5) the prohibition of voluntary power curtailments in a unit until the design change is implemented; and (6) restricting activities on the 140 foot elevation of the turbine deck, which could result in damage to -the steam lines, until the implementation of the design change is complete.
The NRC staff has evaluated your safety justification assertions and compensatory measures and concluded that the environment and public health and safety would not be adversely affected and no unreviewed safety question or significant hazard exits as a'esult of the implementation of the NOED.
On the basis of the staff's evaluation of your request, including the compensatory measures described
- above, the staff has concluded that the exercise of enforcement discretion is warranted because we are clearly satisfied that this action involves minimal or no safety impact and has no adverse impact on public health and safety.
Therefore, it is our intention to exercise discretion not to enforce compliance with TS 3/4.3. 1 and 3/4.3.2 for the design deficiency with the SSPS during the period from 11:25 a.m.
(PST),
February 1,
1995, until 12 noon (PST),
February 5,
1995.
This letter documents our telephone conversation on February 1,
1995, at 11:25 a.m.
(PST) when we orally issued this NOED.
We understand that the condition causing this NOED was corrected by you on both units, causing you to exit from TS 3/4.3. 1 and 3/4.3.2 and this NOED on February 3, 1995, at approximately 1 p.m.
(PST).
Pacific Gas and Electric Company
- However, as stated in Appendix C to 10 CFR Part 2, enforcement action will normally be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this discretion was used.
Sincerely, Dockets:
50-275 50-323 Licenses:
DPR-80 DPR-82 NOED:
95-4-001 Ca an Reg nal Administrator CC:
Sierra Club California ATTN:
Dr. Richard Ferguson Energy Chair 6715 Rocky Canyon
- Creston, California 93432 San Luis Obispo Mothers for Peace ATTN:
Hs.
Nancy Culver P.O.
Box 164 Pismo Beach, California 93448 Ms. Jacquelyn C. Wheeler P.O.
Box 164 Pismo Beach,, California 93448 The County Telegram Tribune ATTN:
Managing Editor 1321 Johnson Avenue P.O.
Box 112 San Luis Obispo, California 93406 San Luis Obispo County Board of Supervisors ATTN:
Chairman Room 370 County Government Center San Luis Obispo, California 93408
Pacific Gas and Electric Company California Public Utilities Commission ATTN:
Hr. Truman Burns)Hr. Robert Kinosian 505 Van Ness, Rm.
4102 San Francisco, California 94102 Diablo Canyon Independent Safety Committee Attn:
Robert R. Wellington, Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940 Radiologic Health Branch State Department of Health Services ATTN:
Hr. Steve Hsu P.O.
Box 942732 Sacramento, California 94234 State of California ATTN:
Hr. Peter H. Kaufman Deputy Attorney General 110 West A Street, Suite 700 San Diego, California 92101 Pacific Gas and Electric Company ATTN:
Christopher J.
- Warner, Esq.
P.O.
Box 7442 San Francisco, California 94120 Diablo Canyon Nuclear Power Plant ATTN:
Warren H. Fujimoto, Vice President and Plant Manager P.O.
Box 56 Avila Beach, California 93424
Pacific Gas and Electric Company FEB -6 1995 bcc to DMB (IE51) bcc distrib.
by RIV:
L. J. Callan DRSS-FIPB Branch Chief (DRP/E, WCFO)
RIV File Leah Tremper (OC/LFDCB, HS:
TWFN 9E10)
R.
Zimmerman, NRR (HS:
12G18)
W. Russell, NRR (MS:
12G18)
J.
- Roe, NRR (MS:
13E4)
Technical Assistant, DRP I/II, NRR A. Thadani, NRR (HS:
12G18)
T. quay, NRR (HS:
13E16)
Resident Inspector HIS System Sr. Project Inspector (DRP/E, WCFO)
Branch Chief (DRP/TSS)
B. Henderson (PAO, WCFO)
L. Thomas, DRP (NOED Tracking File)
PDR LPDR J,
Lieberman, OE (MS:
7H5)
M. Miller, NRR (MS:
4D28)
To receive copy cf document, indicate in box: "C" = Copy without enclosures "E" ~ Copy with enclosures "N" ~ N copy C:DRPgE NRR DD:DRP D:DRP ~
DRA FKirsch;df quay~
JEDyer 2/C /95 ~~A~
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Pacific Gas and Electric Company FEB -6 1995 bcc to DHB (IE51) bcc distrib.
by RIV:
L. J. Callan ORSS-FIPB Branch Chief (DRP/E, WCFO)
RIV File Leah Tremper,(OC/LFDCB, HS:
TWFN 9E10)
R.
Zimmerman, NRR (HS:
12G18)
W. Russell, NRR (MS:
12G18)
J.
- Roe, NRR (HS:
13E4)
Technical Assistant, DRP I/II, NRR A. Thadani, NRR (HS:
12G18)
T.
- Quay, NRR (HS:
13E16)
Resident Inspector HIS System Sr. Project Inspector (DRP/E, WCFO)
Branch Chief (DRP/TSS)
B. Henderson (PAO, WCFO)
L. Thomas, DRP (NOED Tracking File)
PDR LPDR J.
Lieberman, OE (HS:
7H5)
H. Hiller, NRR (MS:
4028)
To receive copy of document, indicate in box: "C
~ Copy without enclosures "E
~ Copy with enclosures "N" ~ N copy NRR C:DRP~tE Quay~
FKirsch;df 2/6 /95 ~1@~
2/t', /95 DD:ORP JEOyer 2/6 /95 0:DRP ABBe h
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