ML20099H793

Submits Addl Info Requested by NRC During 840823 Meeting Re Proposed Amend to Limiting Condition for Operation 4.1.9 Concerning Automated Orifice Valve Adjustments.Work Continuing on Listed Remaining Issues

ML20099H793
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/20/1984
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
P-84504, TAC-52634, NUDOCS 8411280311
Download: ML20099H793 (3)

Text

p public Service Company Cf OcBomHe P.O. BOX 840 DENVER, COLORADO 80201 November 20, 1984 Fort St. Vrain Unit No. 1 P-84504 Regional Administrator Region IV ggggy@ k U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite #1000 NOV231984 Arlington, Texas 76011 g ATTN: Mr. Eric H. Johnson DOCKET NO. 50-267

SUBJECT:

Additional Information on Proposed Amendment to l

LC0 4.1.9 1

REFERENCE:

NRC Memorandum, Wagner to Ireland, Dated September 6, 1984 (G-84345)

Dear Mr. Johnson:

This letter addresses the additicnal information requested by the NRC l

during a meeting on August 23, 1984 regarding the proposed amendment to LC0 4.1.9.

PSC has evaluated automating orifice valve adjustments as a potential l

means of reducing the transition time between equal flow and equal outlet temperature orifice patterns. We have considered the suggestions made during the meeting. However, due to the complexity of the adjustment process and the potential complications and accident possibilities associated with operatirg orifice valves without direct operator control, it has been concluded that the most practical and advantageous modification would be to simply provide the operator with the capability to reposition each valve faster than l4 0 0 T h ,

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O the existing indexer permits. Responsibility for developing a suitable modification to permit faster orifice valve repositioning has been assigned to the Nuclear Engineering Division.

LC0 4.2.1 and LC0 4.2.2 are being revised to ensure that the capability to resume core helium flow within a predetermined period of time based on core afterheat using at least one helium circulator will be maintained. The predetermined period -of time shall be limited such that fuel damage will tiot occur. The revised Technical Specification will include requirements for power, low power and shutdown conditions which will define the minimum levels of circulator operability for each case. The proposed Technical Specification Amendment is expected- to be submitted to the NRC by December 31, 1984.

We have also reevaluated the existing LCOs 4.1.3, 4.1.7, and 4.1.9 with consideration to integrating the . requirements into a single limitation. Our conclusion is tha+ the LCOs are not amenable to being integre.ed. The fundamental difticulty is that they deal with diverse and independent parameters. LC0 4.1.3 - Rod Sequence deals with control rod reactivity worth, while LC0 4.1.7 -

Inlet Orifice Valves deals with region outlet coolant temperature variances, and LCO 4.1.9 - Core Region Temperature Rise deals with coolant flow.

Integration of these LCOs would necessitate a technical specification significantly more complex, more confusing, and more difficult to implement than the current ones. Therefore, we have decided not to attempt to integrate them.

Work is continuing on the following remaining issues:

Sources of core flow and core power level indications available to the operator.

The impact of a limited number of mispositioned orifice valves on the transition between equal flow valve positions and equal outlet temperature valve positions.

• Correcting the nonconservatism in the calculation of the pressure drop through the orifice valve discovered in July 1 1984.

Evaluating various sources of motive power to enhance circulator helium flow capabilities.

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Additional information on these issues will~ be submitted by January 15, 1984. If you have any questions in the meantime, please contact Mr. M. H. Holmes at (303) 571-8409.

Very truly yours,

)

]-tWW H. L. Brey Executive Staff Assistant Electric Production HLB /JL/kt L'