ML19347B599
| ML19347B599 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/10/1980 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19347B600 | List: |
| References | |
| TASK-03-07.D, TASK-06-06, TASK-3-7.D, TASK-6-6, TASK-RR NUDOCS 8010150403 | |
| Download: ML19347B599 (7) | |
Text
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9 e Consumets N Power
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October 10, 1980 Director, Nuclear Reactor Regulation Att Mr Dennis M Crutchfield, Chief Operating Reactors Branch No 5 US Nuclear Regulatory Commission Washington, DC 20535 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - RESPONSE TO STAFF QUESTIONS CONCERNING PRIMARY REACTOR CONTAINMENT LEAKAGE TESTING PURSUANT TO APPENDIX J OF 10 CFR 50
References:
(1) NRC Letter From D M Crutchfield to D P Hoffman, Dated 8/4/80 (2) CP Co Letter From R B Sewell to Director, NRR, Dated 2/13/76 (3) CP Co Letter From R B Sewell to K L Coller, Dated 9/15/75 Consumers Power Company was requested in Reference 1 to provida additional information related to the implementation of 10 CFR 50, Appendix J, Containment Leakage Testing. The request resulted from the NRC review of References 2 and 3 which requested specific exemptions from some of the requirements contained in 10 CFR 50, Appendix J. to this letter provides additional information for the NRC to consider.
The Big Rock Point Plant was designed and constructed more than ten years prior to the issuance of Appendix J making conformance with all aspects of Appendix J not possible. The Big Rock Point Primary Reactor Containment Leakage Testing Program was developed on the philosophy of as close as practicable conformance to Appendix J requirements. Consumers Power Company believes that the current program provides adequate assurance of containment integrity and that approval of the exemptions, requested by References 2 and 3, will not adversely affect the health and safety of the public.
David P Hoffman (Signed)
David P Hoffman Nuclear Licensing Administrator CC Director, Region III, USNRC NRC Resident Inspector-Big Rock Point Attachment 6030150 O*"J;.
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l D M Crutchfield 1
Big Rock Point Plant October 10, 1980 i
ATTACHMENT 1 j
RESPONSES TO THE ENCLOSURE QUESTIONS OF NRC LETTER DATED AUGUST 4, 1980 NOTE: Responses Are Identified in Conformance With the Enclosure
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2.1 AIR LOCK TEST PRESSURE AND FREQUENCY Consumers Power Company proposes the following air lock testing program which requires exemptions, as stated in our letter dated September 15, 1975, from 10 CFR 50, Appendix J, Sections III.B.2 and III.D.2:
i All air locks (ie, equipment, persennel and escape) shall be tested at a frequency of every six months. The test pressure for the equipment and personnel air locks shall be at Pa which
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is 23 psig for Big Rock Point. The test pressure for the escape air lock shall be 2 psig without strongback or 5 psig with strongback in place.
The requested exemptions are required because of the emergency air lock manufacturer's restrictions on internal pressurization and the Big Fock Point Plant design which necessitates frequent personnel entries. The emergency air lock internal pressurization is limited by the manufacturer to 2 psig without strongback and 5 psig with strongback in place, thereby making pressurization to Pa impossible. Personnel air lock entries are required at a minimum of every two (2) hours for Operations personnel to conduct their normal rounds. Our submittal dated December 17, 1979 provides significant detail on the purpose and frequency of containment entries for normal rounds and other activities in its Item 1 response.
In view of the numerous entries made into containment, the emergency air lock is operated on a daily basis to assure its operation. The equipment air lock is typically used on a monthly basis to allow movement of bulky items to and from containment such as removal of spent fuel pool sock filter containers and receipt of new fuel.
The internal pressurization method used to test the air locks tends to force the doors from their seating surfaces. Thus, the equipment and personnel air lock tests provide conservative results because the door interior to containment would be forced against its seating surface in an accident resulting in containment pressurization. Tables 1 and 2 provide air lock leakage rate history since 1963. No excessive leakage rates 4
have been observed. The average leakage rate observed is about 5% (about 3% since 1974) of the maximum Technical Specifications leakage limit.
The annual preventative maintenance program, performed on all seating surfaces of the air locks which replaces seating gaskets, as necessary, has been effective in keeping leakage rates significantly below allowable limits.
Both coors of all air locks are maintained in the closed position when the air locks are not in use to provide maximum leakage protection.
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l D M Crutchfield 2
Big Rock Point Plant 4
October 10, 1980 i
In summary, Big Rock Point cannot comply with the requirement for Pa test pressure for the emergency air lock because of manufacturer restrictions.
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This is not considered a problem because its leakage rate history from j
bcth Type A (full pressure) and Type B (reduced pressure) fests has been acceptable. The requirement to perform Type B tests on air locks within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of usage places an unacceptable burden on Plant operations and provides no significant safety increase in view of the fact that no excessive leakage rates have been observed during 17 years of operation.
2.2 CLOSED SYSTEMS INSIDE CONTAINMENT l
Lines entering containment associated with the following systems were not provided with valves to serve a containment boundary function:
Service Water Heating and Cooling Service Air Instrument Air ILRT Reference Volume Shutdown Flushing Lines associated with these systems within containment were not j.
considered to be subject to rupture or leakage because they contain no high energy fluids and have no openings to the containment atmosphere which provide a path to the environment. These lines are subject to the same environment as the containment shell and are provided the same i
surveillance against leakage in that any leakags through them is accounted for as an integral part of the ILRT. As further protection against leakage, the service water system, service air and instrument air normally operate at pressures greater than the maximum pressure obtain-able during LOCA conditions.
No criteria or guidelines currently exist by which passive failures can be considered in the design of fluid piping systems (Ref:
10 CFR 50, Appendix A, Definition of Single Failure). As a result, passive failure l
of the containment shell and containment boundary piping systems is not a consideration in the design of the Plant or in the development of i
Appendix J tests.
NOTE: The air operating line penetrations (Number 6 of NRC letter dated August 4, 1980) will be eliminated during the 1980 Refueling Outage; therefore, inclusion in Appendix J test requirements will be unnecessary.
The existing mechanical penetrations will be eliminated by a facility modification which will use electrical penetrations with pneumatic /
electric and electric / pneumatic convertors for signal transfer. The mechanical penetrations will be local leak rate tested (Type C) once and then capped.
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I D M Crutchfield 3
i Big Rock Point Plant October 10, 1980 I
i 2.3 CORE SPRAY RECIRCULATION SYSTEM VALVES
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The fire system provides water to the core spray system at a pressure of j
about 150 psig. This pressure is six times greater than the maximum j
containment accident pressure of about 23 psig. A single active failure in the core spray and recirculation system will not cause a release of containment atmosphere to the environment because of the redundancy provided by the two fire pumps, diesel and electric.
4 During initial core spray while M07070 and 7071 or M07051 and 7061 are 4
j open, there will be no backflow of fire water to the fire pumps because j
the fire system pressure is higher than the accident pressure.
If M07072
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were to open, during the recirculation mode, there would be no backflow 1
of recirculation water to the fire pumps since the fire system pressure is higher than the core spray pump system pressure. Backflow of j
recirculation core spray water to the fire pumps through check valves VPI301 or VPI302, assuming failure in the open position, will not occur since the fire system pressure is higher than the core spray pump system pressure.
l In summary, the core spray recirculation system and the fire water supply i
system cannot have a single active failure that will release containment
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atmosphere to the environment because both systems are ultimately i
pressurized by the fire pumps which operate at a pressure greater than i
either the core spray recirculation system or the maximum containment j
accident pressures. The core spray recirculation system is a closed j
system outside of containment except for its two interfaces with the fire j
system at normally closed valves M07066 and M07072. Therefore, if the j
core spray recirculation system is inoperable, containment isolation is j
assured by fire system pressure applied at the two valve interfaces which j
are the only ultimate paths to the environment.
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NOTE:
1.
An assumption of normally open or closed, hand-operated isolation valves being passive components is made.
P&ID Drawing M-123 is attached for reference (Revision AE).
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!l WATER SUPPLY LINE TO THE CONTROL RCD DRIVE PUMPS AND FEEDWATER CHECK 2.4 VALVES The supply line to the control rod drive pumps will, after the 1980 3
i Refueling Outage, have two check valves which will be hydraulically tested. The line now has one check valve (VRD-310) in series with the integral checks within the CRD pumps. A second check valve will be installed in the containment side of the line to eliminate the CRD l
pumps as containment boundary. The volume available and water leakage rate limit for each valve is:
l VRD-310 - 7569.93 In* - Acceptance Criteria - 10.5. In'/h l!
New Check Valve 2063.56 In' - Acceptance Criteria - 2.87 In'/h i
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D M Crutchfield 4
Big Rock Point Plant October 10, 1980 Appendix J exemptions for the two globe check valves in the feedwater system are no longer required. Prior to 1977, these valves were not local leak rate tested. Since that time, a method has been developed to local leak rate test with air.
The first air test occurred in September 1977. The air test frequency is each reactor shutdown for refueling but not to exceed 18 months (based upon Appendix J require-ments).
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i TABLE 1 b
BIG ROCK POINT NUCLEAR PLAST Contaiment Air Lock Leakage Rate History Prior to May 1976 s
Date Equipment Lock Personnel Lock i
Pounds /24 Hours Pounds /24 Hours 4/ 4/63 11.7 261.0 9/22/63 32.404 52.56 10/10/63 0.0 11.632 2/12/64 23.608 25.091 2/22/64 31.764 3.895 4
5/20/64 24.62 10.342 i
8/21/64 16.58 10.14 2/ 9/65 12.80 23.78 8/24/65 87.467 0.7997 2/ 5/66 0.0 2.3-l 8/13/66 16.0 1.34 2/21/67 48.55 17.55 8/18/67 0.0 7.9 3/ 4/68 0.0 0.0 9/ 9/68 0.0 34.2 j
4/ 2/69 32.30 7.73 10/14/69 61.6 6.75 4/14/70 1.44 6.08 l
10/11/70 70.865 1.44 4/14/71 121.29 6.95 10/11/71 133.11 0.0 3/ 7/72 42.52 3.38 11/ 6/72 26.40 4.95 4/25/73 32.9 8.5 10/ 8/73 27.66 4.83 3/22/74
-18.84 4.84 9/30/74 13.9 6.7 3/22/75 31.74 52.07 3/27/75 8.69 17.42 4/27/75 8.74 17.42 9/22/75 20.55 4.9 4/21/76 12.63 1.7 I
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NOT_E: The Technical Specifications Total Leakage Rate Limit Is Around 450 Pounds /24 Hours (Appendix J - 500 Pounds )
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TABLE 2 BIG ROCK POINT NUCLEAR PLAST Containment Air Lock Leakage Rate History Since May 1976 Personnel Lock Equipment Lock Escape Lock Leak Rate Leak Rate Leak Rate Date Lb/24 h Date Lb/24 h Date Lb/24 h 11/20/76 0.0 11/20/76 1.30 11/21/76 12.4 5/19/77 0.3 5/18/77 2.8 5/19/77 7.2 1/11/78 5.1 3/14/78 30.1 3/15/78 0.2 7/11/78 2.1 10/10/78 0.0 10/ 7/78 0.5 1/20/79 19.5 1/27/79 2.5 1/23/79 1.5 8/28/79 10.0 8/29/79 3.0 8/30/79 3.0 4/16/79 3.0 4/17/80 0.0 2/19/80 0.0 4/16/79 1.5 4/29/80 35.5 4/19/80 0.0 4/29/79 3.0 NOTE: The Techrical Specifications Total Leakage Rate Limit Is Around 450 Pounds /24 Hours (Appendix J - 500 Pounds )
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