ML19350E299
| ML19350E299 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 06/15/1981 |
| From: | Colbert W DETROIT EDISON CO. |
| To: | Kintner L Office of Nuclear Reactor Regulation |
| References | |
| EF2-53694, NUDOCS 8106170278 | |
| Download: ML19350E299 (5) | |
Text
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s MI + n imm;t;mm w w.vvi i ooi m m June 15, 1981 EF2 - 53694 Mr. L. L. Kintner Division of Project Management Office of Nuclear Peactor Regulation U. S, Nuclear Begulatory Cannission Washington, D. C.
20555
Dear Mr. Kintner:
Beference: Enrico Fermi. Atonic Ibwer Plant, Unit 2 NBC Docket No. 50-341
Subject:
Questions on Apcendix H, Isolation Dependability Attached a.re responses to concerns expressed, by John Lane (NBC) to Lerry Schuerman (Edison) on FSAR Appendix H, Table H.II.E.4.2-1.
Begarding the tap used for drywell pressure isolation signal, both the table in Appendix H and Table 6.2-2 are imprecise.
Penetration Line Valve X-23Bb Drywell Pressure V5 - 2546 X-29Bc Drywell Pressure V5 - 2547 i
X-47a Drywell Pressure V5 - 2548 i
X-47b.
Drywell Pressure V5 - 2549 X-47c POS/Drywell. Instrumentation V5 - 2230 These changes will be included with the next general update of Table 6.2-2.
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ATTACEIMENT 1 JUSTIFICATION FOR ISOLATION CONFIGURATION OF ',BCCW AND EECW LINES (PENETRATIONS X-23, 24, 34A, 34B)
These penetrations carry cooling water to all coolers in the drywell and to recirc pump seal and motor coolers.
To be conservative, all accident studies were done assuming dry-well cooling is not functioning.
However, Detroit Edison con-siders this cooling extremely highly desirable under all conditions including accident conditions.
The design of the system recognizes this importance by including drywell cool-ing in that portion of the RBCCW system which is automatically switched to the EECW system upon loss of the RBCCW.
For this same reason, the valves to drywell cooling receive no isola-tion signal.
The purpose of isolation signals is to prevent radioactivity leaving the drywell following an ace,1 dent.
Inside the dry-well, the cooling system is two sets of parallel loops; all loops but two' are Group B, Seismic 1.
The non-seismic loops are automatically blocked by loss of RBCCW plus loss of off-site power.
Outside the drywell, the cooling system is con-nected to the EECW loops.
The EECW is a Class C, Seismic 1, ESF related system.
It is maintained full of water with seismically qualified tanks and operated at pressure greater l
than LOCA pressure using pumps connected to emergency buses.
It is our contention that these features coupled with the importance of drywell cooling are sufficient criteria for these lines to remain unisolated.
l M. L. Batch
/dk l
6-15-81 l
ATTACHMENT 2 JUSTIFICATION FOR ISOLATION CONFIGURATION. OF PASS LINES (PENETRATIONS X-230, 231, etc.)
The following valves in the Post Accident Sampling System are nonessential and do not receive automatic isolation signals:
PENETRATION TITLE VALVE NO.
X-27b PASS / Containment Drywell Atmosphere Sample V13-7364 X-27b PASS / Containment Drywell Atmosphere Sample V13-7374 X-28cf PASS / Pressurized Reactor Coolant Sample V13-7360 X-43Dd PASS / Pressurized Reactor Coolant Sample V13-7361 X-48b PASS / Containment Drywell Atmosphere Sample V13-7365 PASS / Containment Drywell Atmosphere Sample V13-7375 X-210B PASS / Containment Liquid Sample Return V13-7368 PASS / Containment Liquid Sample Return V13-7378 X-215 PASS / Containment Gaseous Sample Return V13-7369 PASS / Containment Gaseious Sample Return V13-7379 X-230 PASS / Suppression Pool Atmosphere Sample V13-7367 PASS / Suppression Pool Atmosphere Sample V13-7377 X-231 PASS / Suppression Pool Atmosphere Sample V13-7366 PASS / Suppression Pool Atmosphere Sample V13-7376
ATTACEMENT 2 PAGE 2 JUSTIFICATION:
These valves are normally closed during all conditions of reactor operation.
The post-accident sampling system must, however', be available for primary coolant and containment atmosphere sampling under accident conditions.
It is also desirable to use this system during normal operation for testing and training activities.
RESOLUTION:
The resolution ct.ld be an automatic isolation valve with a key-lock bypass on the isolation cignal for each of these lines.
It is our contention that this resolution is grossly overcomplicated for such a set of small, normally-closed lines.
Instead, administrative controls will be provided which encompass the requirements of SRP 6.2.4,Section II.3.f, RG 1.141, and ANSI N271-1976.
The controls include:
- 1) a visual verification of the valve position indicating lights at least once every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; and 2) a key lock control switch that will prevent the inadvertent opening of these valves without a conscious decision on the part of the operator.
Also, the opening of these valves (whether for sampling, testing or training) will be performed only by use of specific procedures.'these procedures ensure that the operator is aware that primary containment integrity cannot be achieved in the event of a LOCA if these valves are open.
M. L. Batch
/dk 6-15-81 I
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,0 ATTACHMENT 3 JUSTIFICATION FOR ISOLATION CONFIGURATION OF RECIRC PUMP SEAL PURGE LINES One of the largest contributors to loss of reactor availa-bility is repair of recire pump seals.
We believe the risk for endangering the health and safety of the public by not isolating this line is acceptably low when compared to the unacceptably high risk of damaging recirc pump seals by loss of purge flow during isolation conditions.
The risk to the public is low for the following reasons:
I 1.
The lines are only 3/4-inch diameter 2.
So long as CRD pumps are running, no leakage is possible since the lines a/e at a pressure greater than primary system.
3.
If the CRD pumps are not running, leakage to the CRD system is prevented by check valves inside and outside containment.
M. L. Batch
/dk 6-15-81 l
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