ML19316A494
| ML19316A494 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/29/1970 |
| From: | Pollard R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Moore V US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7912200748 | |
| Download: ML19316A494 (4) | |
Text
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- June 29, 1970
[T Files THRU:
V. A. Moore, Chief, Electrical Systems Branch, DRS STATUS OF THE OCONEE NUCLEAR STATION POL REVIEW; DOCKET NOS. 50-269,
-270 AND -287 I am presently writing the Electrical Systems Branch portion of the report to the ACRS on the Oconce Nuclear Station.
I believe, however, that the uncertain schedule for review of the Oconee POL applications by the ACRS together with my forthcoming transfer indicates a need to report separately on the status of my review.
Enclosed is a list of all those items which I consider require addi-tional action as of this date. It is expected that most of these items will be resolved by the applicant's responses to outstanding questions. Other items are the result of inadequate responses to questions and additional information is needed to resolve these.
Finally., there are three items which we consider as unresolved and will be reported as such in my report.
t$ t' R. D. Pollard ESB-52 Electrical Systems Branch DRS:ESB:RDP Division of Reactor Standards
Enclosure:
As stated above cc w/ encl:
E. G. Case, DRS R. C. DeYoung, DRL C. G. Long, DRL A. Schwencer, DRL O. D. Parr, DP4 i
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- 12 200plg
June 29, 1970 l
OCONEE POL APPLICATION Ouestions Which Lack Acceptable Ansucrs Question 6.3 requested the applicant to describe the qualification 1.
tests which have been or will be performed on equipment which is The response did not required to be operabic during an accident.
describe the tests and did not discuss whether the tests are planned We need a brief description of the tests and a state-i or completed.
ment that each items has satisfactorily passed the test or a state-ment that the test will be satisfactorily completed prior to the Of particular concern are the sensors which provide ACRS meeting.
reactor trip signals or which actuate the engineered safety feature i
systems.
(e) was not specifically Question 7.3 has been partially answered; part 2.
At this late date in the operating license review, I addressed.
believe that we can complete our report without the information, however; the applicant should be requested to respond to the question.
The response to Question 7.15 states that the rod programmer motors 3.
are powered from a source whose frequency is locked to the plant's Since at least part of the rod control system's a-c power frequency.
power is from inverters, we need to see a summary of a failure mode analysis to show that the frequency variations produced by the inverter are limited to an acceptable value.
2 June 29, 1970 Oconce
-4.
In Question 7.21, we expressed our concerns with the reactor coolant flow sensing scheme. The response addresses the rupture of any common sensing line but this is only one possible failure mode. The concern remains that other single failures (e.g.,
blockage of any one line) may prevent all flow instruments in one loop from responding to flow changes. Uc need to see a summary of a system analysis to cover any single failure.
The fact that 5.
The response to Question 14.3.2 is not adequate.
two channels are provided does not in itself assure that the system meets the requirements of IEEE 279. We need to know whether the system is designed in accordance with IEEE 279 and, in particular, the extent to which the periodic tests of the valves and the closing circuitry duplicates the operation required under accident conditions.
The following questions have not been answered; depending on the 6.
responses, review of the schematics for the systems concerned may be required:
14.3.3 - All or part of the Integrated Control System 14.3.9 - Steam generator water level 14.4.1 - Pressurizer level 14.4.2 - Pressurizer level and heater control j
A question concerning the design of the onsite power distribution 7.
J system was forwarded to DRL with our letter, ESB-26, dated May 15, I understand that this question has been informally transmitted 1970.
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Oconce 3
June 29, 1970 to the applicant and that a formal response will be submitted.
This response should be reviewed by the ESB to determine if the present design is acceptable for the Oconce units.
Unresolved Items 1.
In our letter (ESB-26) to DRL, we discussed two items on which we were unable to reach agreement with the applicant:
(1) Operation with less than four reactor coolant purgs in service, and (2) automatic transfer of power to redundant 600 volt eng't.1.2 red safety feature buses. Based on the ACRS comments on Indian Point Unit 2, we will want to re-evaluate our position regarding the manual set point adjustments proposed by Duke.
Regarding the automatic transfer feature, our report should reflect ourrecom-mended position that it be eliminated.
2.
Dr.11 orris ' letter of February 13, 1970, to the applicant clearly stated our position that all functions required for effective emergency core cooling should be actuated from the sensing of diverse variables. The applicant's position, stated in the response to Question 7.22, is that a diverse reactor trip signal is not necessary because the low pressure trip is reliable. I believe that our position remains the same and that this item l
will be resolved during the ACRS review.
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