ML19259D209
| ML19259D209 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/12/1979 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Rubenstein L Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910170367 | |
| Download: ML19259D209 (2) | |
Text
TEB'NESSEE VALLEY AUTHCRITY CH ATTANCCGA TENN ESSEE 371o1 400 Chestnut Street Tower II October 12, 1979 Director of Nuclear Reactor Regulation Attention:
Mr. L. S. Rubenstein, Acting Chief Light Water Reactors Branch No. 4 Division of Project Management U.S. Nuclear Regulatory Coc: mission Washington, DC 20555
Dear Mr. Rubenstein:
In the Matter of the Application of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 Enclosed is a revised response to the Reactor Systems Branch (RSB) question on boron dilution transmitted by your letter to H. G. Parris dated August 7, 1979. This revision was requested by the RSB Reviewer, F. Orr, in a telephone conversation on September 24, 1979.
Very truly yours, TENNESSEE VALLEY AUTHORITY
'\\. & U L. M. Mills, Manager Nuclear Regulation and Safety Enclosure
).
\\
p 7910170 4
JR.,.
W ENCLOSURE REVISED RESPONSE TO 1TCM OF L. S. RUBENSTEIN'S LETTER TO H. G. PARRI'2 UATED AUGUST 8, 1979 Item 1 Reactor System Branch - (212.0) 15.16B Confirm the pointa discussed in the telephone call of July 24, 1979, with respect to operator actions related to the detection of a boron dilution event at the time of reactor shutdown.
The points discussed which require confirmation are the following:
(a) Within what time interval after shutdown will the operator make his first check of the setting of the High Flux at Shutdown alarm?
(b) Within what margin fr~m background level will the operator maintain this High Flux at Shutdown alarm based on his first check and at each subsequent check?
Response
In accordance with Sequoyah Nuclear Plant Units 1 and 2 Surveillance a.
Instruction-603 - (High Flux Adjustment After Shutdown) - The high flux at shutdown alara setting will be adjusted to no higher than 1/2 decade above the count rate 30 minutes after plant shutdown.
b.
As shown in Surveillance Instruction 603, the alarm setpoint must be set or verified every 30 minutes for the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following plant trip, every 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and once per shift thereafter until the flux level has stabilized.
s