ML20054H987
| ML20054H987 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/18/1982 |
| From: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-01, TASK-05-11.A, TASK-07-01.A, TASK-07-03, TASK-3-1, TASK-5-11.A, TASK-7-1.A, TASK-7-3, TASK-RR FYR-82-62, NUDOCS 8206250291 | |
| Download: ML20054H987 (3) | |
Text
YANKEE ATOMIC ELECTRIC COMPANY
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June 18, 1982 FYR 82-62 2.C.2.1 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
References:
(a) License No. DPR-3 (Docket No. 50-29)
(b) USNRC Letter to YAEC dated February 2,1982 (c) USNRC Letter to YAEC, dated February 1, 1982 (d) USNRC Letter to YAEC, dated February 22, 1982
Subject:
Additional Information on SEP Topics V-11.A, VII-3, III-1 (Electrical), and VII-1.A
Dear Sir:
The attached information documents our review of the subject SEP topics and provides clarifications and revisions to the staff evaluations contained in References (b), (c), and (d).
If you have any questions, please contact us.
Very truly yours, A
E ATOMIC ELECTRIC COMPANY
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M A. Kay Senior Enginee - Licensing JAK: dad Attachment b
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8206250291 820618 PDR ADOCK 05000029 P
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YANKEE ATOMIC o
SEP TOPIC V-11.A - REQUIREMENTS FOR ISOLATION OF HICH AND LOW PRESSURE SYSTEMS The NRC topic assessment was reviewed for accuracy, and only one discrepancy was noted. The air operated valve in the CVCS system letdown Ifne, LCV-222, closes automatically on low pressurizer level, not on low pressurizer pressure as their report states. However, this discrepancy should not affect the evaluation.
SEP TOPIC VII-3 AND III-I - SAFE SHUTDOWN SYSTEMS (ELECTRICAL)
The following information corrects several inaccuracies in the EC&G Report No. 06085 and provides clarifications on the conclusions contained therein.
1.
The Transformer A and B Busses are safety-related, and are, therefore, considered to be Class lE power supplies.
2.
Each loop has a safety injection pressure channel in addition to the loop pressure channels which senses the same point, and are powered from the Transformer B Bus.
3.
All control rod position indicators are powered from the Transformer A Bus.
4.
One source range nuclear detector channel which is used specifically for refueling is powered from the Transformer A Bus.
5.
One high range area radiation monitor is powered from the Vital Bus.
4 The NRC assessment had two conclusions or requirements. One requirement calls for an additional set of instruments powered from an independent Class IE power source for the following parameters:
1.
Pressurizer level (wide range),
2.
Pressurizer pressure, 3.
Reactor inlet temperature, 4.
Reactor outlet temperature, 5.
Nuclear power, 6.
Charging flow, 7.
Corponent cooling water (CCW), and 8.
Service water system flow.
The Transformer A and B Busses are independent Class IE power supplies.
Based on this, redundantly powered instruments already exist for pressurizer level, pressurizer pressure, and nuclear power. As for the other parameters listed above:
1.
All main coolant temperature instruments are powered from the Vital Eus at the present time.
During the 1982 refueling outage, a new Vital Bus will be installed, and it has already been recommended to split the main coolant temperature instrument power supplies between the new and existing vital busses.
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i 2.
Only one channsi of charging flow exists and it is powared from the Transformer A Bus.
Redundant channels of flow indication should not be necessary since pressurizer level indication, which is redundant, is the primary indication of concern. Charging flow rate does not matter if pressurizer level is being maintained.
3.
Only one channel of CCW surge tank level exists, and it is pneumatic.
CCW system operation is only required to support shutdown cooling system operation for cold shutdown. Also, a high and low level alarm is available in the Control Room to offer some redundancy. Redundant surge tank level indication is not necessary considering the availability of tank level alarms, and the use of this system for cold shutdown only.
4.
No channels of service water system flow presently exist. CCW temperature indication on the cutlet of the CCW heat exchangers is adequate to monitor for service water flow. In addition, CCW temperature is indicated and alarmed at the inlet to the CCW heat exchanges. Also, this system is required during CCW and shutdown cooling systems operation (i.e., cold shutdown only).
Based on the discussion above, the only area that does not comply to the redundant power supply requirements is the main coolant temperature instruments. This requirements should be satisfied with the new vital bus modifications planned for the next refueling outage.
The other requirement calls for an additional power supply for the shutdown cooling system isolation valves, SC-MOV-551, 552, 553, and 554.
These four valves are presently powered from the same breaker on MCC 1, Bus 1.
The purpose of the additional power supply is to prevent a single failure from disabling the Shutdown Cooling System.
This concern is based on the requirements of BTP RSB 5-1.
However, the branch technical position allows older plants an exemption from this requirements if a return to hot standby is possible until manual actions can be taken to open the valves. This exemption is discussed in Section 5.2.1.1 of EG6G report 0608J. Our present configuration is acceptable based on this exemption.
SEP TOPIC VII-1.A - ISOLATION OF REACTOR PROTECTION SYSTEM EC&G's report is fairly complete and accurate.
They have incorporated most of our earlier comments on their first report. In two cases analog indicators, which are an integral part of the signal loop, have not been included in their descriptions. These are the Main Coolant Pressure channels discussed on Page 5 and the Low Steam Generator Water level discussed on Page 6.
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