B11724, Application for Amend to License DPR-21,modifying Wording of Tech Specs 3.10 & 4.1.D,Table 3.1.1 & Basis 3.1 to Allow Flexibility in Disarming Control Rods by Allowing Variety of Disarming Methods

Application for Amend to License DPR-21,modifying Wording of Tech Specs 3.10 & 4.1.D,Table 3.1.1 & Basis 3.1 to Allow Flexibility in Disarming Control Rods by Allowing Variety of Disarming Methods

ML20198B602
Person / Time
Site:	Millstone
Issue date:	10/30/1985
From:	Opeka J, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Zwolinski J Office of Nuclear Reactor Regulation
Shared Package
ML20198B606	List: B11724, Application for Amend to License DPR-21,modifying Wording of Tech Specs 3.10 & 4.1.D,Table 3.1.1 & Basis 3.1 to Allow Flexibility in Disarming Control Rods by Allowing Variety of Disarming Methods ML20198B609
References
B11724, NUDOCS 8511070093
Download: ML20198B602 (3)

Text

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.am wi.e cwa' H ARTFORD. CONNECTICUT 06141-0270 k L J ((,[,$2,[*[ (203) 66s-5000 October 30,1985 Docket No. 50-245 Bil724 Director of Nuclear Reactor Regulation Attn: Mr. John A. Zwolinski, Chief Operating Reactors Branch #5 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:

Millstone Nuclear Power Station Unit No.1 Proposed Revision to Technical Specifications Disarmed Control Rods Pursuant to 10 CFR 50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License DPR-21, by incorporating the attached proposed changes into the Millstone Unit No.1 Technical Specifications.

The proposed changes are provided as Attachment 1. The purpose of these proposed changes is to modify the wording in the Technical Specifications with respect to disarming control rods when the Refuel Interlocks or Reactor Protection System (RPS) Trip Functions are inoperable. The v ording is being changed to be consistent with the wording in Standard Technical Specifications (STS) where control rods are required to be inserted and either electrically o_r hydraulically disarmed rather than both electrically and hydraulically disarmed.

The proposed wording change to Technical Specifications 3.10, 4.1.D, Table 3.1.1 and Bases 3.1 would allow flexibility in disarming control rods by allowing a variety of disarming methods (any one of which is sufficient to ensure that the control rods remain fully inserted). The particular disarming method to be used could then be determined at the required time based on the then-current plant configuration. Disarming methods include:

o Hydraulically disarming each control rod by closing its respective insert and withdraw line valves at the hydraulic control unit (HCU). This method hydraulically locks the control rod in place even if a movement command is given.

o Electrically disarming each control rod by pulling the Amphenol connectors (solenoids) from the Reactor Manual Control System (RMCS) at the HCU. '

This method prevents any movement command from the RMCS reaching that particular control rod. - 00

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r o Electrically disarming the RMCS by pulling the Rod Drive-in Bus and Rod Drive-out and Settle Bus fuses in the RMCS. This orevents any movement command from being generated in the RMCS and sent to the individual control rods. This method electrically disarms all control rods at once.

Any one of the above methods is sufficient to ensure that the control rods will remain fully inserted during the times when RPS Trip Functions or Refuel Interlocks are inoperable.

NNECO has reviewed the attached proposed change pursuant to 10 CFR 50.59 and has determined that it does not constitute an unreviewed safety question.

Specifically, the margins of safety as defined in the Technical Specification Bases are maintained. In addition, the probability of occurrence or the consequences of a previously analyzed accident have not been increased and the possibility for a new type of accident not previously evaluated has not been created. The proposed change would allow either hyoraulically or electrically disarming the control rods. Requiring either, but not both, is potentially beneficial in that it will decrease the probability of an error and improve the availability of equipment or improve system performance as described in more detail below.

NNECO has reviewed the proposed change, in accordance with 10 CCQ 50.92, and has concluded that it does not involve a significant hazards consideration.

The basis for this conclusion is that the criteria of 10 CFR 50.92(c) are not compromised, a conclusion which is supported by our determinations made pursuant to 10 CFR 50.59. Additionally, the Commission has provided guidance concerning the application of the standards in 10 CFR 50.92 by providing certain examples (48 FR 14870, April 16,1983). The proposed change is most closely enveloped by example (vi) of actions not likely to involve a significant hazards consideration. The proposed change involves a modest relaxation in the operability requirement of the existing Technical Specifications, but is within acceptable criteria as defined in Standard Technical Specifications, the applicable document analogous to the Standard Review Plan discussed in example (vi). The proposed change will decrease the probability of an error and improve the availability of equipment or improve the system performance for the following reasons:

o By not requiring that the control rods be always hydraulically disarmed, manual cycling of 290 insert and withdraw valves can be precluded. Thus a valving errce could be prevented which, while not a safety concern (the affected rt4(s) would remain fully inserted), could cause delays in start-up and lost time due to trouble-shooting the system to find the problem. This chance of error can be avoided if the plant configuration is such that electrical dis trming is feasible.

o Not always requiring hydraulic disarming also allows the use of control rod drive pumps as a make-up source of water to the reactor. This source is not available if all rods are hydraulically c'isarmed and the return line is not available due to maintenance on feedwater lines or check valves.

By not requiring both the hydraulic and electrical disarming method the probability of an error is decreased and the availability of equipment and system performance is improved. It is noted that this proposal is consistent with the current version of Standard Technical Specifications.

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The Millstone Unit No.1 Nuclear Review Board has reviewed and approved the attached proposed revision and has concurred with the above determinations.

In accordance wi.th 10 CFR 50.91(b), NNECO is providing the State of Connecticut with copy of this proposed amendment.

Pursuant to the requirements of 10 CFR 170.12(c), enclosed with this amendment request is the application fee of $150.00.

We trust you find this information satisfactory.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

)i .b u f

3. F. Opeka '

Senior Vice President By: C. F. Sears Vice President cc: Mr. Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, Connecticut 06116 STATE OF CONNECTICUT )

) ss. Berlin COUNTY OF HARTFORD )

Then personally appeared before me C. F. Sears, who being duly sworn, did state that he is Vice President of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.

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