A02163, Submits Comments Re Draft Evaluation of SEP Topic VI-4, Containment Isolation
| ML20054D189 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/14/1982 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR A02163, A2163, NUDOCS 8204220424 | |
| Download: ML20054D189 (5) | |
Text
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1 RECEIVED Docket No. 50-245 23 APR 2 21982> 9 A02163 s n:wd Eam numan m ean m o m eg a N
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Director of Nuclear Reactor Regulation g
Attn:
Mr. Dennis M. Crutchfield
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Chief Operating Reactors Branch #5 U. S. Nuclear Regulatory Commission Washington, D.C.
20555
References:
(1)
D. M. Crutchfield letter to W. G. Counsil dated December 9, 1981.
(2)
W. G. Counsil letter to D. M. Crutchfield dated November 6, 1980.
(3)
D. C. Switzer letter to G. Lear dated July 29, 1977.
Gentlemen:
MILLSTONE NUCLEAR POWER STATION UNIT NO.
1 SEP TOPIC VI-4, CONTAINMENT ISOLATION Via Reference (1), the Staff forwarded the draft evaluation for SEP Topic VI-4, Containment Isolation, for Millstone Unit No. 1.
Northeast Nuclear Energy Company (NNECO) has reviewed Reference (1) and offers the following comments.
The following are general comments on Section VI of Reference (1).
All testline valves are closed per procedure following 10 CFR 50 Appen-dix J 1eak rate testing. There are no administrative controls or loc-i king devices on the normally closed manual valves in penetrations X-9B, X-12, X-14, X-17, X-39 and X-211.
There are no administrative controls on the locked closed manual valves of penetrations X-7, X-8, X-10A, X-16, X-20, X-41 and X-42.
Penetrations X-9 and X-42 deviate from General Design Criteria (GDC) 55 since they include the use of check valves outside containment. Reference (1) directs our attention "to one of the more significant issues contained in the conclusion, the use of a simple check valve as an isolation valve outside containment. The item appears to contradict the explicit wording of the regulations
." Notwithstanding the technical discussion of this issue which follows, NNECO contends that the above quotation is not fo 8204220424 820414 Gh6 PDR ADOCK 05000245 P
P an accurate characterization of the status of compliance with applicabic regulations for Millstone Unit No. 1.
The General Pesign Criteria of Appendix A to 10CFRSO were published on February 20, 1971, well after the POL for Millstone Unit No. 1, DPR-21, was issued.
It has been and remains NNECO's intention to comply with the GDCs to the extent appro-priate.
It is, however, recognized in Appendix A that departures from the GDC's are acceptable.
Portions of the remainder of this letter clu-cidate the basis for NNECO's position that these departures are accept-able. Notwithstanding the fact that Millstone Unit 1 began operation before the GDC's were promulgated, GDC 55 expl.icitly allows deviations if ".
it can be demonstrated that the containment isolation pro-visions for a specific class of lines
. are acceptable on some other defined basis
." Feedwater coolant injection and the standby liquid control systems are essential ESF systems.
Simple check valves provide greater asssurance than automatic valves that these systems will supply fluids needed for safe shutdown.
NNECO has concluded that these check valves increase the probability of proper ESF system operation and still provide edequate containment isolation.
A discussion of the automatic features of the penetration X-210 isola-tion valves is li.cluded below in the comments on Table 1 of Reference (1).
Reference (2) describes modifications to X-23 and X-24 planned for a future refueling outage to fully meet the GDC's.
Reference (2) also describes modificatons that will make it possible to detect leakage through the penetration X-204 containment isolation valves. With these modifications, closed portions of the containment and core spray systems meet SRP Sections 6.2.4.II.6.b, e and f except as stated below. The missile vulnerable sections of trains B and D are marked in red on the attached drawing 25202-26008. Trains A and C are similar. The motor bearing cooling coil return lines connect to line numbers 20"-cc-la and 20"-cc-lb.
These small lines contain normally-open manual valves since the cooling water is essential for proper ESF system operation.
All instrument sensing lines that contain excess flow check valves are part of the reactor protection system. The following table shows the dose (in Rem) due to the rupture of one of these lines that was calcu-lated similar to calculations for SEP Topic XV-16.
THYROID WHOLE BODY 0-2 Hr. EAB 25.49 0.420 0-4 Hr. LPZ 26.91 0.263 10CFR100 Guideline 300.
25.
These doses are acceptable as they are substantially below the guidelines of 10CFR100.
Both current and planned Icak detection provisions are discussed in Reference (2) for penetration numbers X-16, X-24, X-43, X-204 and X-211.
P 3-Penetrations X-39, X-210 and X-211 contain only single containment isolation valves in series per Reference (2).
Penetrations X-25 and X-26 do not include a leak-tight or controlled leakage housing between the containment and the innermost containment isolation valve.
This portion of the system normally remains below the minimum pressure and temperature used to define a high energy system per SRP Section 3.6.2.
It also does not carry water or steam during normal operation.
The Following General Comments Apply to Table 1 of Reference (1)
Many valves that are not containment isolation valves are listed in Table 1.
These valves should be deleted so that Table 1 agrees with the list of containment isolation valves provided in Reference (2).
Additional information was requested on all seal welded penetrations and double gasketed seals such as spare penetrations, thermowells, and hatches. Reference (2) adequately describes the isolation provisions of these penetrations.
Some manual and motor-operated valves are listed as failing open or closed due to power failure. These valves all fail as is.
Check valve position depends on system demand at the time.
Reference (2) describes some active projects that will affect isolation provisions of some penetrations.
- The following specific comments apply to Table 1 of Reference (11 PENETRATION NO.
COMMENT X-8 The gate valves are 4-inch, not 2-inch valves.
X-10A & 11A The gate valves close on a group 4 isolation signal.
See Table 3.7.1 of the Technical Specifications.
X-12 Valve 1001-1 is normally closed.
X-14 A new valve, 1-CU-2A, was recently installed inside containment to bypass 1201-2.
This is an air-opera-ted globe valve which is closed during normal opera-tion, shutdown, post LOCA and power failure condi-tions.
It is not essential and closes on a group 3 isolation signal.
Reference (2) will be revised to reflect the following:
X-42 Valve SL-7 is the containment isolation valve (instead of SL-8).
e X-212 This penetration contains only one containment isolation valve (CU-69), instead of two valves.
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X-16A, B The check valves are closed during normal and shut-down conditions but are open during LOCA core spray operation.
X-17 Head cooling is also used to achieve cold shutdown.
X-21 The service air penetration includes a remote manual motor-operated gate valve outside containment that is open only during refueling and a check valve inside containment. See attached drawing 25202-26016.
X-22 The instrument air penetration includes a remote manual / motor-operated gate valve outside containment that is always open. One check valve inside and one outside containment open on air demand.
X-23, 24 See comments on Section VI of Reference (1), above.
X-25, 26 These butterfly valves may be opened or closed during normal operation and shutdown due to purging.
X-35 The isolation valve is automatic only if the TIP's are out.
References (2) and (3) discuss the iso-lation arrangement and NNECO's plans for modifying this penetration.
X-39A, B The motor-operated valves are not automatic. The test line valves are always closed except during local leak rate tests.
X-41 These solenoid-operated valves are automatic and close on a Group 1 isolation signal.
X-43, 45 The air operators were designed to stroke the check valves open for testing purposes. These are not remote / manual stop check valves. The air operators have been disabled and the valves act as simple check valves.
X-201, 202 See attached drawing 25202-29112, Sheet 80.
X-203 These valves may be open or closed during normal operation and shutdown.
X-204 This penetration is essential. The motor-operated valves are open during shutdown and post-LOCA. Page 11 of Reference (1) discusses pipe caps and two closed manual valves in series. These components do' not exist in the piping between the torus and the containment isolation valves. See attached drawing.
25202-26008.
I X-205-See Reference (2) and attached drawing 2502-26009 for details.
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X-206 See attached drawing 25202-28008 for details.
X-207 These lines drain the low points of the downcomers into the torus, and are entirely contained within the torus. Since they do not provide a leakage path outside primary containment, no isolation capability is required. See attached drawing 25202-26008.
X-208 These lines do not penetrate primary containment.
See attached drawing 25202-26008.
X-209 It is not clear what additional information is needed since these penetrations are seal welded and do not fall under any of the applicable GDC's.
X-210 Valves 1501-36A, B are not containment isolation valves per Reference (2). Valves 1501-35A & B and 1501-36A & B are the LPCI test to torus line iso-lation valves. They do not receive a containment
+
isolation signal but, if open at the time, will close upon receipt of a LPCI initiation signal.
When flooding of the core is completed, the valves will be remotely opened to provide post-LOCA long-term cooling of the torus water. Valves 1501-18A, B are on minimum flow lines and close when the con-tainment spray pumps achieve sufficient flow.
X-211 Valves 1501-37A, B are always closed except during containment spray to the torus.
NNECO has concluded that the balance of the Staff's evaluation is fac-tually correct. We trust the Staff will appropriately incorporate these comments into a revised Safety Evaluation Report for the SEP topic.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY 8[
l W. C.' Counsil Senior Vice President i
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