ML20211H357
| ML20211H357 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/19/1999 |
| From: | Langenbach J GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1920-99-20438, NUDOCS 9909020073 | |
| Download: ML20211H357 (5) | |
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GPU Nuclear, Inc.
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1 NUCLEAR Post Office Box 480
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Middletown, PA 17051-0480 l
Tennsss1s21 August 19, 1999 1920-99-20438 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Ladies and Gentlemen:
Subject:
Three. Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Response to Request for Additional Information j
Technical Specification Change Request No. 248 Remote Shutdown System This letter provides an itemized response (Attachment) to the NRC's request for additional information dated July 12,1999 regarding TMI-l Technical Specification Change Request No. 248 - Remote Shutdown System, submitted to NRC on October 19,1998.
If any additional information is needed, please contact Mr. David J. Distel, Nuclear Licensing and Regulatory Affairs at (973) 316-7955.
Sincerely, James W. Langenbach '
Vice President and Director, TMI
/DJD Attachment cc: Administrator, Region I TMI-l Senior Project Manager f
OO'f TMI-l Senior Resident Inspector File No. 94056 l
0W07 9909020073 990819 PDR ADOCh 05000289 P
1920-99-20438 METROPOLITAN EDISON COMPANY JERSEY CENTR AL POWER AND LIGHT COMPANY PENNSYLVANIA ELECTRIC COMPANY d/b/a GPU ENERGY l
GPU NUCLEAR, Inc.
Three Mile Island Nuclear Station, Unit I Operating License No. DPR-50 Docket No. 50-289 Technical Specification Change Request No. 248 j
Response to Request for Additional Infom1ation (RAI)
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COMMONWEALTH OF PENNSYVANIA
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COUNTY OF DAUPHIN
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This GPUN Inc. response to the NRC Staff's RAI on Technical Specification Change Request No. 248 is submitted in support of Licensee's request to change Appendix A to Operating License No. DPR-50 for Three Mile Island Nuclear Station, Unit 1. All statements contained in this submittal have been reviewed, and all such statements made and matters set forth there in are true and correct to the best of my knowledge.
BY-(j Vice President anfirector, TMI Sworn and subscribed before me this
/
Day of M,'1999.
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Notary Public
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taitanal Seal Debra S. Kl?ck, Notary Pubuc ludondenyTwp DauptunCounty My conunission Expires July 4. 2(X)2 Member, Penncyvania Association O! Notanes
d Attrchment 1920-99-20438 Page1of3 ATTACHMENT NRC Ouestion No.1:
A review of the TMI-l defmition for hot standby shows that it is different than that of the Standard Technical Specification (STS). In the case of the STS, HOT STANDBY refers to a condition where the reactor is subcritical, in the case of the TMI-l TS, HOT STANDBY is defined as the reactor being critical. The applicability statement needs to use the correspending TMI-l definition that is equivalent to the standard or provide sufficient justification for an alternate definition. None of the TMI-l definitions is equivalent to the B&W STS HOT STANDBY, where the reactor is subcritical and Tavg is greater than or equal to 330 degrees F. The closest is TMI-l's definition of HOT SHUTDOWN, where the reactor is subcritical but temperature is greater than or equal to 525 degrees F. TMI-l TSs have no defined term for when the reactor is subcritical but the temperature is between 200 and 525 degrees F.
Response
The proposed TMI-l Technical Specification Section 3.5.7, Remote Shutdown System, applicability requirements are consistent with the Standard Technical Specifications (STS) 3.3.18 in that the operability requirements apply during Power Operation (STS Mode 1), Startup (STS Mode 7.), and Hot Standby (STS Mode 3). It is recognized that the TMI-l Technical Specification definition for Hot Standby differs in that the reactor is critical and reactor coolant temperature is greater than 525T. TMI-l Technical Specification Section 1.2.11, Heatup-Cooldown Mode defines the plant mode when reactor coolant temperature is between 200T and 525T. However, the reactor is subcritical in this mode since TMI-l Technical Specification Section 3.1.3.1 prohibits reactor criticality below 5257 reactor coolant temperature.
The proposed TMI-l Technical Specification 3.5.7 would apply during all modes of plant operation where the reactor is in a critical condition. The criteria for the TMI-l remote shutdown system is to be able to achieve and maintain Hot Shutdown and subcritical reactivity conditions in the reactor. The scope of the instrumentation functions listed in the proposed TMI-l Technical Specification Table 3.5-4 is those functions necessary to place and maintain the unit in a Hot Shutdown, subcritical condition. Safe shutdown is defined as Hot Shutdown for TMI-l since the reactor is in a subcritical condition. The TMI-l remote shutdown system control and instmmentation functions are required to be operable prior to entering an operating mode where the reactor is critical. Similarly, the Standard Technical Specifications do not apply in the Hot Shutdown or l Cold Shutdown conditions. Since the scope ofcontrols and instrumentation needed to achieve and maintain the defined safe shutdown condition are required to be operable before moving to a mode other than the defined safe shutdown condition, nuclear safety and safe plant operations is ensured. Additionally, the control and instmmentation functions to achieve Cold Shutdown are covered by the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> repair criteria of Appendix R and Generic Letter 81-12, and are not required to be addressed by Technical Specifications. The scope ofinstrumentation and controls necessary to provide alternate shutdown capability for TMI-l was reviewed and approved in NRC letter to GPU Nuclear dated October 19,1989.
Therefore, the difference in the definition ofHot Standby between the TMI-1 Technical Specification and the Standard Technical Specification is not considered significant since the proposed Technical Specification for i
the TMI-l remote shutdown system applies to all plant conditions where the reactor would be in a critical condition. The specified scope of remote shutdown systems controls and instmmentation ensures that the j
F Attichment 1920-99-20438 Page 2 of 3 functions required to achieve and maintain Hot Shutdown conditions, which is the safe shutdown, subcritical condition for TMI-1, are operable. Based on the above, GPU Nuclear believes the proposed TMI-l Technical Specification Section 3.5.7 applicability requirements are adequate to ensure operability of the remote shutdown system controls and instrumentation functions needed to achieve and maintain a safe shutdown condition.
NRC Ouestion No. 2:
The proposed TS Table 3.5-4 only contains source range flux. However, this only covers six decades of counts and its limit is 2-3 decades below the power range. Your application states that the operators are supposed to scram the plant prior to leaving the control room, however, it would take some finite amount of time aller the scram for the power to reduce to the top limit of the source range monitoring. Justify not having Intermediate Range and/or Power Range detectors in the remote shutdown system, i.e., the STS contains a log power neutron flux in addition to the range flux instrument.
Response
As stated in the proposed Technical Specification, the TMI-l Remote Shutdown System is to proside the capability to place and maintain the unit in a safe shutdown condition, defined as Hot Shutdown. Since a stuck rod event is outside the scope of an Appendix R event, the manual plant scram procedurally performed prior to Control Room evacuation is sufficient to ensure that the reactor is at least 1% subcritical while at Hot Shutdown. In reality, due to xenon within the operating reactor core, the actual subcritical margin is greater than 2% for several hours until the xenon decays off Per TMI-l Emergency Procedure 1202-37 it is recognized that it could take 10 or more minutes for the Source Range instmment on the Remote Shutdown Panel to indicate on-scale counts, and the procedure requires at this point that Source Range on-scale indication be verified, and if not indicating on-scale within 15 minutes, to verify shutdown conditions via other means (pressure, temperature, boron). It should also be noted that it would take approximately 8-10 minutes from initiation of the scram to perform all the procedure steps required prior to verifying on-scale Source Range indication.
The critical function of the reactivity monitor in the Remote Shutdown System is to provide indication to ensure that the reactor remains subcritical during cooldown to Cold Shutdown conditions, to ensure that adequate boration is being provided to counteract the positive reactivity added due to decreasing reactor coolant temperature. The TMI-l Source Range instrumentation is sufficient to provide this capability. The adequacy of the TMI-l remote shutdown system was satisfactorily demonstrated in the attemate shutdown capability test described in NRC letter to GPU Nuclear dated October 19,1989.
NRC Ouestion No. 3:
Not all functions listed in Table 7.4-1 of the FSAR are listed in Table 3.5-4 of the proposed TS. How was it decided which functions to include or exclude since all appear to be part of the remote shutdown system.
Note, the Table 3.3.18-1 of the STS is for illustration purposes and not intended to be all inclusive.
Attrchment 1920-99-20438 Page 3 of 3 The above questions are necessary to ensure consistency with the STS for B&W plants as described in NUREG-1430 or in the alternative to adequatelyjustify any differences.
Response
- The items listed in Table 3.5-4 of the proposed TMI-l Technical Specifications are based on Table 3.3.18-1 of the NRC Revised Standard Technical Specification for the Remote Shutdown System, listing those functions applicable to TMI-l which are powered by the protected "B" power train. The proposed Table 3.5-4 listing encompasses the scope of controls and instrumentation functions necessary to achieve and maintain Hot Shutdown, subcritical conditions.. Hot Shutdown is the defined safe shutdown condition for TMi-1.
TMI-l FSAR Table 7.4-1 is much more encompassing, also listing those items powered by the unprotected "A" power train, which are provided for operator convenience and which may not be available in the event of an occurrence which renders the "A" power train out of service. Additionally, the FS AR table lists all the additional functions incorporated as part of the Remote Shutdown System necessary for cooling the plant down to eventual Cold Shutdown mode which are not within the scope of the Standard Technical Specifications.