ML20045A525
| ML20045A525 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 06/07/1993 |
| From: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NSD930736, NUDOCS 9306110029 | |
| Download: ML20045A525 (17) | |
Text
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e, gm ,,., , GENERAL OFFICE gem P.O. DOX 499, COLUMBUS, NEBRASKA 6BJ02-0499
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QQNebraska Public Power District _ ,
NSD930736 June 7, 1993 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen:
Subject:
Exemption Requests - LLRT of Containment Isolation Valves in Reverse Direction Co( per Nuclear Station NRC Docket No. 50-298, License No. DPR-46 10 CFR 50, Appendix J ,Section III.C establishes the leakage testing requirements for Type C tests on individual primary reactor containment penetrations. This regulation requires, in part, that "... pressure shall be applied in the same direction as that when the valve 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...". Recently, the Nebraska Public Power District (District) has re-evaluated its method for performing this testing as a result of data acquired during the 1993 refueling outage at Cooper Nuclear Station. As a result, ten valves were identified where the current local leak rate test (LLRT) method of applying pressure in the direction opposite to the accident direction, may not yield equivalent or more conservative results, as required by the above regulation. The current configurations of these valves does not allow testing to be performed in the accident direction. On the basis of the information contained in the attachments to this letter, the District hereby requests schedular exemptions from the above identified Appendix J requirements for the ten valves identified. The District requests that these schedular exemptions remain effective until modifications can be made, to allow for Type C testing in the accident direction prior to startup from the next scheduled refueling outage, or subsequent analyses demonstrate that there is no need for the individual schedular exemption (s).
10 CFR 50.12(a) provides the Nuclear Regulatory Commission (NRC) a means of granting exemptions to the requirements of 10 CFR 50 if "special circumstances" are present and the exemptions, " authorized by law, will not present an undue risk to the public health and safety, and are consistent with the common defense and security." On the basis of the information provided herein, the District concludes that "special circumstances" exist which j ustify the individual schedular exemptions for the subject valves under the standards of 10 CFR 50.12.
Attachment 1 to this letter identifies those special circumstances that are present and explains the District's continuing evaluations. Attachment 2 contains the ten individual schedular exemption requests. Attachment 3 contains test results from the 1991 integrated leak rate test (ILRT), along with LLRT data from the subject valves in question, and a comparison of data which demonstrates i that a considerable margin exists to account for potential nonconservatism resulting from testing in the reverse direction, y l
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, U.S. Nuclear Regulatory Commission June 7, 1993 Page 2' of 4 As demonstrated in the attached information, the requested exemptions will not present an undue risk to public health and safety since no significant increase in the risk associated with containment leakage will result from the granting of the exemptions.
.The need for these exemption requests was only recently identified when new information became available concerning the leakage performance of certain types of valves installed at CNS. This new information did not support the District's previous determination that reverse direction testing of certain valves produced equivalent or more conservative results than testing in the accident direction.
Because the information was identified while the plant was in its present refueling outage, sufficient time is not available for the District to properly evaluate the adequacy of the reverse testing methodology, develop a suitable design, and procure material to implement the necessary modifications prior to the scheduled startup from the refueling outage. For this reason, the District is requesting schedular exemptions for the ten valves discussed in the attachments.
The exemptions would provide only temporary relief (one operating cycle) from the applicable regulation. The District has made good-faith efforts in complying-with the regulation through the 'immediate inspection, . document review, calculation, or testing of other valve configurations suspected (through new information provided from the vendors) of not being in compliance with the above requirement of Appendix J. The commitments made in each individual exemption request will effectively modify the valve configurations to allow testing which conforms to the requirements of Appendix J, if subsequent evaluations demonstrate such action is necessary. To perform the modifications for the subject valves during the current refueling outage would represent an undue barden to the District without a commensurate improvement in safety.
In summary, the District has concluded that schedular exemptions for those valves discussed in the attachment are warranted under the standards of 10 CFR 50.12.
Continued improvements made during previous outages and those ongoing during the current refueling outage represent the District's prudent steps to improve containment integrity testing and demonstrate the District's go d-faith efforts to satisfy the requirements of Appendix J. It shculd also be noted that the District has committed to modifying the subject penetretions to achieve full conformance with Appendix J prior to startup from the next refueling outage, if such modifications are shown to be necessary by evaluations currently in progress. With respect to the schedule for the review of this exemption request, the District respectfully requests approval of this request prior to June 21, 1993, which is the projected end date of the current (1993) refueling outage.
The individual schedular exemption requests are requested to remain in effect until required modifications can be completed prior to startup from the next refueling outage, or subsequent analyses demonstrate that there is no need for the' individual schedular exemption (s).
Sincerely, C-~
G Horn N 6 ear Power Group Manager GRH/GRS/dnm Attachments N
U.S.~ Nucioar Regulatory Commission ' '
Juns :7, 1993 Page:3'of 4-1 cc: NRC. Regional Office Region IV-
' Arlington, TX NRC Resident Inspector Cooper Nuclear Station G
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~ June 7, 1993 Page 4"of 4 STATE OF NEBRASKA)
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PIATTE COUNTY )
C. R. Horn, being first duly sworn, deposes and says that he is an authorized representative of the Nebraska Public Power District, a public corporation and-political subdivision of the State of Nebraska; that he is duly authorized to
. submit this request on behalf of Nebraska Public Power District; and that.the-statemenps contained herein are true to the best of his knowledge and belief.
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G. R. Horn ik
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Subscyibed in my presence and sworn to before me this day of dt t nc , , 1993.
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NOTARY PUBLIC MMIM mLG0FF Ilrtuus,95 Ass.RWII 2
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. Attech~.snt 1 Page 1 of 4
- COOPER NUCLEAR STATION e NRC DOCKET No. 50-298 OPERATING LICENSE DPR-46 APPENDIX J EXEMPTION REQUESTS LLRT OF CONTAINMENT ISOLATION VALVES IN THE REVERSE DIRECTION
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Exemotion Reauest Appendix J ,Section III. C. 1 states, in part:
Type C tests shall be performed by local pressurization. The pressure i
shall be applied in the same' direction as that when the valve would:be required to perform its safety function, unless it can be determined that y the results from the tests for a pressure applied in a different direction H will provide equivalent or more conservative results.
In accordance.with the requirements of 10 CFR 50.12, the Nebraska Public Power District (District) requests ten schedular exemptions from the requirements of 10 CFR 50, Appendix J ,Section III .C.1. These schedular exemptions, if granted, need to be effective until modifications can be performed to allow testing which brings the subject valves / penetrations into full conformance with Appendix J prior to startup from the next scheduled refueling outage, or subsequent analyses demonstrate that there is no need for the individual schedular exemption (s).
Discussion The District is applying for schedular exemptions for each of the following valves at CNS: PC-MOV-1304MV, PC-MOV-1306MV, RCIC-MOV-M015, RHR-MOV-M031A, RHR-MOV-M031B, RHR-MOV-M021A, RHR-MOV-M021B, RHR MOV-M016A, RHR-MOV-M016B, and PC-MOV-305MV. PC-MOV-305MV, PC-MOV-1304MV, and PC-MOV-1306MV are solid wedge gate valves. The others are flexible -wedge gate valves. For their containment isolation function, these valves are required to isolate flow away ~ from the primary containment utilizing the disc seating surface on the' opposite side from -
which the primary containment pressure would be applied (outboard seating surface). In order to adequately test this outboard seating surface . in the reverse direction, the valve stem thrust must be sufficient to seat this side of the disc against the test pressure. Unless the seating force provided by the stem thrust is significantly greater than the force from the test pressure applied in the reverse direction, the measured leakage may be through the seating surface on the opposite (inboard) side of the disc. Contrary to the requirements of Appendix J, the test results from reverse direction testing of these valves-may not provide equivalent or more conservative results.
However, by comparing leakage data (in the accident direction) of similar valves to the- valves in question, along with calculating the ratio of seating force
'(comparisons made with similar valves if values are not known) to accident pressure and evaluating past ILRT and LLRT results, the District has a high level of confidence that reverse pressure testing for the valves in question does not yield significantly different data from similar valves that have been tested in the accident direction. Therefore, the intent of 10 CFR 50, Appendix J, and the CNS Technical Specifications leakage restrictions, are continuing to be met.
c .Attachx2nt 1 Page 2 of 4 i
Please be advised that the calculations pertaining to the subject schedular i
requests are preliminary in that they are still undergoing final District ;
i engineering review. These calculations, however, were completed and provided under the contractor's District-approved nuclear quality assurance yrogram, and have received preliminary engineering review by the District, 10 CFR 50.12 Analysis The District concludes that the individual exemptions from the requirements of 10 CFR 50 Appendix J, are justified pursuant to 10 CFR 50.12, Sections (a)(1),
(a)(2)(ii), (a)(2)(iii), (a)(2)(v), and (a)(2)(vi) in that:
- These exemptions will'not present an undue risk to the public health and safety.
The proposed exemptions do not change, modify, or restrict existing plant safety limits, safety settings, or operations. The exemptions do not impact the design basis of containment or significantly modify its response 'during a design basis accident. The l i
penetrations have been satisfactorily tested in the correct I direction during the most recent ILRT.
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- Application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule.
The LLRT Type C test information as.nciated with the - reverse pressure testing of the subject individual penetrations demonstrates I generally equivalent results to what is required by Appendix J., j There is sufficient test data, calculation,_ and documented engineering judgment to conclude that any differences in leakage -)
between testing of these valves in the accidei direction versus.
reverse direction testing are not significant, and would in any case, result in leakage rates within Appendix J limits. Thus, the-underlying purpose of the Appendix J, which is to limit leakage from primary reactor containment through systems and components penetrating primary reactor containment so that it does not exceed allowable leakage rate values, as specified - in .the technical specifications or associated bases, has been met.
1
+- Compliance would result in costs that are significantly in excess of those contemplated when the regulation was adopted.
g Until recently, the District believed that it was in full compliance with the requirements cf Appendix J,Section III.C.1, based on the ;
information available at the time. The District has recently become aware of new information regarding the subject valves which
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i indicates that reverse direction testing may not, in ' all cases, yield the equivalent or conservative values required by Appendix J.,
l- Because this problem has only been recently discovered, it would be l' difficult to design, procure, and modify the subject penetrations l
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Attachment 1 Pegs 3 of 4 1 in a timely manner. The discussions contained in the. individual-schedular exemption requests demonstrate the amount of modification !
necessary to bring the subject valve / penetration testing into i conformance, if calculations in progress demonstrate that !
modification will be required. Immediate corrective action would result in undue costs without a commensurate improvement in safety.
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. The exemptions would provide only temporary relief from the applicable .l regulation and licensee or applicant has made good-faith efforts to comply )
with the regulation. ';
The District has identified, due to recently available information, some primary containment isolation valves where reverse direction f LLRT testing may have resulted in less conservative results than I testing in the accident direction. The District, however, took a conservative approach through additional testing, inspection, calculations, and document searches to ensure that these valves yielded equivalent or conservative results, when tested in the i reverse direction. The individual exemption requests, attached, ')
represent only those valves / penetrations for which there was either 1 a necessity to modify (to allow for testing in the accident 1 direction) in order to bring them into full compliance with Appendix i J, or insufficient data was currently available to state, without question, that the tests in the reverse direction are equal to, or-more conservative than, tests in the accident direction. The District plans to modify these penetrations / valves (where calculated data and motor operator data reveals that modification is necessary) prior to the end of the next scheduled refueling outage. The District believes that the actions taken, along with actions to be .j taken, represent good faith' efforts to comply with the regulation. ';
+ There is present any other material circumstances not considered when the regulation was adopted for which it would be in the public interest to j grant an exemption, j At the time 10 CFR 50 Appendix J was originally drafted (1971), this l regulation allowed testing in the reverse direction for any valve !
with a nominal diameter of less than 12 inches. When this regulation was finally promulgated (1973), construction _of CNS was essentially complete. The District performed several modifications
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in order to meet this regulation. Since that time, the District has l maintained, and is continually updating, the documentation bases and-testing program to ensure primary reactor containment penetration i testing meets Appendix J requirements. For valves where testing in -i the accident direction is not possible in the present configuration, the' District had performed calculations and evaluations to demonstrate that such testing yields results equal to, or more ;
conservative than would be achieved by accident direction testing.
It has only been recently determined,.through the availability of new testing information, that the valves identified in the specific ;
exemption requests (Attachment 2) either lack sufficient thrust 1
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, Attachment 1 Page 4 of 4 data, or have thrust data v'aich indicates that - testing in the reverse direction may not f ield equivalent or more conservative results.
i Environmental Consideration The requested schedular exemptions temporarily change a requirement with respect to installation or use of a facility component located within'the i
restricted area as defined.in 10 CFR Part 20. As demonstrated in the -
attachments, the District has determined that the requested schedular exemptions involve no significant increase in the. amounts, and no-significant change in the types, of any effluents that may _ be released offsite, that they involve no significant hazards consideration,= and that there is no significant increase in individual.or cumulative occupational radiation exposure. Accordingly, the proposed schedular exemptions. meet the eligibility criteria for categorical exclusion set forth in .10 CFR Section 51.22(c)(9) . Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the schedular exemptions.
In summary, the District has concluded that the ten schedular exemptions for=
those penetrations, discussed above, are warranted under-the' standards of 10 CFR-50.12. Continued improvements made during previous outages and those ongoing during the current refueling outage represent the District's prudent steps to improve containment integrity testing and demonstrate the District's good-faith efforts to satisfy the requirements of Appendix J.
With respect to the schedule for the review of this exemption request, the District respectfully requests approval of this request prior to June 21, 1993.
which is the current projected end date of the current (1993) refueling outage.
The ten schedular exemptions are requested to remain in effect until the next scheduled refueling outage.
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Attachment 2 !
Page 1 of 8 COOPER NUCLEAR STATION 10 CFR 50 APPENDIX J. SECTION III.C.1 INDIVIDUAL REQUESTS FOR SCHEDULAR EXEMPTIONS i ggneral Discussion - Determination of Fagfors in Suonort of Schedular Exemptions The District is applying for schedular exemptions from the requirements of 10 CFR 50 Appendix J, Section III.C.1 for the following valves: PC-MOV-1304MV, PC-MOV-1306MV, RCIC MOV-M015, RHR-MOV-M031A, RHR-MOV-M031B, RHR-MOV-M021A, RHR-MOV- ,
M021B, RHR-MOV-M016A, RER-MOV-M016B, and PC-MOV-305MV. In order to support the '
individual schedular exemption. requests, the District has identified factors based on the comparison of leakage datt (in the accident direction) of similar valves, calculations of seating force ratios to accident pressure, and evaluation of past ILRT and LLRT results. For valves that do not have available thrust test data, seating force to accident pressure ratios are based on comparisons to similar valves which have such thrust data available.
In general, the District does not expect local leak rates (in the accident direction at 58 psig) through the valves in question to be significantly different than that experienced by reverse pressure testing. This is demonstrated by data collected on two valves, similar to the valves in question, where both reverse direction and accident direction data is available. For valve CS-MOV-M05B (3" flex wedge gate), reverse direction testing resulted in a flow of 0.69 standard cubic feet per hour (sefh), while testing in the accident direction results in a flow of 0.43 scfh. This results in a net difference of
(+) 0.26 scfh. For valve RW-A0V-A082 (3" flex wedge gate), reverse direction testing resulted in a flow of 0.09 scfh, while testing in the accident direction yielded 0.45 scfh, which results in a net difference of (-) 0.36 scfh. In both cases, the accident direction leakage is well below the Appendix J limits specified for these penetrations, and reverse direction testing has provided a good indication of the leak tightness of these valves.
Attachment 3 provides the LLRT (reverse direction) results for the ten valves in question. Total leakage, in the reverse direction, measured in 1993 for these valves was 15.21 scfh. For the 1991 outage, the minimum path as left leakage for all type B and C tests, totaled 99.11 scfh (including the subject ten penetrations). The ILRT for 1991 (which pressurized the valves in question in the accident direction) yielded results of 102.5 scfh. Given the startup limit of 189 scfh and 316 scfh (total allowable limit) per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, the local leak rate for the valves in question for startup or operation, would have to be approximately (total for the ten valves) 90 sem and 216 scfh, respectively to approach the Technical Specification limits. Given the two examples provided above, and the 1991 ILRT results, the District believes that the ten valves in question will satisfactorily perform their containment isolation function and that considerable margin exists to account for additional leakage, if any, that may take place from the valves being pressurized in the accident direction.
For each of the ten valves in question, the District has estimated the closing thrust force to accident pressure ratio and the seating force to accident pressure ratio. These estimates are either based on valve-specific test data, or test data based on similar valves where such data, for the valve in question, is not yet available. The seating force to test pressure ratio is estimated by taking the measured thrust, divided by 2 to derive a value per wedge, then dividing the resultant number by the pressure force exerted on the disk (at test pressure, 63.8 psig). The ratio of stem thrust to pressure force estimate is approximately double the seating force to pressure force ratio for disks that are generally normal (90 degrees) to the pressure force exerted. As a general rule, ,
the higher these ratios are, the less likely leakage from the accident direction will differ from the reverse testing direction; thus, leak geometry is dominated by the seating and stem force and not by test direction.
The District has also included a list of potential modifications, if necessary, which could be implemented in order to bring the valve testing requirements into compliance with Appendix J. Although this list is not all inclusive, it does provide those options which are considered to be the most practical.
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Attachmsnt 2 Page 2 of 8 Schedular Exemption Reauest for Penetration X-10. RCIC-MOV-M015
- 1) Descrintion a 3", 900 lb, Flex Wedge Gate Valve
+ Drawings B5700 - 2041 (Flow)
A3950 - 768-3
- 2) Potential Modifications Reauired
+ Installation of an isolation valve between Nozzle N-3C and RCIC-V-79 and RCIC-V-78 (RCIC Steam Line Vent Root and Shutoff).
- Installation of a larger motor operator in order to obtain the required thrust.
- 3) Factors in Sunnort of Schedular Exemption
- Calculations show that the ratio of seating force to test pressure force is 5.9 to 1. The ratio.of stem thrust to test .
pressure is 11.9 to 1. These margins are sufficient to ensure that leak geometry is dominated by seating force and not test direction.
Considering both the accident direction and reverse direction testing results of similar valves (see discussion regarding-CS-MOV-M05B and RW-A0V-A082 on Page 1 of this attachment), no appreciable difference should be expected in leakage between testing in the accident direction and testing in the reverse direction.
- 4) Conclusion The District requests a schedular exemption for one cycle from the accident-direction testing requirement of Appendix'J for RCIC-MOV-M015, penetration X-10. Prior to the end of the next scheduled refueling outage, the District plans to implement modifications in order to bring the valve testing into full compliance with Section III.C.1 of the appendix, or to provide a subsequent acceptable evaluation to show that the subject testing-requirements are met.
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. Attachment 2 Page 3 of 8 Schedular Exemotion Recuest for Penetrations X-39A and X-39B. RHR-MOV-M031A &
RHR-MOV-M031B (Two Exemption Recuests Combinedl
- 1) Descrintion
+ 10", 300 lb, Flex Wedge Cate Valve
- Drawings .B5700 - 2040 (Flow)
A3950 - 829-3 Rev. NO3
- 2) Potential Modifications Reauired ;
+
The installation of 10" manual isolation valves between the drywell spray header and both RHR-MOV-M031A and M031B.
The installation of test connections between the manual isolation valves proposed above -and both RHR-MOV-M031A and '
M031B. ;
- Installation of a larger motor operator in order to obtain the required thrust.
- 3) Factors in Suncort of Schedular Exemotion
- Limitorque data is available for both RHR-MOV-M031A and 31B.
For RHR-MOV-M031A, the ratio of seating force to test pressure force is 1.28 to 1 and the rario of stem thrust to test pressure force is 2.55 to 1. For RHR-MOV-M031B, the ratio of seating force to test pressure force is 2.0 to 1 and the ratio of stem thrust to test pressure force is 4.0 to 1. These margins are sufficient to ensure that leak geometry -is dominated by seating force and not test direction for both valves in question.
+ For the RHR valves in question, the RHR system can be considered as a closed loop outside containment such that, under accident conditions, any leakage past these valves will leak into associated RHR piping and not into the .' reactor building atmosphere.
- 4) Conclusion The District. requests schedular exemptions for one cycle from the:
accident-direction testing requirement of Appendix J for both RHR- ;
MOV-M031A and M031B, penetrations X-39A and X-39B, respectively. 4 Prior to the end of the next scheduled refueling outage, the District plans to implement modifications in order to bring the valve testing into full compliance with Section III.C.1 of the appendix, or to provide a subsequent acceptable evaluation to show that the subject testing requirements are met. j i
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Attachment 2 I' age 4 of 8 Schedular Exemption Recuest for Penetrations X-210A and X-210B. RHR-MOV-M021A
& RHR-MOV-M021B (Two Exemption Recuests Combined)
- 1) Descriotion-
+ 4", 300 lb, Flex Wedge Gate Valve
- Drawings B5700 - 2040 (Flow)
A3950 - 833-3 Rev. NO3
- 2) Potential Modifications Recuired
+ The installation of 4" manual isolation valves between the Torus and both RHR-MOV-M021A and M021B.
+
The installation of test connections between the manual-isolation valves proposed above and both RHR-MOV-M021A and i M0218.
- Installation of a larger motor operator in order to obtain the-required thrust.
- 3) Factors in Suovort of Schedular Exemption
+ Stem thrust data is not yet available for the motor operators (RHR-MO-M021A and RHR-MO-M021B) to RHR-MOV-M021A and M0218.
Once the District completes MOV testing to determine "as--
found" stem thrust, the thrust calculations will be performed.
This information will be available prior to the conclusion of the next scheduled refueling outage, in sufficient time to allow for modification, if necessary.
+ To account for the lack of available stem thrust data for RHR-MOV-M021A and 21B, the stem thrust data for M016A and 16B (same valve type) has been used as a comparison to the valves in question. When averaged, the data associated for M016A and .
16B yields a ratio of seating force to test pressure force of 3.56 to 1, and the ratio of stem thrust to test pressure force of 7.1 to 1. These margins are sufficient to ensure that leak geometry is dominated by seating force and not test direction.
For the FOUt valves in question, the RIUl' system can be considered as a closed loop outside containment such that, under accident conditions, any leakage past these valves will leak into associated RHR piping and not into the - reactor building atmosphere.
+ Considering both the accident direction and reverse direction testing results of similar valves (see discussion regardiag CS-MOV-MOSB and RW-A0V-A082 on Page 1 of this attachment), no appreciable difference should be expected in leakage between~
testing in the accident direction and testing in the reverse direction.
- 4) Conclusion The District requests schedular exemptions for one cycle from the accident-direction testing requirement of Appendix J for both RHR- -
MOV-M021A and M021B, penetrations X-210A and X-210B, respectively.
The District will provide an acceptable evaluation to show either that these valves meet the testing requirements of Section III.C.1 of Appendix J, or the District will implement modifications prior to the end of the next scheduled refueling outage in order to bring the valve testing into full compliance with Section III.C.1 of the appendix. .
j Attachrtsnt 2 Page.5 of 8 Schedular Exemntion Reauest for Penetrations X-210A and X-210B. RHR-MOV-M016A
& RHR-MOV-M016B (Two Exemntion Reauests Combined')
- 1) Description
+ 4", 300 lb, Flex Wedge Gate Valve
+
Drawings B5700 - 2040 (Flow)
A3950 - 833-3 Rev. NO3
- 2) Potential Modifications Reauired
+
The installation of 4" manual isolation valves between the Torus and both RHR-MOV-M016A and M016B.
+
The installation of test conn'ections between the manual-isolation valves proposed above ano both RHR-MOV-M016A and M016B.
Installation of a larger motor operator in order to obtain the required thrust.
- 3) Factors in Suonort of Schedular Exemptip.D a Limitorque data is available for both RHR-MOV-M016A and 16B.
For RHR-MOV-M016A, the ratio of seating force to test pressure L.
force is 3.27 to 1 and the ratio of stem thrust to test-pressure force is 6.55 to 1. For RHR-MOV-M016B, the ratio of seating force-to test pressure force is 3.86 to 1 and the ratio of stem thrust to test pressure force is 7.7 to 1.
These margins are sufficient to ensure that leak geometry is dominated by seating force and.not test direction for both valves in question.
+
For the RHR valves in question, the RHR system can be considered as a closed loop outside containment such that, under accident conditions, any leakage past these valves will-leak into associated RRR piping and not into the reactor building atmosphere.
Considering both the accident direction and reverse direction testing results of similar valves (see discussion regarding CS-MOV-M05B and RW-A0V-A082 on Page 1 of this attachment), no appreciable difference should be expected in leakage between testing in the accident direction and testing in the reverse direction.
- 4) Conclusion The District requests schedular exemptions for one cycle from the accident-direction testing requirement of Appendix J for both RHR-MOV-M016A and MO16B, penetrations X-210A and X-210B, respectively.
Prior to the end of the next scheduled refueling outage, the District plans to implement modifications in order to. bring the valve testing into full compliance with Section III.C.1 of the appendix, or to provide a subsequent acceptable evaluation to show that the subject testing requirements are met.
a AttachmsntL2 Page 6,of 8 U Schedular Exemption Reauest for Penetration X-205. PC-MOV-1304MV'
- 1) Descriotion
- 1", 150 lb, Solid Wedge Cate Valve Drawings B5700 - 2084 (Flow)
A3950 - 2509-3A Rev. A
- 2) Potential Modifications Reauired The installation of a test connection between PC MOV-1304MV and PC-V-484, the manual = isolation valve.
Installation of a -larger motor operator in order to obtain the, required thrust.
- 3) Factors in Support of Schedular Exemotion Stem thrust data-is not-yet available for the motor operator; (PC-MO-1304MV) to PC-MOV-1304MV. Once the' District completes; MOV testing to determine "as-found" stem thrust, the thrust calculations will be performed, This ' informaticu will be available - prior - to the conclusion of ' the nexc' scheduled refueling- outage, in sufficient time 'to allow for-modification, if necessary.
+
Stem thrust data for valves similar to PC-MOV-1304MV. is.known at this time. The stem thrust values for these similar valves avera;e out to 3288 Ibs. Therefore - the ratio of averaged seatiag force to the pressure force is 24 to-1 and the ratio of averaged closing thrust to test, pressure force is 49 to 1.
.These margins are sufficient.to ensure that leak geometry is dominated by-seating force and not-test direction.
- Considering both the accident direction ~and reverse direction testing- results' of similar vaives, (see discussion regarding CS-MOV-M05B and RW A0V-A082 on Page 1 of this attachment), no appreciable difference should be expected in leakage between-testing in the accident direction and testing in the reverse-
, direction.-
- 4) Conclusion-The District requests a schedular exemption for one cycle from .
the accident-direction testing requirement of Appendix J.for PC-MOV-1304MV, penetration X-205. -The District will provide an acceptable evaluation- to show either that this valve meets -
the testing requirements of Section III,C.1; of Appendix J, or -
the District will implement modifications prior;to the end of the next scheduled refueling outage ; in order to bring- the -
valve testing into full compliance with Section III.C.1 of the '
appendix.~
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< Attachmsnt 2--
4 Page 7 of 8 Schedular Exemption Reauest for Penetration X-25. PC-MOV-1306MV
- 1) Descriotion a 1", 150 lb, Solid Wedge Cate Valve Drawings B5700 - 2084 (Flow)
A3950 - 2509-3A Rev. A
- 2) Potential Modifications Recuired-
+
The installation of a test connection between PC-MOV-1306MV and PC-V-482, the manual isolation valve.
- Installation of a larger motor operator in order to obtain the required thrust.
- 3) Factors in Suncort of Schedular Exemotion
+
Stem thrust data is not yet available for the motor operator (PC-MO-1306MV) to PC-MOV-1306MV. Once the District completes MOV testing to determine "as-found" stem thrust, the thrust calculations will be performed. This information will be available prior to the conclusion of the next scheduled refueling outage, in sufficient time to. allow for modification, if necessary.
+ Stem thrust data for valves similar to PC-MOV-1306MV is known at this time. The stem thrust values for these similar valves average out to 3288 lbs. Therefore the ratio of averaged seating force to the pressure force is 24 to 1 and the ratio of averaged closing thrust to test pressure force is 49 to 1.
These margins are sufficient to ensure that leak geometry is dominated by seating force and not test direction,
+
Considering both the accident direction and reverse direction testing results of similar valves (see discussion regarding CS-MOV-M05B and RW- A0V-A082 on Page 1 of this attachment), no appreciable difference'should be expected in leakage between testing in the accident direction and testing in the reverse direction.
- 4) Conclusion The District requests a schedular exemption for one cycle from the accident-direction testing requirement of Appendix J for PC-MOV-1306MV, penetration X-25. The District will provide an acceptable evaluation to show either that this valve meets the testing requirements of Section III.C.1 of Appendix J, or the District will implement modifications prior to the end of the next scheduled refueling outage in order to bring the valve testing into full compliance with Section III.C.1 of the appendix.
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--. Attachmsnt 2 i Page 8 of 8 l Schedular Exemotion Reauest for Penetration X-220. PC-MOV-305MV
- 1) fiscription l 2", 150 lb, Solid Wedge Cate Valve
+
Drawings B5700 - 2022-(Flow)
A3950 - 2866-3
- 2) Potential Modifications Recuired
+ Installation of a 2" manual isolation valve and a test connection between PC-MOV-305MV and the 2" piping upstream of PC-MOV-305MV.
+
Installation of a larger motor operator in order to obtain the required thrust.
- 3) Factors in Suonort of Schedular Exemotion
+
Calculations show that the ratio of seating force to test-pressure force is 8.75 to 1. The ratio of' stem thrust to test pressure is 7.5 to 1. These margins are sufficient to ensure that leak geometry is dominated by seating force and not test direction.
+
Calculation of the thrust. limit value of 5179 lbs includes a 922 lb packing thrust margin based on actual MOV measured data for closing thrust. When compared to the actual measured closing thrust of 4688 lbs, it is apparent, at this time, there is adequate seating force. The packing. thrust margins allow for operational changes over the upcoming cycla.
Considering both the accident direction and reverse direction testing results of similar valves (see discussion'regarding-CS-MOV-M05B and RW-A0V-A082 on Page 1 of this attachment), no-appreciable difference should be expected in leakage between testing in the accident direction and testing in the reverse direction.
- 4) Conclusion The District requests schedular exemptions for one cycle from the accident-direction testing requirement of Appendix-J for PC-MOV-305MV, penetration X-220. Prior to the end of the next scheduled refueling outage, the District plans to implement modifications in order to bring the valve testing into full compliance with Section III.C.1 of the appendix, or to provide a subsequent acceptable evaluation to show that the subject testing requirements are met. '
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Attachment 3 Page 1 of 1 RESULTS OF 1991 ILRT, RECENT RESULTS OF LIRT ON VALVES REQUESTED FOR EXEMPTION, AND POSTUIATED AFFECT OF SUBJECT VALVES ON TOTAL CONTAINMENT LEAKAGE RATE During the 1991 integrated leak rate test (ILRT), the ' 95 percent (%) upper confidence limit (UCL) leak rate plus type B and C adjustments was 0.2060 weight (wt) % per day using total time figures. This results in:
'0.00206 vm ' ' 89802.39* lbs' - 185 lbb_a day , . day-K
- Represents weight of containment atmosphere at '
58 psig.
' 185 J1g ' 13. 3 asf 1 day' - 102.5 scfh day 1b ,, 24 hr.
-which is the accident direction leakage of the penetrations and the containment structure itself when pressurized to design basis pressure (58 psig). This can be compared to the minimum path as-left leakage total of all type B and C tests, '
which totaled 99.11 scfh from the 1991 outage. Even though the valves, listed below (requested for exemptions), were tested in the reversed-direction, these results are consistent with ' the ILRT leakage results even when the total penetration leakage for a11' penetrations associated with these valves is added !
to the minimum path total. Total 1993 as-found leak rate from type C-tests was --,
as follows: ,
X-39A (through both MO-26A and MO-31A) - 2.93 scfh X-39B (through both MO-26B and MO-31B) - 0.375 scfh X-210A (through MO-21A) - 0.0 - scfh X-210A (through MO-16A, 10CV, 12CV) - 0.0 sefh X-210B (through MO-21B)'- 3.85 scfh i X-210B (through MO-16B, 11CV, 13CV) - 0,69 scfh-X-10 (through RCIC-M015 & M016).- 3.38 scfh X-205 (through both PC-1303MV &-1304MV) - 0.07 scfh
- X-25 (through both PC-1305MV & 1306MV) - 0.015 scfh X-220 (through PC 230MV, PC-245AV, PC-305MV, & PC-1308MV) - 3.9 sefh '
Total: 15.21 scfh Adding the 15.21 scfh value to the total B and C penetration leakage results in-114.32 scfh total leakage, .approximately one third of the La (316 sefh) that allowed by CNS Technical Specifications. Also, it is approximately 60% of the startup limit of 0.6 La (189 sefh). Therefore,- there is considerable margin for potential degradation of any of these containment penetrations. ,
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