ML19270G990

Clarifies Main Steam Temp Limits Originally Specified in Ltr Ref P-79094.Results of Fluctuation Tests at Each Power Level Will Be Forwarded Upon Completion

ML19270G990
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/15/1979
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Kuzmycz G Office of Nuclear Reactor Regulation
References
P-79131, NUDOCS 7906220308
Download: ML19270G990 (5)

Text

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public service company oe cenowc P. O. Box 361, Platteville, CO 80651 June 15, 1979 Fort St. Vrain Unit No. 1 P-79131 Mr. George Kuzmycz, Project Manager U. S. Nuclear Regulatory Cor: mission Division Prcject Management Special Projects Washington, D.C. 20535

Subject:

Startup Test Plans Ref: P-79094

Dear Mr. Kuzmycz:

Per our recent telephone conversation the following is submitted as clarification to main steam te=perature limits originally specified in the above referenced letter as Item 2 under " Corrective Action".

Item 2 under Corrective Action on page 4 of F-79094 should be re-vised to read as follows:

2. If any of the following conditions are exceeded i= mediate action will be taken to terminate the fluctuation test and further test-ing in fluctuation mode will be suspended until authorization to proceed is obtained from the Cot: mission.

a) Technical Specification limits are exceeded b) An increase in primary coolant activity levels greater than a factor of five (5) over prior equilibrium values for that power level c) A temperature change of module main steam temperature of 150*F relative to the initial steady state temperature and exclusive of te=perature change due to load changes d) A module main steam temperature which exceeds 1075*F.

The basis of selecting the main steam temperature limits of a 150*F change or 1075* maximum temperature, are as follows:

1. The -150*F temperature variation was selected based on previous analysis that 120 scram cycles of 330*F drop in main steam temp-erature were acceptable per the steam generator module fatique p nP 2348 106 7' I 7906220 308

Mr. George Kuzmycz Page 2 June 15, 1979 design life analysis. Unidirectional decreases of 130*F were observed during Cycle I fluctuation tests.

2. The +150*F change or 1075* maximum, whichever is less, is based on two conditions. At lower power levels, the fluctuation test is conducted at a main steam temperature of 910*, and a unilateral temperature change of +150*F would result in a maximum main steam temperature of 1060*F. At higher power levels the test is con-ducted with a main steam temperature of 980*-995*F and a unilateral temperature increase of 150*F would not be permitted.

The maximum temperature of 1075"F was selected on the basis of the stress report for steam generators, CADR-9, which shows that main steam temperatures up to 1090*F are acceptable on a short term basis. The maximum main steam temperature experienced during Cycle I fluctuation tests was 1036*F.

Based on the above information the limits established in the revised para-graph 2 are conservative relative to the capabilities of steam generators.

It should be noted that these limits are established only for the purpose of test suscension for Commission review and approval prior to performing additional luctuation tests. Test limits for taking corrective action to terminate fluctuations are obviously much lower.

Also, per our telephone conversations, we will provide the Commission with a brief summary of each fluctuation test at each power level as soon as possible after completion of each test. This test summary will include information that is readily available from our plant instrumentation system.

Obviously any of the more sophisticated data such as gap temperatures, dis-placement probes, ICRD data and FM data vill require some time to reduce and analyze and therefore cannot be provided to you on a continuous basis.

A sample of a proposed su= mary report is attached.

If you have any question or comments please contact me. We would appreciate your concurrence with resumption of fluctuation testing, based on the limits set forth at your earliest convenience.

Very truly yours, h ? hun /%

Don W. Warembourg /

Manager, Nuclear Production DWW:pc Attachment 2348 107

FORT ST. VRAIN UNIT NO. 1 Fluctuation Test Summary RT-500 Prepared By: Date:

Test No. Date: Time:

Plant Conditions Beginning of Test Reactor Power  :

Core Resistance Core AP psi Helium Flow  %

Avg. Core Outlet Temp. *F Avg. Core Inlet Te=p. *F Avg. Main Steam Temp. *F Primary Coolant Activity cpm Fluctuation Conditions Method of inducing fluctuation Reactor Power Level  %

Largest Fluctuation A=plitude on Nuclear Channels (Peak to Peak)

Channel I  %

Channel II  %

Channel III  %

Channel IV %4h j]g Channel V  % Channel VI  % Core Outlet Temperature (Identify Specific Regions) Preselected Regions en Trend Recorders Region *F to *F Region *F to *F

Steam Generator Modules Largest Change, ibdule Mhximum Main Steam Main Steam Temo Temp Observed B-1-1 *F to *F B-1-2 *F to *F B-1-3 *F to *F B-1-4 *F to *F B-1-5 *F to *F 3-1-6 *F to *F B-2-1 *F to *F B-2-2 *F to *F B-2-3 'F to *F B-2-4 *F to *F B-2-5 *F to *F B-2-6 *F to *F Time Fluctuation Started Time Fluctuation Terminated Method of fluctuation termination Plant Conditions When Fluctuation Terminated Reactor Fower  % Core Resistance Core AP psi Avg. Core Outict Temp. *F ig Avg. Core Inlet Temp. 'F Primary Coolant Activity cpm

Remarks: (Provide a general description of the fluctuation including ave-race periods, apoarent areas of core involvement and any test limits that may have been exceeded.) 2348 110}}