ML20002C811
| ML20002C811 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 05/17/1978 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20002C810 | List: |
| References | |
| NUDOCS 8101120058 | |
| Download: ML20002C811 (3) | |
Text
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ATTACHMENT t'
Special Riport No.
27
~O Reactor Centainment su11 dins Intes=ated tesx Rate Test APPENDIX 3 TECHNICAL JUSTIFICITION FCR NEXT SCHEDULED ILRT BEING IN 1950-1981
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.a The purpose of this adAlysis is to provide technical justification for' the next proposed contain=ent integrated leakage rate test. The proposed date is about 3-1/2 years after the Septe=ber, 1977, ILRT, which is late 1980 or for this analysis is 10CFR50, Appendix J and the last early 1981. The basi 9 two containment ILRTs results (197h and 1977).
In Section A.6.b of Appendix J, it states:
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"If two consecutive periodic type A tests fail io'=eet the applicable acceptance criteria in III-A.5 (b), not with-steMng the periodic retest schedule of III.D,a Type A test shall be performed at each plant shutdown for refueling or approximately 18 =onths" NOTE:
III.A.S.b is: Acceptance criteria - (1) Redue.ei pressure tests. The leakage rate Lts sha3.1 be less than 0.75 Lt.- If local leakage '=easu're=ents are taken to effect repairs in order',to =eet
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the acceptance criteria, these =easure=ents shall be taken at a test pressure-Pt.
(2) Peak pressure tests. The leakage rate
- Lam shall be less than 0.75 La.
If local leakage =easurements are taken to effect repairs in order to =eet the acceptance criteria, these =easure=ents shall be taken at a test pressure Pa.
AND III.D is:
Periodic retest schedule - 1.
Type A test.
(a) After the preoperational leakage rate tests, a set of three Type A tests shall be perfor=ed at approxi=ately equal intervals during each 10-year service period. The third test of each set shall be conducted when the plant is shutdown for the 10-year plant in-1 service inspections.
t (b) Per=issible periods for testing. The perfor=ance of ?ype A tests shall be limited to periods when the plant facility is non-operational and secured in the shutdown condition under the ad=inistrative control
- and in accordance with the safety procedures defined in the license.
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i ATTACHMENT Specini R2 port Na 27
'Resctor Contain=ent Building Integrated Leak Rate Test Appendix 3 (contd)
During the last two contain=ent leak rate tests, the excessive leakage rates encountered vere due to a single component (197h - supply ventilation butter-fly valve; 1977 - feedvater check valve) which was.th' n repaired and test e
results proven acceptable.
In the 197h ILRT, a leakage rate of.309%/ day was experienced during the first hold test. This leaka$e rate is al=ost double the Technical Specification li=it of.lT5%/ day. Quoting from page h and 5 of the 197h ILRT Report:
"Upon investigation for the source of the high =easured leskage rate, it was discovered that the 2b-inch butterfly valve cin the supply ventilation line into the contai cent building was leak-ing at the contai=ent-side flange. This valve had been installed during the shutdevn prior to conducting the leak n ate test. An esti= ate of the leakage rate was made by colli =ating the air flow through a one-inch diameter (I.D.) pipe and measuring the velocity profile across the pipe. The leakage rate through the flange was esti=ated to be 0.292%/ day. Hence, essentially all of the leakage
=easured during the first hold test was through the supply vent butterfly valve contain=ent side flange.
Bolts were tightened around the flange and the 1;e'akage stopped.
The contain=ent pressure was increased to appro'xt=ately 8 inches of H O above the reference system and conditions. vere allowed to 2
stabilize for four hours prior to initiation of the second hold test."
This po:-tion of the 197h test report related the fact that the 2k-inch supply ventilhtion butterfly valve contain=ent side flange vas leaking through at the rate which was observed in the first hold test. Thus, by tighteni=g down on the bolts around the flange, the leakage stopped. (Note the resultant contain=ent leakage rate of.0755/ day was still within the
.75 L li=1t.) The valve had been installed during the sa=e outage the inte-gratekle*ageratetestwasperfor=ed. The ILRT essentially acted as an in-stallatics acceptance test for the valve, especially the contain=ent side flange.
The 1977 cc= tai =ent integrated leak rate test was the first contai=ent test that was i= full co=pliance with 10CFR50, Appendix J.
Draining and venting of several syste=s to atte=pt a close approximation of syste= status after an acnident was perfor ed in preparation for the test. The feedvater syste= vas one syste= in which a leakage path was found.
The. leakage path was through two fee:! vater check valves. The feedvater syste=
vas then isolated and after the co=pletion of the test, the leakage rate through the check alve was determined, utilizing the pressurized contai=ent as a source of air.
'~ne check valve leakage was =easured with a gas flov meter attached to 4
the feedvater'line to obtain the magnitude of the leakage.
The feedvater line leakage path was detected approxi=ately half way through the controlled leakoff portion of the ILRT. Exa=ination of test results at that time indicated a leakage rate greater than expected in the controlled leakoff portion.
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ATTACHMENT
(
j 27 Special Rsport No.
Reactor Containment Building Integrat;d Leak Rate Teat Appendix 3 (contd).
In turn, investigation of the leakage resulted in the conclusion that the feed-The feedvater'line was then isolated.
water check valve was leaking through.
Thus, the initial hold test was considered invalid and corrective action was taken to continue with the contain=ent test' 3 In conclusics, as a result of the excessive leakage rate encountered, due to the feedvater check valves, and the evidenes presented above, this ILRT is considered to be the first ILRT failure. Thus, if the ILRT in 1980 81 re-sults in unacceptable results, then III.A.6(b) applies.
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