ML20096B353
| ML20096B353 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/04/1996 |
| From: | Terry C TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-96009, NUDOCS 9601160212 | |
| Download: ML20096B353 (5) | |
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g Log # TXX 96009 File # 10010 916 (3/4.3) 5 Ref. # NUREG 1600 1UELECTRIC January 4, 1996
- c. t
- c. Tmy Group Vice President i
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
UNIT 2 DOCKET NUMBER 50 446 ENFORCEMENT DISCRETION FOR WIDE RANGE RCS TEMPERATURE-Tn REMOTE SHUTDOWN INDICATION FOR ONE RCS LOOP REF:
1.
NUREG 1600, " General Statement of Policy and Procedures for NRC Enforcement Actions," dated June 1995 2.
NRC Inspection Manual Part 9900, " Operations Enforcement Discretion " dated November 2, 1995 Gentlemen:
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 Unit 2 to continue to operate wi the normal Wide Range RCS (Reactor Coolant System)
Temp.(Temperature) Tn h.. note Shutdown Indication for 1 of 4 loops inoperable.
Without the requested enforcement discretion, compliance with CPSES Technical Specification 3.3.3.2.1 would require that TV Electric initiate unnecessary mode changes without a corresponding safety benefit, thus resulting in an unnecessary plant transient and unnecessary system realignments.
4 The referenced section of the NRC Inspection Manual (reference 2) provides I
guidance on the information to be included in a request for enforcement discretion.
The sections below are arranged to correspond to that guidance.
- 1. REOUIREMENT/ REQUEST:
Limiting Condition for Operation (LCO) 3.3.3.2.1, " Remote Shutdown Instrumentation," requires, in part, that one Wide Range RCS Temp. Tn per RCS Loop be OPERABLE in MODES 1, 2, and 3. ACTION Statement "a" requires that an inoperable instrument be restored to OPERABIE status within 7 days or be in at least MODE 4, HOT SHUTDOWN, within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
TU Electric requests that the 7 Jay Allowed Outage Time (A0T) to restore OPERABILITY be extended.
9601160212 960104 PDR ADOCK 05000446 P
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TXX 96009 Page 2 of 5
- 2. CIRCUMSTANCES:
On December 31,1995, at 2:10 a.m. the Wide Range RCS Temp. Tn for one RCS Loop was discovered to be inoperable. Troubleshooting efforts indicate a ground.
Location of the ground has been isolated to an area inside i
containment that is normally only accessible during periods of a reactor shutdown.
Radiation levels, temperature and personnel safety considerations preclude further trouble shooting and corrective actions without performing a plant shutdown and a possible cooldown.
CPSES Unit 2 is scheduled to commence a refueling outage on February 22, 1996.
CPSES Unit 2 has no other outages planned during the 7 weeks prior to the scheduled start of the refueling outage.
- 3. SAFETY SIGNIFICANCE AND POTENTIAL CONSEQUENCES:
The subject instrument is part of the CPSES design for shutdown from outside the control room (see CPSES Final Safety Analysis Report (FSAR) section 7.4.1.3).
The Hot Shutdown Panel (HSP) and the Shutdown Transfer Panel (STP) are provided as part of the CPSES unit design for shutdown outside the control room. Wide Range RCS Temperature indications are provided on the HSP for the RCS Loops.
RCS temperature is used for the cooldown of the RCS and for the switch-over to Residual Heat Removal (RHR).
In the unlikely event that shutdown from outside the control room (during the duration of the enforcement discretion) is required, the inoperability of Wide Range Temp. Tn for a single RCS Loop is expected to have no measurable impact on the ability of the operators to safely cooldown the RCS and switch over to RHR.
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The Tn indication is used for monitoring subcooling margin and decreasing temperature during the cooldown.
Steam Generator Pressure is the primary means of temperature control with T, and Tn indication lagging due to response time.
One Tn indication is adequate for the operator to perform a controlled shutdown of the reactor.
The worst case scenario for shutdown from outside the control room is for those instances involving a fire in either the control room or the cable spreading room.
The failed Tn indication is one of two which have been analyzed to remain available for operation at the HSP following a fire per the Fire Safe Shutdown Analysis.
Only two have been analyzed, as only those Steam Generators fed by the Train A Auxiliary Feedwater Pump are used for plant cooldown following a fire.
If this event were to occur during the duration of this N0ED, the operator would retain indication of RCS hot leg temperature from the remaining Tn indication.
In accordance with Standard Review Plan 7.4 " Safe Shutdown Systems" and Branch Technical Position CHEB 9.51 " Guidelines for Fire Protection for Nuclear Power Plants." systems designed to ensure post fire shutdown capability, need not be designed to meet single failure criteria.
For shutdowns other than post fire shutdown, the remaining Tn indicators (3) allow for plant cooldown.
Therefore loss of a single loop Tn indicator should have minimal safety l
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TXX 96009 Page 3 of 5 l
significance with no potential for negative consequences should use of the HSP be required.
- 4. UNREVIEWED SAFETY OUESTION / NO SIGNIFICANT HAZARDS CONSIDERATION:
TV Electric has considered the criteria for assessing the potential of creating an unreviewed safety question or a significant hazards consideration with the exercising of enforcement discretion.
This request for additional A0T in combination with the compensatory actions described below, does not adversely affect the probability or consequences of any previously analyzed accident. Because no modifications are being made to the OPERABLE RCS temperature channels, and having inoperable instrument channels is already allowed by the action statements of the CPSES Technical Specifications, there is no potential for any new type of accident.
As a result, the requested enforcement discretion does not create an unreviewed safety question and does not constitute a significant hazards consideration.
- 5. ENVIRONMENTAL CONSEQUENCES:
The request only involves activities within the plant. These activities and their potential consequences are limited to the plant and will not result in any unplanned release that could impact the environment.
- 6. COMPENSATORY ACTIONS:
Briefings will be held to alert all shift licensed personnel as to the inoperability of this channel. As part of the briefing a discussion will be held on the impact on shutdown from outside the control room.
- 7. DURATION:
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 about 24 days, to commence upon expiration of the existing A0T (2:10 am January 7, 1996) and to expire at 11:59 pm February 1, 1996, or upon disposition of the proposed license amendment.
- 8. SORC REVIEW:
This activity has been reviewed and approved by the Station Operations Review Committee (50RC).
- 9. CRITERIA FOR EXERCISING ENFORCEMENT 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 N0ED is intended to (a) avoid undesirable transients as a result of forcing compliance with the license
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j TXX 96009 Page 4 of 5 condition and, thus minimize potentiel safety consequences and operational risk or (b) eliminate testing, inspection, or system realignment that is inappropriate for the particular plant conditions.
These criteria. reflect the NRC's policy as provided in reference 1.
Initiating a shutdown to comply with the subject technical specification and then, shortly thereafter returning to power when OPERABILITY is restored, would subject CPSES to an undesirable transient.
- 10. PROPOSED TECHNICAL SPECIFICATION CHANGES:
A separate license amendment request, LAR 96 001..is being submitted under a different letter and a copy of the proposed marked up page(s) are attached. This LAR will request a temporary Technical S)ecification change which removes the requirement for the instrument until t1e upcoming Unit 2 refueling outage.
- 11. APPROVED LINE ITEM IMPROVEMENTS:
Prior adoption of approved line item improvements to the Technical Specifications or the improved Standard Technical Specifications (STS) would not have obviated the need for this enforcement discretion request.
The improved STS (NUREG 1431 Rev.1) does allow a 30 day A0T for the equivalent action condition (see specification 3.3.4 Condition A).
TV Electric is in the process of preparing a License Amendment Request to convert to the improved STS and submittal of the request is scheduled for December of 1996. Although the LAR associated with this request for enforcement discretion proposes a temporary change to the technical specifications, the LAR associated with the conversion of the technical specifications will re evaluate the instrumentation requirements for remote shutdown and may propose permanent changes to the technical specifications.
Though a N0ED would still be required under the improved STS, the 30 day A0T and the fact that the ACTION applies for the inoperability of one or more remote shutdown functions indicate a minimal safety impact due to the inoperability of a single temperature indicator on a single RCS Loop for approximately 53 days.
- 12. ADDITIONAL INFORMATION REQUESTED BY THE NRC STAFF:
The NRC staff has requested no additional information.
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CONCLUSION 2 TV Electric requests the NRC grant the requested enforcement discretion to allow Unit 2 to continue to operate while the NRC processes a proposed change to the technical specifications.
If there is a significant change 1
l in the circumstances (e.g., if CDSES Unit 2 entered an unplanned cold l
shutdown for other reasons or additional indications on the HSP become inoperable) associated with this aercising of enforcement discretion, TV Electric will notify the NRC. A response is requested by 2:00 p.m. on January 6, 1996.
I Sincer]y,
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C, L. Ter DRW/gp Attachment c
Mr. L. J. Callan, Region IV Mr. T. J. Polich, NRR Mr. W. D. Johnson, RIV CPSES Resident Inspectors l
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Attachment to TXX 96009 Page 1 of 1 TABLE 3.3 5 REMOTE SHUTDOWN MONITORING INSTRUMENTATION TOTAL NO.
MINIMUM READ 0UT OF CHANNELS INSTRUMENT LOCATION CHANNELS OPERABLE 1.
Neutron Flux Monitors HSP 2
1 2.
Wide Range RCS Temp. T HSP 1/ Loop 1/ Loop e
3.
Wide Range RCS Temp. Tn HSP 1/ Loop 1/ Loop
- 4.
Pressurizer Pressure HSP 1
1 5.
Pressurizer Level HSP 2
1 6.
Steam Generator Pressure HSP 1/SG 1/SG 7.
Steam Generator Level HSP 1/SG 1/SG 8.
Auxiliary Feedwater Flow HSP 2/SG 1/SG Rate to Steam Generator 9.
Condensate Storage Tank Level HSP 2
1 10.
Charging Pump to CVCS HSP 1
1 Charging and RCP Seals -
Flow Indication i
HSP Hot Shutdown Panel
=
=
- r~ 1 ' :: The:: requirements (forf einimum? channels operablelforJWide' Range RCS Temp. Tntremote. shutdown (1ndicationsfor;UnitF2:areirevisedtto,1/Loopffor three'(3)iof:theifourJ(4);RCSiLoopsMThisirevisiorcisStoiremain51nteffect until::CPSESiUnit?2dentersLHODEL4 atithej beginning.Lotthe-lseconddrefueling outage?for;UnitJ2.:
COMANCHE PEAK UNITS 1 AND 2 3/4 3 43 I'
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