ML20129D164

Advises That Activities on Mods to Low Temp Overpressure Protection Sys Planned for 1985 Refueling Outage Suspended Until Draft Reg Guide 1.99 Published.Revs to Tech Specs Will Be Proposed to Incorporate Methodology in Reg Guide 1.99

ML20129D164
Person / Time
Site:	Yankee Rowe
Issue date:	07/10/1985
From:	Papanic G YANKEE ATOMIC ELECTRIC CO.
To:	Zwolinski J Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.099, RTR-REGGD-1.099 FYR-85-76, NUDOCS 8507160442
Download: ML20129D164 (2)

Text

r q Te'ephone (6 ") 8' -a 'oo YANKEE ATOMIC ELECTRIC COMPANY TWX 710-380-7619 g< g ,,7,

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1671 Worcester Road Framingham, Massachusetts 01701 2.C.2.1 FYR 85-76 f {

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July 10, 1985 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Mr. John A. Zwolinski, Chief Operating Reactors Branch No. 5 Division of Licensing

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) YAEC Letter to USNRC, dated April 23, 1984 (FYR 84-51)

(c) USNRC Letter to YAEC, dated December 3, 1984 (d) YAEC Letter to USNRC, dated December 1, 1976 (WYR 76-125)

Subject:

Low Temperature Overpressure Protection (LTOP)

Dear Sir:

In Reference (b), we indicated our plans to modify the LTOP System to provide intermediate sotpoint adjustments to more suitably cover the range of temperatures and pressures through all operating modes. We also indicated that the progress of the revision to Regulatory Guide 1.99 would be closely monitored for its potential impact on our proposed system modifications.

Recent drafts of Regulatory Guide 1.99 have been reviewed; and the results show that substantial benefits will be gained in its use for adjusting the Appendix G curve, eliminating the need to make system modifications.

Therefore, we have suspended activities on the modifications which were planned for the 1985 refueling outage until the draft Regulatory Guide is finalized and published (expected in early 1986). At that time, revisions 6.o the Technical Specifications will be propo ted to incorporate the methodology described in Regulatory Guide 1.99.

In the interim, the foll'owing actions will be continued in order to maintain the similar levels of protection as demonstrated in the original design basis:

1. The setpoint of the PORV shall be maintained in the low setpoint position until the Main Coolant System temperature is greater than or equal to 3800F.

2. Maintain a 400 psig margin between plant condition and the existing Appendix "G" curve above 3000F.

8507160442 850710 i PDR ADOCK 05000029 P PDn goo) i D i

United States Nuclect Regulatory Commission July 10, 1985 Attention: Mr. John A. Zwolinski Page 2

3. Station a dedicated operator at the control board during operations in which the Main Coolant System temperature is between 3000F and 4500F whose sole responsibility is to monitor Main Coolant System pressure, and the status of pressurizer heaters and bleed flow, the status of the safety injection pumps and valve lineup for added assurance to prevent / mitigate potential LTOP events.

It should be noted that Action 2 has been changed from that previously stated in Reference (b). The "above 3000F" has been added to allow starting the plant from a cold shutdown condition. This temperature limit has already been in use at the plant and is incorporated into the plant operating procedure. In addition, the pressure margin requirement has been reduced from 500 to 400 psig to maintain adequate margin to main coolant pump NPSH limits.

The original requirement, in Reference (d), was established based on operator response time for inadvertent pressurizer heater operation prior to stationing a dedicated operator. This minor change in response time requirement is adequately compensated by the use of a dedicated operator. The upper limit

-temperature for stationing the operator in Action 3 has been increased from 440 0 F to 4500F, reflecting the shift in the Appendix G curvt..

If this is not satisfactory or you have any questions, please contact us.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY G. Pap, Jr.

Senior Project Engineer - Licensing GP/dps

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