ML19274F944
| ML19274F944 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 07/20/1979 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-06, TASK-6-6, TASK-RR NUDOCS 7908270190 | |
| Download: ML19274F944 (12) | |
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jo UNITED STATES g
NUCLEAR REGULATORY COMMISSION 3
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., C WASHINGTON, D. C. 20555
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JUL g1) p79 MEMORANDUM FOR:
D. Ziemann, Chie.f, bperating Reactors Branch #2, Division of Operating Reactors FROM:
G. Lainas, Chief, Plant Systems Branch, Division of Operating Reactors
SUBJECT:
LACROSSE BWR - CONTAINMENT LEAK TESTING (TAC 8858)
Plant Name: Lacrosse Docket No.:
50-409
' Project Manager:
J. Shea Reviewing Branch: Plant Systems Branch Status:
Incomplete; will require additional information The Plant Systems Branch (PSB) has reviewed the LACBWR's submittal dated December 21, 1976, which was in response to a NRC letter dated December 8,1976 regarding containment leak testing. Our evaluation of the submittal indicates that two of four responses require additional infonnation.
1.
For certain Type C tests, using wa'ter as test media in lieu of air,is unacceptable unless appropriate justification is provided by the licensee and approved by the NRC staff.
2.
Testing containment airlock door every four month interval in lieu of within 3-days after a series of door usages is unacceptable unless the integrity of airlock doors can be demonstrated by means other than testing after each use.
Y. Huang of the PSB has discussed the above matter with the responsible personnel of the De ryland Power Cooperative (DPC). They indicated that the DPC would prepare the additional infonnation and requested that a
meeting be arranged with the NRC staff to resolve these issues.
Please arrange the requested meeting as soon as possible. The DPC also requested a copy of D0R position on the implementation of containment leakage testing requirements to operating plants. Attached is a copy of the requested document.
f G. La
, Ch ef Plan stems Branch Division of Operating Reactors 700827030*
Contact:
Y. Huang, X27173 cc w/ enclosure:
O. Eisenhut B. Grimes W. Gammill E. Adensam.
G. Lainas J. Shea H. Wong Y. Huang
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IMPLEMENTATION OF CONTAINMENT LEAKAGE TESTING REQUIREMENIS (APPENDIX J TO 10CFR50) TO OPERATING PLANTS 1.
Containment Air-Cock Testing (Section III.B.2 and III.D.2)
Appendix J,Section III.B.2 requires (a) that Type B tests shall be performed at a pressure not less than Pa, and (b)Section III.D.2 requires that. air locks be tested at 6-month intervals and air locks which are opened during such intervals be leak-tested af ter each opening.
BACKGROUND:
Based on plant operating experience, the requiremant that air locks be leak-tested af ter each opening is an i= practical r.equirement when frequent ai,r lock usage is necessary over a short period of ci=e.
Testing the air locks 13.. for leakage.within.a.lisi,ted time period fo11cving the initial opening is more practical, and still provides the desired confidence in the leak tightness
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of the air lock. The proposed position allows air locks to be tested within three days following an opening.
So'=e operating plants designed prior to the issuance of Appendix J do not
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have the. capability to test the air locks at Pa as required by Appendix J.
By subjecting the air locks of. these plants to an internal pressure of Pa for~ the local leakage tests, the inner _ air lock door is lif ted off its seat and allows significant leakage into the contain=ent. Ihis condition does not permit a realistic assessment of the air lock leakage rate, sitae the contain=ent pressure under LOCA conditions would act in the oppcsit' I
direction and terd to seat the inner air lock door. To prop,erly deter =ine s
the leakage rate, strongbacks cust be fastened to the inner air lock door.
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m s-12+.:- This is a time consuming task, and for frequent openings, is an impractical requirement. The proposed position allows the air lock to be tested at the manufacturer's recoc=iended maximum test pressure for tests other than the six-month test.
POSITION:
When containment integrity is required, an air lock shall be tested within three days af ter being opened; When multiple entries are required, the air lock shall be tested' within three days af ter the initial opening. The test pressure shall be applied between the doors, or in the case where dual seals are incorporated in the door design, the test pressure may be applied between the seals.
in the event t,esting cannot be performed at Pa due to, tha. design of the air lock, the test may be performed at the manufacturer's
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E recocmendedcaximum test pressure.
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.4 Air locks which cannot be tested at Pa after being opened when containment integrity is required without the use of mechanical' devices to seat the doors, shall be tested between the doors at Pa at six-month intervals utilizing such.
devices.
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BASES:
Testing experience'to date indicates that contain=ent air lod.s are reliable components with respect to leak tightness. The require:ent to leak test air locks af ter each opening at peak accident pressure is censidered to be an impr'actical requirement.
Considering that a full pressure air lock test is performed every 6 months, it is our judgement that testing air locks within
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three days after each opening and/or at the manufacturer's recommended pressure
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-"' ' will de=onstrate adequately the continuing integrity of the air lock door seals such that the public health and safety will.be ensured. We see little effect en accident probabilities for each opening and a three day test.
If a leak path is developed at the test, it will be manifested at either the manufacturer's or other pressure. This is adequate demonstration for interim testing.
2.
Isolation Valves which Require Leak Rate Testing (Section II.H.)
Appendix J,Section II.E states that the containment isolation valves included' in the " Type C Tests" are those that:
1.
Provide a direct connection between the inside and outside at=ospheres of the pri=ary reactor containment under nor'=al operation, such as purge, and ventilstion, vacuum relief, and instrument valves; N1==2.
Are r,equired to close automatically upon receipt of a containnent isolation signal in response to controls intended to effect containment isolation; 3.
Ire required to operate intermittently under post-accident conditions; and
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4.
Are in main steam and feedwater piping and other systems idtich penetrate containment of direct-cycle boiling water power reactors. ~
BACKGROUND:
Type C tests are tests intended to =easure contain=ent isolation valve leak rates.
However, the above definitions of Appendix J are not consistent with the contain-cent isolation valve require =ents of General Design Criteria 54, 55, 56, and 57.
As an example, the main steam and feedvater valves of PWR type pl, ants would be con'sidered isolation valves in accordance with GDC 57 (Closed Syste=s Isolation Valves) but are specifically.. excluded by Appendix J.
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=~ POSITION:
Licensees can limit Type C testing to those valves as defined by Paragraph II.H. of Appendix.J.
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BASES:
We are proposing to resolve the inconsistency between Appendix J end GDC in i
a future revision to Appendix J; however, we do not believe that license es
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should be faulted because of inadequacies in the r, gulations, and should, e
therefore define the isolation valves that require leak testi;1g in accordance with Appendix J,.
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BWR Main Steam Isolation Valves (Section III.C.2)
- Ie Appendix J,Section III.C.2 requires that valves, unless pressurized with a
%.5 57-fluid from a ceal system shall be pressurized with air or nitrogen at a
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pressure of Pa.
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BACKGROUND:
System design for most BWR main steam systems does not per=it leak testing of th'e main steam isolation valves at Pa.
The method for testing' requires appli-
.2 cation of test pressure between the M.S.I.V's since an additional barrier
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upstream of the inner isolation valve is not provided.
Iesting between the d
valves tends to unseat the inner valve at a pressure less than Pa resulting n
in leakage into the reactor. The lic~tsees contend that even though the test pressere is less than Pa, the test of the inner valve is conservative since the test pressure tends to unseat the inner valve while containment tt
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accident pressure tends to seat the valve and make it more leak-tight.
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The proposed position considers M.S.I.V's for BWR's to be a special case ee-*
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EEF for which testing criteria should be provided in the Technical Specifications rather than Appendix J.
7 POSITION:
.For nain steam isolation valves in boiling wat' r reactors, a leak rate test e
E pressure less than Pa is acceptable. The test pressure shall be as stated
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in the Plant Technical Specifications,.
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BASES:
' Two isolation valves are provided in series in each main steam line but only
.one valve is required to maintain containment integrity.
The leak test method
. conservatively neasures the valve leakage.
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Leak Testing Isolation Valves in Direction of Safety Function (Section III.C.1)
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ISE Appendix J,'Section III.C.1 requires that for. Type C testing of isolation valves,
the test pressure shall be applied in the same direction as that when the valve
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would be required to perform its safety function unless it can be determined that the results from the tests for a pressure applied in a different direction will provide equivalent or more conservative results.
3 BACKGROUND:
Most operating reactor plants designed and constructed prior to the issuance
' :1 ppendix J, did not provide the.necessary system design features such as of additional valves to permit leak rate testing of isolation valves in the direction of the safety function., The licensees conteed that testing in the reverse direction for certain types of valve design; i.e., butterfly er globe, will provide conservative resylts and as such are acceptable tests in accord-ance with Appendix J.
For certain valves such as globe valves where pressure
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- applied in the.everse direction during a test may unseat the va ve; t e conservative results are obvious. For other valves such as butterfly, gate or diaphragm it is not so obvious. The proposed position requires the licensee to demonstrate the conservatism for the individual valve design or to provide system changes to permit testing in the direction as. stated in Appendix J.
5 POSITION:
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Type C tests performed with the pressure applied in a reverse direction from
. the direction of safety function will be considered to meet the requirements of Appendix J,Section III. Col when it can be demonstrated for each valve design that the leak test results are equivalent or more conservative than those test results obtained during testing in the direction of the containment function.
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BASES:
(Not Required) 5.
Hydrostatic Testing Isolation valves (Section III.C.2.a)
Ap'pendix J,Section III.C.2.a requires that valves, unless pressurized with a seal system, shall be pressurized with air or nitrogen at a pressure of Pa.
BACKGROUND:
In order to ecmply with this requirement of Appendix J, it is necessary to drain fluid systems or portions of systems to expose the isolation valves to the test fluid (air or nitrogen). Much time and effort is required to do this, and provisions for storage of radioactive liquids are frequently required and in some cases this capabi,lity was not designed into the syste=s of plants Si designed before Appendix J was published. The proposed position permits i
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-== hydrostatic testing of isolation valves if certain system design requirements and liquid leak rates are included as such in t'_ caciological dose are met, analyses.
POSITION:
Appendix J requires air or nitrogen to be used as the test fluid for conducting Type C tests which necessitates draining liquid-filled systems. SI'his require-ment is intended to simulate the condition of the system following a postulated loss-of-coolant accident (LOCA) where the leakage _ barrier,s (e.g., valves, There are gaskets, and seals) may be exposed to the containment at=osphere.
a number of ' liquid-filled syste=s; however, that are specifically designed to remain intact following a LOCA. These include; e.g.,
the e=ergency core cooling system, the containment heat removal systems, and feedwater systems.
55 For those' systems that are designed to engineered safety feature criteria and
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which wiil either operate or provide assurance that the system will be liquid '
filled following a LOCA, ljiquid leakage should b_. distinguished.from contain,-
e ment atmosphere leakage. Therefore, these systems can be hydrostatically tested to de=onstrate that the fluid inventory is sufficient to maintain a water seal for the duration of the accident, and a_ liquid leakage limit, can,
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be assigne,d for these systems,. This criterion is similar in concept to a valve seal-water system criterion and will provide equivalent isolation protec-tion.
Radiological analysis should be performed to demonstrate that liquid leakage lwes do not result in doses exceeding Part 100.
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3ASES:
Leakage limits established by $ydrostatic testing of fluid systens. designed
- to engineered safety feature criteria which remain intact and filled'vith water following a LOCA provides an acceptable alternate nethod of Type C testing isolation valves.
6.
Local Leak Repair During Type A Test (Section III.A.l.a)
Appendix J,Section III.A.l.a requires that if during a Type A test, potentially excessive leakage paths 'are identified which will interfere with satisfactory complction of the test or which will result in the Type A test not meeting the acceptance criteria, the Type A test shall be terminated and the leakage through such paths shall be measured using 1 cal leakage testing =ethods.
Repairs and/or adjustments to egizipment shall be made and a' Type A test f5i" shall be performed.
BACKGROUND:
During containnent integrated leakage rate testing of several plants, local leak rate tcsting and repair of leak paths have been performed and the results This the Type A test revised to incorporace the local leak test results.
o procedure. is in variance.vith Section III.A.l.a of Appendix J.
Appendix J requirenents have also been interpreted such that local leakage rate testing prior to Type A testing is not permitted.
Considerable loss of operating time and expense results from the interruption of a Type A test if local leak paths are identified and cannot be isolated or repaired during the Type A test.
s POSITION:
identifiable local leakage occurs If, during the perfor=ance of a Type A test,
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"*"' to the extent that it could cause failure of the Type A test, e.g., through penetrations or isolation valves, the leak may be isolated and the Type A test continued until completion.
Subsequent to the cci letion of the Type A test, Type B or C testing of the isolated leaks shall be conducted and the measured leak rates added to the w
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., Type A test results.
However, the difference in Type B and C 1:est results before and af ter the repair 'of local leaks n y not be deducted from' the Type 1 cesc result in order to achieve an acceptable contain=ent integrated leak rate.
If the addition of the local leakage to the 5ype A test leakage results in a
.3 total measured leakage (Lam) which exceeds 0.75 La or by including the 95
_... percent c,onfidence interval, exceeds La, the Type A test shall be repeated.
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Type B and C leak rate testing and repair prior to containment I.L.R.T. is also considered to be acceptable,.
BASES:
Isolation of local leaks during the containment I.L.R.T. and~ subsequent adjust-ment of the Type A test result through supplementary local-leak rate testing
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will reduce the overall pl. ant downti=e devoted to containcent integrated leak i
rate testing without increasing risk to the health and safety of the public and without affecting the end result of the contninnent I.L.R.T.
J 7.
Centain=ent ?enetration Leak' Testing (Section II.G and III.D.3) (Personnel air locks excepted)
. Appendix J requires that con ain=ent penetrations whose design incorporates resilient seals, gaskets, sealant compounds, piping penetrations fitted with
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e 5 metal seal assenblies, shall be tested to detect local leaks at each refueling, but in no case at intervals grea'ter than two years at Pressure Pa.
(Personnel air locks excepted).
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BACKGROUND:
Certain reactor plants constructed prior to the issuance of Appendix J did y
i not provide the design capability for performing Type B tests for various
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POSITION:
j For those plants in which typical penetrations such as equipnent hacenes, penetration bellows, or electrical penetrations are not designed to permit local leak testing, these penetraticas shall be tested in conjunction with the Type A containnant integrated leak test as specified in the Technical
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W Specifications.
.i BASES:
.s Testing experience to date indicates that there is no significant increase in leakage through the penetrations.
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