ML20214J142
| ML20214J142 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/21/1986 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.K.3.05, TASK-TM GL-86-06, GL-86-6, NUDOCS 8612010172 | |
| Download: ML20214J142 (4) | |
Text
6 s
BALTIMORE GAS AND ELECTRIC CHARLES CENTER P. O. BOX 1475 SALTIMORE, MARYLAND 21203 JOSEPH A.TIERNAN WcE PnEsIDENT NucLEAn ENEnOY November 21,1986 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 ATTENTION:
Mr. Ashok C. Thadani, Director PWR Project Directorate #8 Division of PWR Licensing-B l
SUBJECT:
Calvert Cliffs Nuclear Power Plant l
Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Response to Generic Letter 86-06, " Implementation of TMI Action item II.K.3.5, Automatic Trip of Reactor Coolant Pumps"
REFERENCES:
(a)
Generic Letter 86-06, Implementation of TMI Action item II.K.3.5,
" Automatic Trip of Reactor Coolant Pumps," dated May 29,1986 (b)
Letter from Mr. 3. A. Tiernan (BG&E), to Mr. A. C. Thadani (NRC),
dated October 23,1986, same subject (c)
Combustion Engineering Report CEN-268, " Justification of Trip Two/ Leave Two Reactor Coolant Pump Trip Strategy During Transients," March 1984 Gentlemen:
Reference (a) requested additional plant specific information regarding our trip two/ leave two procedures for small break Loss of Coolant Accidents. We provided this information in Reference (b) with the exception of our Subcooled Margin Monitor's (SMM) loop uncertainties. The SMM's loop uncertainties are provided as an attachment to this letter.
Should you have any questions regarding tnis matter, we will be pleased to discuss them with you.
Very truly yours, hk h
(te JAT/LSL/ dim Attachment
i Mr. Ashok C. Thadani November 21,1986 Page 2 cc:
D. A. Brune, Esquire
- 3. E. Silberg, Esquire S. A. McNeil, NRC T. Foley, NRC
e g
ATTACHMENT RESPONSE TO GENERIC LETTER 86-06 The following provides oar Subcooled Margin Monitor's (SMM) instrument loop uncertainties in response to plant specific questions addressed in Generic Letter 86-06:
QUESTION:
Identify the instrumentation uncertainties for both normal and cdverse containment conditions. Describe the basis for the selection of the adverse containment parameters. Address, as appropriate, local conditions such as fluid Jets or pipe whip which might influence the instrumentation reliability.
RESPONSE
The basis for selection of the adverse containment parameters was the Updated Final Safety Analysis Report, Tables 14.20-1,12,13, and 15. Primary coolant activity was assumed to be at Technical Specification limits. The effects from fluid jets and pipe whip were not considered due to the redundancy associated with each of the safety-related instruments which provide an input to the SMM.
The SMM's instrument loop uncertainty is a function of the temperature of the primary due to the inherent relationship between temperature and pressure at saturated conditions.
The SMM's loop uncertainties for normal and adverse containment condigons are 17 F and 26 F, respectively, during the first ten minutes of a 0.1 ft small break Loss of Coolant Accident (SBLOCA) as shown in Reference (c). These uncertainties bound the uncertainties of the SMM during a Steam Generator Tube Rupture (SGTR).
QUESTION:
In addressing the selection of the criterion, consideration of uncertainties associated with the CEOG supplied analyses values must be provided. These uncertainties include both uncertainties in the computer program results and uncertainties resulting from plant specific features not representative of the CEOG generic data group.
RESPONSE
Our trip two/ leave two subcooling setpoint (30 F) combined with the SMM's loop uncertainties is conservative when compared to the nominal setpoint (O F) of Reference (c) for both a SBLOCA and a SGTR.
I
o-ATTACHMENT RESPONSE TO GENERIC LETTER 86-06 We are presently reviewing the use of the high range containment radiation monitor with our trip two/ leave two strategy. Should we decide to replace this monitor with an alternative indication, we will use.the steam generator blowdown recovery radiation monitor and the condenser air removal discharge monitor. These are consistent with the steam plant radiation alarm recommended in Reference (c) as an alternative indication. _ _._
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