ML19211C610
| ML19211C610 | |
| Person / Time | |
|---|---|
| Issue date: | 11/07/1979 |
| From: | Kniel K Office of Nuclear Reactor Regulation |
| To: | Moore N NRC OFFICE OF INTERNATIONAL PROGRAMS (OIP) |
| Shared Package | |
| ML19211C606 | List: |
| References | |
| FOIA-80-336 SECY-79-674, NUDOCS 8001140050 | |
| Download: ML19211C610 (2) | |
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MEMORANDUM FOR: Neal ifoore, Actina Assistant Director for..
Exports and Imports and International SafequMid@0IP UIE5.:U.Y'i.'37ap" FROM:
Karl Kniel, Chief, Core. Performance Branch', DSS
SUBJECT:
RESPONSE TO OUESTIONS RAISED IN THE MEMORANDUM TO KARL KNIEL FROM NEAL MOORE, DATED NOVEMBER 1,1979 The following responses are provided to the ouestions raised in the subject memorandum.
Question 1.
What functions do the detectors perform in reactor operations and how essential to the safe operation of the reactors are they? What are the consequences of continuing to operate the Tarapur Units with defective probes, The TIP (Traversing Incore Probe) systen is used to calibrate the LPRMs
( Local Power Range Monitorsh In particular a single TIP is run throuah a laroe number of LPRMs in order to assure that their relative readinos are known. The LDRMs are combined in particular ways to form the Average Dower Panoe Monitor (APRM) System which is used as a reactor power input to the reactor protection system. The reactor protection system will not assure that the reactor is shutdown in response to. severe transients or accidents if the reactor power input is incorrect.
In addition the LPRM outputs are used by the plant computer to obtain the core nower distribution during ooeration.
From the core cower distribution the core coeratina parameters, such as minimum critical power ratio (MCPR), maximum linear heat generation rate (MLHGR) and the maxinum average planar heat ceneration rate (MAPLHGR), are determined.
Decalibration of only a few of the LPRMs could lead to operation of the reactor in a nanner such that the initial conditions assumed for anticinated transients and accidents are violated.
Question 2.
Do technical specifications or operating procedures normally dictate how many orobes should be maintained as spares for a BPR of the Taracur Type, or, it not, what would be your judcement for maintaining a stock of soares.
Technical Specifications do not specify any number of probes to be kept as spares. Ne are not aware of the requirements of the Taracar operatina orocedures. However, the Technical Specifications for boiling water
Contact:
W. Brooks, x27577 1743 353 80 0u 4o os o
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NOV 7 7979 reactors licensed by NRC require the calibration of the LPRMs once each effective full power month.
In the ever.t that a TIP is not operable this calibration cannot be performed and, unless relief from the Technical Specification requirements is obtained from the NRC operation cannot continue. Simple prudence, therefore, dictates that spares be kept.
The number would depend on the failure rate of TIPS and the lead time for obtaining replacements.
Question 3.
How would the continued operation of a domest'ic reactor be affected, assuming the existence of conditions similar to those that now exist at Tarapur?
See the answer to Question 2.
Question 4.
In your judgement would the export of any or all of the probes be required before March 10, 1980?
If the question is interpreted to mean will Tarapur need any of the probes by March,1980 the answer is yes, according to the General Electric letter of October 1,1979.
It is our judgement that it is prudent on the part of Tarapur to have at least one soare for each probe, and thus the request for six probes is reasonable.
Karl Kniel, Chief' Core Perfomance Branch Division of Systems Safety cc:
W. Brooks D. Fieno 1743 354
.