ML20004E203
| ML20004E203 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 06/09/1981 |
| From: | Colbert W DETROIT EDISON CO. |
| To: | Kintner L Office of Nuclear Reactor Regulation |
| References | |
| EF2-53496, NUDOCS 8106110341 | |
| Download: ML20004E203 (2) | |
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June 9, 1981 EF2 - 53496 Mr. L. L. Kintner U. S. Nuclear Pegulatory Comission Division of Prcject Management Office of Nuclear Reactor Pagulation 7929 Norfolk Avenue Bethesda, Marylard 20014 Paference: Enrico Fermi Atomic Power Plant, Unit 2 NPC Docket No. 50-341
Subject:
Oral Questions on Containment Isolation Decendacilit/
Dear Mr. Kintner:
The following is in response to oral questions from John Lane, N3C, on Section II.E.4.2 of FSAR Apperdix H.
His first concern was that some rcnessential lines 3.isted only one (instead of tm) safety grade diverse isolation signals in FSAR Table H.II.E.4.2-1.
This taale was composed recognizing only tm isolation signals:
reactor low level ard high drywell pressure. In every case where onc of these signals was wrong to use (since it muld interfere with proper operation of the system), alternate sig-nal(s) or justification are given under Coments. We believe all non-essential lines are isolated by safa.ty grade diverse isolation signals or are adequately justified.
, In the case of penetration X-7A, main steam lines, six other isolation signals are listed. In the case of penetration X-17 and all other lines connected to icw pressure systers (LPCI ard CS), the table fails to point out that these isolation valves are interlocked closed at reactor pressures above swa low value. Consequently, all these lines will be closed at the time of the accident ard, therefore, do not need signals to cause isolation.
Mr. Lane's second concern was that the latest NPC position for essential sample lines require automatic isolation. He sites penetration X-48d as an example. We offer the following arguments to justify the absence of autmatic isolation.
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o Mr. L. L. Kintner June 9, 1981 Page 2 1.
Instrument and sample lines classified essential are classi-fled essential W au w they may be needed to monitor the course of an accident following containment isolation.
Therefore, isolating on a IOCA would. interfere with their safety function.
2.
Sample lines are normally closed.
3.
Sample lines are in a system classified as a closed loop out-side containment. Requirements met lyf st;:h a system include missile protection, Seismic Category 1 and Cuality Group 3 1
design standards.
Very truly yours,
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W. F. Colbert Technical Director Enrico Fermi 2 hTCA!IB/dk V
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