ML20203C391
| ML20203C391 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/20/1998 |
| From: | Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-98049, NUDOCS 9802250175 | |
| Download: ML20203C391 (5) | |
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FE Log # TXX 98049 C-File # 10010 916 (3/4.8) 7t/ELECTR/C Ref. # NUREG 1600 c ui.e w February 20, 1998 Senior \\1ce President
& PrincipalNuclear Oficer U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
C0HANCHE PEAK STEAM ELECTRIC STATION (CPSES)
UNITS 1 AND 2 DOCKET NUMBERS 50 445 AND 50 446 ENFORCEMENT DISCRETION FOR A.C. SOURCES. OPERATING REF:
1.
NUREG 1600. " General Statenent of Policy and Procedures for NRC Enforcement Actions,", dated June 1995 i
2.
NRC Inspection Manual, Part 9900 " Operations Enforcement Discretion." dated November 2. 1995 Gentleeen:
In accordance with the guidance provided by reference 1. Texas Utilities Electric Company (TV Electric) requests that the Nuclear Regulatory Commission (NRC) exercise enforcement discretion to allow CPSES Units 1 and 2 to continue operation in Mode 1, 2. 3. or 4 without having demonstrated tha load shedding feature of MCC XEB4 3.
Without the requested enforcement discretion, compliance with CPSES Technical Specification 3.8.1.1. "A.C. Sources. Operating," could require that TV Electric shut down both units to COLD SHUTDOWN. HDDE 5.
The referenced section of the NRC Inspection Manual (reference 2) provides guidance on the information to be included in a request for enforcement discretion. The sections below are arranged to correspond to that guidance.
- 1. RE0VIREMENT/RE00EST:
Limiting Condition for Operation (LCO) 3.8.1.1 requires in part, that certain A.C. electrical sources be OPERABLE. including two separate and f
g independent diesel generators, in Modes 1. 2. 3. and 4.
With either diesel generator inoperable, the inoperable diesel generator must be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY hU[~
within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in 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 /> 1
(ACTION b.).
In addition, with either diesel generator inoperable and a system, subsystem.-train component or device that depends on the remaining OPERABLE diesel generator as a source of emergency power inoperable, either the diesel generator or the other inoperable equipment must be restored to OPERABLE within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least HOT STANDBY
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TXX 98049 Page 2 of 5 j
within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in 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 /> (ACTION d.).
TU Electric requests that the NRC exercise enforcement discretion to not enforce compliance with the Surveillance Requirements of TS 4.8.1.1.2f)4)a) and 4.8.1.1.2f)6)a) for load shedding of HCL XEB4 3.
- 2. CIRCUHSTANCES:
While performing a review nf surveillance procedures in accordance with U.S. NRC Generic Letter 96 01. it was determined that the surveillance procedure for Surveillance Requirement 4.8.1.1.2f)4)a) was deficient in that the load shedding of one electrical bus on each unit had not previously been tested.
The surve111ence requires that upon t. loss of-offsite power, the emergency busses de energize and load shedding occurs.
The current procedures for the train B diesel generator (DG)for both CPSES Units 1 and 2 does not require confirmation that bus XEB4 3 load sheds for Units 1 and 2 respectively.
This is a common bus that can be supplied froin either Unit 1 or Unit 2.
TU Electric confirmed that failure to load shed these busses would not result in the diesel generators being inoperable as both diesels have sufficient reserve ca)acity to emergency start and perform their safety functions with these )usses loaded at time zero in the diesel generator loading sequence.
TV Electric believes that this specification only requires testing of the loads which are required to be load rhed to allow the DG to perform its specified safety functions.
Because the diesel generators remain capable of performing their specified safety functions without the load shed of this bus. TV Electric concluded that the surveillance had been met.
In sut equent discussions with NRR. the NRC staff ex)ressed the opinion that, even though the staff did not see a safety pro)1em or issue. CPSES was not in literal compliance with these Surveillance Requirements.
Based on the feedback received from the NRC staff. TV Electric chose the conservative action of declaring the Surveillance "equirements as missed and invoking the requirements of Technicel Specification 4.0.3 for a missed surveillance.
- 3. SAFETY SIGNIFICANCE AND POTENTIAL CONSE0VENCES:
The safety function of the A.C. Sources is to ensure that sufficient power will be available to supply the safety related equipment required for: (1) the safe shutdown of the facility, and (2) the mitigation and control of accident conditions within the facility.
The function of the Surveillance Requirement of concern is to demonstrate that for a start of the diesel generators, the emergency busses will de energize and sufficient load will be shed, to allow the diesel generator to start, connect to the emergency busses and load.
Because the busses in question can be loaded on the diesel gererator at time zero of the loading sequence without affecting the ability of the diesel generator to properly start, connect to the emergency bus and load thereby performing its safety function.
Failure to test the load shed feature with respect to this single load has no impact on safety.
The potential consequences resulting from a coincident i
TXX 98049 Page 3 of 5 j
shutdown of both units of CPSES and the possible perturbations induced into the A.C. grid clearly are not warranted. As shown above, no consequences of continued operation in the current condition are evident.
- 4. UNREVIEWED SAFETY OUESTION / NO SIGNIFICANT HAZARDS CONSIDERATION:
TU Electric has considered the criteria for assessing the potential of creating an unreviewed safety question or a significant hazards consideration with the exerci ing of enforcement discretion.
In evaluating if discretion in enforcement constitutes a significant hazard the criteria of 10CFR50.92(c) is discussed below:
1.
Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?
The only potential impact of operating without having demonstrated the load shedding feature of HCC XE34 3 is the potential that tha train B DG for either CPSES Unit 1 or Unit 2 will not be able to perform its safety function following a postulated accident or event. TV Electric has evaluated the potential load added to the DGs if this bus does not shed and has concluded that the DGs remain fully capable of performing their safety function. As a Nsult, there in no significant increase in the probability or consequences of an accident previously evaluated.
2.
Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?
Operation without having tested the load shedding feature of bus XEB4 3 does not effect the operation or design of the Units and therefore cannot create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
Do the proposed changes involve a significant reduction in a margin of safety?
Because the diesel generators remain fully capable of performing their safety functions without having demonstrated the load shedding 7eature of HCC XEB4 3, there is no significant reduction in a margin of safety.
TV Electric has performed a safety evaluation, and has determined, in accordance with 10 CFR 50.59 that continued operation without having demonstrated the load shedding feature of HCC XEB4 3 does not constitute an unreviewed safety question.
In summary, using 10CFR 50.59 and 10CFR50,92 TU Electric has determined that operation without having demonstrated-the load shedding feature of bus XEB4 3 does not constitute an unreviewed safety question nor a significant hazard consideration.
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- 5. ENVIRONMENTAL CONSEQUENCES:
l The request only involves normal operatien of the plant. These activities are limited to the )lant and will not result in any unplanned releases that could impact tie environment.
- 6. COMPENSATORY ACTIONS:
No compensatory actions or design changes beyond the engineering evaluation which showed that the busses do not need to be load shed, are required.
- 7. DURATION:
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The requested duration is based upon the time required for the NRC to process a proposed change to the technical specifications. The requested duration is to commence upon approval of this enforcement discretion 4
request and to expire upon disposition of the proposed license amendment.
l
- 8. 50RC REVIEW:
This activity has been reviewed and approved by the Station Operations Review Committee-(50RC).
- 9. CRITERIA FOR EXERCISING EhFORCEMENT DISCRETION:
Reference 2. section B item 1 provides the criteria for exercising enforcement discretion for an operating plant as follows:
For an operating plant, the NOED is intended to (a) avoid undesirable transients as a result of forcing compliance with the license condition and, thus minimize potential safety consequences and operational risk or (b) eliminate testing inspection, or system realignment that is inappropriate for the prticular plant conditions.
This criteria reflects the'NRC's policy as provided in reference 1.
Initiating a two unit shutdown to comply with the subject technical specification would subject CPSES to an undesirable transient which poses greater safety consequences than continued operation with the load shedding feature untested.
- 10. PROPOSED TECHNICAL SPECIFICATION CHANGES:
4 A separate license amendment request (LAR) will be submitted by March 9, 1998, under a different letter. This LAR will request a temporary Technical Specification change which removes the requirement to demonstrate the load shedding feature of HCC XEB4 3 as part of SRs 4.8.1.1.2f)4)a) and 4.8.1.1.2f)6)a) until plant startup subsequent to the next refueling outage for each respective unit.
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- 11. APPROVED LINE ITEM IMPROVEMENTS:
Prior adoption of a) proved line item improvements to the Technical Specifications or tle improv(;d Standard Cechnical Specifications would not have obviated the need for this enforcement discretion request.
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- 12. ADDITIONAL INFORMATION RE0 VESTED BY THE NRC STAFF; The NRC staff has requested no additional information.
3 CONCLUSION;.
TV Electric requests the NRC grant the requested enforcement discretion to allow CPSES Units 1 and 2 to continue to operate while the NRC processes a proposed chango to the technical specifications.
If there is a significant change in the circumstances associated with this exercising of enforcement discretion. TU Electric will notify the NRC. A response is requested by 3:30 pm Central Standard Time on February 20, 1998.
This communication contains the following new commitment which will bt completed as noted:
CDF Number Commitment 27125 A separate-license amendment request (LAR) will be r
submitted by March 9. 1998, under a different letter.
This LAR will request a temporary Technit:a1 Specification change which removes'the requirement to demonse ce the load shedding feature of HCC XEB4 3 as part of SRs 4.8.1.1.2f)4)a) and 4.8.1.1.2f)6)a) until plant startup subsequent to the next refueling outage fc er n respective unit.
o Sincerely, 8, 8. Y$wg.,
l C. L. Terry
@k PA By:
Roger'D. Walker Regulatory Affairs Manager DRW/gp c
Mr. E. W. Herschoff. Region IV Hr. T. J. Polich, NRR Hr. J. I. Tapia. RIV L
CPSES Resident Inspectors
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