ML20040A640
| ML20040A640 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 12/31/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | NRC ATOMIC SAFETY & LICENSING APPEAL PANEL (ASLAP) |
| References | |
| TASK-AS, TASK-BN-81-20, TASK-BN-81-22, TASK-BN-81-23, TASK-BN-81-57 BN--81-20, BN--81-22, BN--81-23, BN--81-57, BN-81-20, BN-81-22, BN-81-23, BN-81-57, NUDOCS 8201210332 | |
| Download: ML20040A640 (9) | |
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December 31, 1981 HEIG ANDUM FOR: The Ato.r.ic Safety and Licensing Appeal board for McGuire Nuclear Station, Units 1 and 2 FROM:
Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
SUBJECT:
BOARD NOTIFICATION - EPRI TEST DATA O!! CONTROL COPPONENTS INTERNA 110NAL (CCI) POWER OPERATED RELIEF VALVES (PORV) (BN-81-57)
The enclosed aenerandum froa; R J. Bosnak to R. A. Birkel dated Decenter 22, 1981, outlines the safety significance of certain test results previously provided with-out evaluation to the Appeal Board by Board Notices BN-81-20, BN-81-22, BN-61-23, dated August 11, August 26, and Septeaber 2,1981.
As discussed in the enclosed nemoranduin, the staff does not believe that these test results are of adverse safety significance to operation of the McGuire facil-ities.
Orly)nst signed by Re,-art p Ted m --
Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
Enclosure:
Memoranduia f roia R. J. Bosnak to R. A. Birkel dated Deccater 22, 1981 8201210332 811231 PDR ADOCK 05000369 P
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%9....,o DEC 2 21981 MEMORANDUM FOR:
Ralph A. Birkel, Senior Project. Manager Licensing Branch #4, DL FROM:
Robert J. Bosnak, Chief Mechanical Engineering Branch, DE
SUBJECT:
SAFETY SIGNIFICANCE OF EPRI TEST DATA APPLICABLE TO CONTROL COMPONENTS INTERNATIONAL POWER OPERATED RELIEF VALVE
Reference:
December 15, 1981 memorandum from R. Birkel to R. Bosnak The referenced memorandum refers to three Board Notifications that were trans-mitted by DL to the McGuire Atomic Safety and Licensing Appeal Board.
Each of these notifications contained a letter from DE to DL and transmitted valve test results obtained from the EPRI PWR valve test program being performed pursuant to item II.D.1 of NUREG-0737.
Board notification #BN-Si-22 transmitted a March 27, 1981 memorandum from R. Vollmer to D. Eisenhut and attached results of PORV and PORV block valve tests. The test results transmitted with this DE memorandum indicate that the PORV and block valve of the type used on the McGuire facility passed all applicable screening criteria.
Board notification #BN-81-20 and #BN-81-23 were transmitted respectively by memoranda dated July 1, 1981 and July 16, 1981 from J. Knight to R. Tedesco and T. Novak. Both of these memoranda transmitted test results which are applicable to a Control Components, Inc. PORV of the type used on the McGuire facility. The transmitted test results indicate that this test PORV did not pass one of the test screening criteria in a few of the test sequences.
Per your request in the referenced memorandum, with the assistance of the Reactor Systems Branch, DSI, we have performed an evaluation of the safety significance of the PORV test results transmitted with the July 1, 1981 and July 16, 1981 memorandum from J. Knight as they relate to the McGuire facility.
The evaluation is contained in the attachment to this memorandum.
Robe t J. Bosnak, Chief Mechanical Engineering Branch Division of Enginraring
Attachment:
As stated cc: See next page.
I cc w/att.:
R. Vollmer E. Sullivan E. Adensam E. Ketchem
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J. Knight i
F. Cherny H. Gregg J. Mazetis i
W. Jensen F. Orr Z. Rosztoczy 4
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SAFETY EVALUATION MCGUIRE UNITS 1 & 2 CCI - PORV TEST RESULTS - TRANSMITTED TO DL BY JULY 16, 1981 AND AUGUST ll, 1981 MEMORANDUM FROM J. P. KNIGHT In a letter dated November 26, 1980 from R. H. Vollmer (NRR) to R. C. Youngdahl (EPRI), the Office of Nuclear Reactor Regulation (NRR) provided comments and requested additional information regarding EPRI's " Proposed Program Plan for the Performance Testing of PWR Safety and Relief Valves", Revision 1, dated July 1, 1980.
In that letter, we requested that the PWR Owners make
" provision for expeditious transmittal of test results from the PWR Owners to the NRC as individual valve tests are completed" so that we could continuously monitor the progress of the test program. The mechanism agreed to for regular transmittal of results is the EPRI Weekly Report. The report is usually issued on Friday and includes a summary of tests conducted at the various test facilities for the week from the previous Monday through the date of the report.
The utilities with assistance from the NSSS vendors have the primary responsibility for evaluating the safety significance of a given test result for their specific plant.
They are responsible under the regulations to advise NRC if information obtained from the test program reveals an un-reviewed safety question for their plant. NRR with assistance from the Office of Nuclear Regulatory Research and its consultant, EG&G Idaho, Inc.,
is reviewing and evaluating each reported test result for potential generic safety significance.
The NRC and consultant personnel reviewing the test results are familiar with the basic valve types being tested, a general knowledge of valve ara related pipina installations in PWR plants and a knowledge of the conservatisms used to design PWR Overpressure Protection Systems. Actions to be taken based on a review of test results that fail a test screening criterion range from consideration of relevance and materiality for Board notification to shut down of plants.
An example of a tast result with obvious safety significance would be failure of a safety valve to open during a given test sequence. As stated in SECY-81-401, dated August 17, 1981 although some test screening criteria have not been met, the testing to date has not uncovered problems with safety or relief valves which are considered significant to the safety of operating plants. This same conclusion is applicable to the McGuire Units.
As applicable to McGuire and as indicated in the previous Board notifications of September 2, 1981 and August 11, 1981 the CCI PORV failed to meet certain initial screening criteria.
The following summarizes the results of the EPRI testing of tha CCI PORV and provides a preliminary plant specific evaluation of the significance of the test results where the PORV failed to meet a test screening criterion.
All tests on the CCI PORV have been completed. The CCI PORV is an air operated valve; that is, in its normal mode of operation air is supplied to the valve operator to both open and close the valve.
The purpose of the backup closure spring is to close the valve should the air supply to the operator be terminated for some reason while the valve is open.
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i Tests performed on the valve included steam tests, water tests and steam to I
water transition tests at nominal reactor operating pressures and temperatures t
i or slightly higher. Additionally water tests were performed at lower pressures
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and temperatures commensurate with those that the valve could be exposed to t
i during reactor startup and shutdown when the valve is used to provided." low i
temperature" overpressure protection for the reactor during those modes of plant operation. Most tests were performed utilizing air to open and close t
the valve and also with the same test sequence repeated with air supply
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to the valve operator terminated when the valve was open to test the capability l
of the backup closure spring to close the valves, f
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l For most tests the CCI valve passed all test screening criteria. The only j
tests where all screening criteria were not met involved tests at 650' F, 2500 psia water and 680* F, 2750 psia steam.
In these tests the valve was in the open position. The air supply to the valve operator was terminated in order to test the closure capability of the backup closure spring. For the j
650' F water test, the valve took as long as 40 sec. to close after the air I
supply was terminated and on the 2750 psia steam test it took 3 sec. to close. The screening criterion specifically violated for these tests was t
failure to close on demand.
Based on a preliminary plant specific evaluation, we conclude that the i
observed delay in valve closure is not of safety significance to operation of McGuire Units 1 and 2 for the following reasons:
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We have completed a safety review of the failure of the CCI PORV to close on i
demand. This postulated failure mode does not have an unacceptable safety r
impact on McGuire because:
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(a) For heatup and overpressurization scenarios, PORV discharge j
through an assumed failed open PORV in the short term mitigates 7
j rather than aggravates event consequences.
l (b) For cooldown and depressurization scenarios analyses show that 4
ECCS actuation would mitigate the consequences of the stuck open PORV(s). This is confirmed by WCAP-9600 analyses, including stuck l
open PORV analyses in which the calculations show that no core un-j covery would occur for the delay in closing of the PORV.
j We have also completed a safety evaluation of the impact of the failure of the CCI PORV to open on demand. The failure of the CCI PORV to open on i
i demand for the screening test in which the CCI PORV tested indicated delays in closure for the 650*F water test and for the 2750 psia steam test would not occur at McGuire because:
(a) During the EPRI screening tests the valves opened upon demand as designed and this failure mode was not observed.
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(b) McGuire safety analysis do not take credit for PORV relieving ccpability, except at low temperature and pressure (less than or equal to 300* F and 400 psig) conditions. The tests verify PORV operability at these lower temperature conditions. Thus, the CCI l
1 PORV is not used as a part of the safety system to serve a safety function at the temperature and pressures indicated in the screening tests of 650' F for the water test and 2750 psia for the steam test.
In summary, the results of the EPRI tests for the CCI PORVs used at McGuire do not indicate unacceptable safety impact and, therefore, are not of safety significance to operation of the McGuire facility. The only failure mode (delayed closure) identified by the preliminary screening tests has been considered by analyses based on enveloping assumptions during previous reviews of McGuire facility.
It is not of safety significance to operation of the McGuire facility.
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December 31,1981 MEMORANDUM FOR: Robert L. Tedesco, Assistant Director for Licensing Division of Licensing FROM:
Darrell G. Eisenhut, Director Division of Licensing
SUBJECT:
BOARD NOTIFICATION FOR McGUIRE 1 & 2 EPRI PORV TESTS I have reviewed your letter of December 29, 1981, and consider it appropriate that the Appeal Board be notified.
Please transmit this information according to the procedures outlined in Office Letter No.19 Revision 1, dated December 9,1980, as Board Noti fication No. 81-57.
7 l f,kA Darrell 6. Eisenhut, Director Division of Licensing l
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DECEMBER 2 S 1981 l
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l MEMORANDUM FOR:
Darrell G. Eisenhut, Director
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Division of Licensing l
FROM:
Robert L. Tedesco, Assistant Director j
for Licensing Division of Licensing i
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SUBJECT:
BOARD NOTIFICATION ON McGUIRE i
Attached herewith is Board Notification on McGuire Nuclear Station, Units 1 and 2 regarding EPRI Test Data on Control Components International i
j (CCI) Power Operated Relief Valves (PORV) for your approval.
N%V Robert L. Tedesco, Assistant Director for Licensing Division of Licensing 1
Enclosure:
l Board Notification I
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Board Notification 81-57 f
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