ML20138N467

Application for Amend to License NPF-1,consisting of License Change Application 133,revising Tech Spec 3/4.1.3, Movable Control Assemblies, Re Electrical Inoperability of Control Rods

ML20138N467
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	11/01/1985
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20138N458	List: ML20138N455 ML20138N467 ML20138N476
References
TAC-60094, NUDOCS 8511050199
Download: ML20138N467 (4)

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PORTLAND GENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LIGHT COMPANY Operating License NPF-1 Docket 50-344 License Char ge Application 133 This License Change Application requests modifications to Operating License NPF-1 for the Trojan Nuclear Plant to revise Technic.sl Specification 3/4.1.3, " Movable Control Assenblies", with regard to i electrical inoperability of control rods.

l PORTLAND GENERAL ELECTRIC COMPANY By h/ kt (JfEr't D. Withers Vice President N1 clear Subscribed and sworn to before ne this 1st day of November 1985.

Notary Public of 066gon My Commission Expires: M  ! [

v 8511050199 851101 PDR ADOCK 05000344 P PDR

LCA 133 Page 1 of 2 DESCRIPTION OF CHANGE This change revises Trojan Technical Specification (TTS) 3.1.3.1,

" Movable Control Assemblies", as follows:

1. Deletes reference to " full length" rods,

2. Revises the format of the ACTION statements,

3. Adds an ACTION statement for electrical inoperability of the rod control system,

4. Revises ACTION 4 to allow two hours instead of one hour to meet the additional restrictions of this ACTION statement, and

5. Expands the bases associated with TTS 3.1.3.1.

This change is further described below and in revised TTS 3.1.3.1 provided in Attachment 1.

REASON FOR CHANGE TTS 3/4.1.3.1 is revised to delete reference to " full length" rods since all rods are now full length (part length rods were removed in 1983).

The format for the ACTION statements is changed to a tabular format to improve readability. The table lists three causes for inoperability:

(1) mechanical inoperability, (2) misalignment, or (3) electrical inoperability. For each cause of inoperability there is a corresponding ACTION statement for "one rod inoperable" or "more than one rod inoperable".

The major technical change is a new ACTION 3.1.3.1.C regarding electrical inoperability. For the case where one or more rods are electrically inoperable, operation may continue for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to allow for diagnosis and repair. The existing Troj.tt Technical Specifications (TTS) require the Plant to be in HOT STANDBY in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, which is unreasonable when the problem is due to an electrical malfunction. This change'provides dis-

tinct ACTION statements for an inoperable rod consistent with the sig-nificance of the malfunction. A rod that is inoperable due to being untrippable is a more significant failure than a rod that cannot be moved due to an electrical failure, but is still trippable. Therefore, it is prudent to distinguish between these failures and provide a less restrictive ACTION for the less significant failure.

The NRC-approved W-STS (NUREG-0452, Rev. 4) make a similar distinction between electrical and mechanical inoperability, but they do not clearly address the case of more than one rod electrically inoperable, other than by inference, nor do they make allowance for the lesser significance of electrically inoperable rods. This proposed change to the TTS provides

LCA 133 Page 2 of 2 the necessary clarification. A similar change was approved by the NRC for outh Carolina Electric & Gas Company's Summer Plant via Amendment 43 date. June 24, 1985.

ACTION 4 is revised to allow two hours instead of one hour to correct rod misalignment. The one-hour time limit is too restrictive to allow '

diagnosis of the cause of misalignment. This is especially true during backshifts (off-hours) when additional personnel may need to be called to the Plant to perform the diagnosis. The additional hour will allow personnel to perform appropriate tasks in a less hurried manner.

Lastly, the bases to TTS 3.1.3.1 are expanded to provide further interpretation and guidance.

SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION The proposed changes to allow 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, rather than 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, to return an electrically inoperable control rod to service and to allow two hours instead of one hour to correct rod misalignment will not increase the probability or consequences of an accident. The inoperable control rod can still be tripped and, therefore, is available to maintain shutdown margin.

The proposed change does not create the possibility of a new or different

kind of accident nor reduce a margin of safety. This change provides personnel with sufficient time to perform orderly diagnosis and repair.

By precluding a hurried diagnosis, the potential for human error is mini-mized. In addition, requiring a plant shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> due to a rod control system failure per the existing TTS subjects plant systems to unnecessary challenges that would not occur if the plant remained at stable POWER OPERATION, Therefore, in this situation, continued plant operation is inherently safer than a forced shutdown.

This change does not affect the power distribution limits in TTS 3/4.2 since these limits remain unchanged. Notwithstanding TTS 3.1.3.1, power distribution perturbations induced by an inoperable or misaligned control rod will continue to be limited by satisfying the requirements of the appropriate power distribution TTS.

The deletion of the words " full length" and reformatting of the ACTION statements are administrative changes and, therefore, do not pose a significant hazard.

SAFETY / ENVIRONMENTAL EVALUATION Safety and environmental evaluations were performed as required by 10 CFR 50 and the Trojan Technical Specifications. This review determined that the proposed changes do not create an unreviewed safety question.

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