ML20125D934

Submits Current Status of Work on Tech Spec Limiting Condition for Operation 4.1.9 Re Core Region Temp Rise. Calculational Differences Between Thermal/Hydraulic Analyses Being Investigated.Summary of Open Items Provided

ML20125D934
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/20/1985
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
P-85159, TAC-52634, NUDOCS 8506120520
Download: ML20125D934 (2)

Text

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c PublicService Company of Colorado 2420 W. 26th Avenue, Suite 1000, Denver, Colorado 80211 May 20, 1985 Fort St. Vrain Unit No. 1 P-85159 m3M DWMN Regional Administrator Region IV U.S. Nuclear Regulatory Commission MAY 311985 I

611 Ryan Plaza Drive, Suite #1000

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Arlington, Texas 76011

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Attn: Mr. Eric Johnson Docket No.

50-267

SUBJECT:

Additional Information on Proposed Amendment to LC0 4.

1.9 REFERENCES

(1) PSC letter, H. L. Brey to E. H. Johnson, dated November 20, 1984 (P-84504)

(2) PSC letter, H. L. Brey to E. H. Johnson, dated February 8, 1985 (P-85013)

Dear Mr. Johnson:

This letter is to report the current status of work on Fort St. Vrain Technical Specification LCO 4.1.9, Core Region Temperature Rise.

Calculational differences between thermal / hydraulic analyses done by Oak Ridge National Laboratories (ORNL Mr.

S.

Ball) and GA Technologies (GA Mr. R. Kapernick) are being investigated. ORNL and GA have agreed upon benchmark cases to be analyzed as a means of resolving the differences. GA benchmark analyses have been sent to ORNL. With the NRC Project Manager's concurrence, Messrs.

Ball and Kapernick have been encouraged to discuss their benchmark analyses directly with each other to expedite the resolution of the calculational differences.

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2-t An investigation of the auxiliary steam supply relative to circulator

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motive force requirements has been completed. The results show that i

the existing auxiliary steam supply is theoretically adequate to provide the motive force for the circulators which would be required by the various flow requirements under consideration in addition to l

other normal steam demands.

L Preliminary calculations on the adaptation of the P0KE Code to predict optimum orifice positions have been completed.

The results indicate feasibility of this approach.

A summary of the open items'at this time is as follows:

Resolve the calculational differences between ORNL and GA l

analyses.

l Resolve the uncertainties associated with flow indications at l

low flow rates relative to LC0 4.1.9 flow requirements.

Confirm the capability of the POKE Code to predict optimum orifice positions at power.

t Submit a revised LC0 4.1.9 Amendment based on resolution of the above and which addresses the situation of a limited l

number of mispositioned orifice valves.

l PSC will submit further information on the status of the resolution l

of these open items by August 1, 1985.

If you have any questions, please contact Mr. M. H. Holmes at (303) 571-8409.

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Very truly yours,

%M%u-H. L. Brey, Manager Nuclear Licensing and Fuels Division i

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