PLA-6584, Proposed One Time Relief Request to Extend the Test Frequency for Main Steam Safety Relief Valves for Third 10-Year Interval In-Service Testing Program Plan, PLA-6584

Proposed One Time Relief Request to Extend the Test Frequency for Main Steam Safety Relief Valves for Third 10-Year Interval In-Service Testing Program Plan, PLA-6584

ML093350530
Person / Time
Site:	Susquehanna
Issue date:	11/20/2009
From:	Rausch T Susquehanna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-6584
Download: ML093350530 (15)

Text

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Timothy S. Rausch PPL Susquehanna, LLC Sr. Vice President & Chief Nuclear Officer 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3445 Fax 570.542.1504 0%

tsrausch@pplweb.com 020mY3 pp,*4%

U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station OPI-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED ONE TIME RELIEF REQUEST TO EXTEND THE TEST FREQUENCY FOR MAIN STEAM SAFETY RELIEF VALVES FOR THIRD 10-YEAR INTERVAL IN-SERVICE TESTING PROGRAM PLAN FOR SUSQUEHANNA SES UNIT 1 Docket No. 50-387 PLA-6584 Pursuant to 10CFR50.55a(a)(3)(ii) PPL Susquehanna, LLC (PPL) requests NRC approval of Relief Request 07 to the Susquehanna SES Unit 1 In-Service Testing Program Plan.

This Relief Request is an alternative for already approved Relief Request 02. Relief Request 07 would extend the test interval for certain Main Steam Safety Relief Valves (SRVs) beyond 6 years for two SRVs on a one-time basis to allow the testing to be performed during the next refueling outage, which is scheduled to begin in March 2010.

The basis for the request is that compliance with the previously authorized alternative (Relief Request 02) would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

PPL requests approval of this proposed relief request as soon as possible.

In addition a relief request similar to this relief request will be submitted for Susquehanna SES Unit 2. The test interval for the Unit 2 SRVs does not end until the summer of 2010.

Should you have any questions, please contact Michael H. Crowthers at (610) 774-7766.

Sincerely, Ac,(1u

Document Control Desk PLA-6584 - Revision 0 to Relief Request RR-07 Copy: NRC Region I Mr. P. W. Finney, NRC Resident Inspector Mr. R. R. Janati, DEP/BRP Mr. F. W. Jaxheimer, NRC Sr. Resident Inspector Mr. J. S. Kim, NRC Project Manager Mr. B. K. Vaidya, NRC Project Manager

ATTACHMENT 1 TO PLA-6584 REVISION 0 TO RELIEF REQUEST RR-07

Attachment 1 to PLA-6584 Page 1 of 12 RELIEF REQUEST RR-07 Relief in accordance with 10CFR50.55a(a)(3)(ii)

Hardship or Unusual Difficulty without Compensating Increase in Level of Quality or Safety ASME Code Component(s) Affected Serial Number/ Class Category Label Component ID N63790-00-0083/ 1 C MAIN STEAM SRV PSV141FO13A N63790-00-0026/ 1 C MAIN STEAM SRV PSV141FO13C I I I _I These valves are Main Steam Safety/Relief Valves. They provide overpressure protection for the reactor coolant pressure boundary to prevent failure of the reactor vessel pressure boundary that could result in unacceptable radioactive release and exposure to plant personnel. Neither of these two valves is associated with the Automatic Depressurization System (ADS).

2. Applicable Code Requirement PPL Susquehanna, LLC (PPL) Relief Request RR-02, authorized by Reference 1, provides an alternative to ASME OM Code 1998 Edition through OMb-2000 Addenda, paragraph 1-1330, "Test Frequencies, Class 1 Pressure Relief Valves." The alternative requires that Class 1 pressure relief valves be tested at least once every three refueling cycles. It also requires a minimum of 20% of the valves from each valve group to be tested within any 24-month interval. This 20 % shall consist of valves that have not been tested during the current three-cycle interval, if they exist. The test interval for any individual valve shall not exceed three refueling cycles.

3. Basis for Relief OM Code-1998, Appendix I, 1-1300, "Inservice Testing," states the inservice testing shall commence when the valves are required to be operable to fulfill their required function(s). Paragraph 1-1330(a), Test Frequencies, Class 1 Pressure Relief Valves," states that Class 1 pressure relief valves shall be tested at least once every 5 years, starting with initial electric power generation. The alternative to Paragraph 1-1330(a), in PPL's Relief Request RR02, requires that the test interval for any individual Class 1 pressure relief valve shall not exceed three refueling cycles. The required testing ensures that the Main Steam SRVs will open at the pressures assumed in the safety analysis. These valves are located on the main steam lines between the reactor vessel and the inboard main steam isolation valves within the drywell.

Pursuant to 10 CFR 50.55a(a)(3)(ii), PPL requests a one-time relief from (modification to) the requirements of the approved alternative described in Relief Request RR02 for two (2) of the sixteen (16) Main Steam SRVs. Relief is requested

Attachment 1 to PLA-6584 Page 2 of 12 until completion of the spring 2010 refueling outage scheduled to begin in March 2010.

During a review of the industry operating experience, a discrepancy was identified relative to compliance with the 10 CFR 50.55a Relief Request RR02 maximum test interval for an individual SRV of three refueling cycles. The ASME OM Code interpretation (01-18) indicated that implementation of the test interval should be based upon a "test-to-test" duration. The historical method has been to use an "installation-to-test" duration and to ensure that all installed Main Steam SRVs would not exceed the three refueling cycle duration (assuming a 24-month period for each of the refueling cycles). However, utilizing the "test-to-test" interpretation, the three-refueling-cycle interval has expired (assuming a 24 month period for the refueling cycle) for two currently installed Main Steam SRVs. For these two SRVs (see Table 1, valve serial numbers N63790-00-0033, and N63790-00-0024), the failure to complete the testing within the specified frequency has been addressed in accordance with the provisions of Technical Specification (TS) Surveillance Requirement (SR) 3.0.3.

This SR allows compliance with the requirement to declare the limiting condition for operation (LCO) for the SRVs (LCO 3.4.3) not met to be delayed, from the time of discovery, up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or up to the limit of the specified frequency, whichever is greater. For a delay period greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a risk evaluation must be performed and the risk impact managed in accordance with 10 CFR 50.65(a)(4). PPL has performed a risk evaluation and determined that delaying the next test for these two SRVs until the spring 2010 refueling outage was well below the acceptability threshold of IE-06 for incremental conditional core damage probability (ICCDP).

Thus, it is permissible to delay completion of the testing for these two SRVs until the spring 2010 refueling outage.

In addition to the two SRVs discussed above, the three-refueling-cycle interval will expire for two additional Main Steam SRVs (Serial Numbers N63790-00-0083 and N63790-00-0026) prior to the next scheduled refueling outage in spring 2010. These two SRVs are also listed in Table 1. The provisions of TS SR 3.0.3 cannot be applied to these two SRVs since the surveillance interval has not yet been exceeded. The spring 2010 refueling outage is the earliest opportunity to address the discrepancy without requiring Susquehanna SES Unit 1 to enter a forced shutdown to perform these SRV tests.

The basis for this request is that compliance with the requirements in Relief Request RR 02 would result in a hardship without a compensating increase in the level of quality or safety. Technical Specification (TS) 3.4.3 requires that if one or more required SRVs are inoperable, actions must be taken to shut down the reactor.

Susquehanna SES is equipped with sixteen (16) SRVs, of which 14 are required.

Without approval of this relief request, two (2) SRVs will need to be declared inoperable approximately six months prior to the start of the 2010 refueling outage (when they are scheduled to be replaced) for failure to comply with TS SR 3.4.3.1.

This would necessitate a forced shutdown of the unit for testing and replacement of the SRVs if another SRV should become inoperable.

The Main Steam SRVs are located inside the drywell in a high radiation area. The additional dose for the removal, testing, and re-installation of an SRV, including

Attachment 1 to PLA-6584 Page 3 of 12 scaffolding erection/removal and insulation removal/re-installation, would be incurred. If Susquehanna Unit 1 were shutdown before the spring 2010 refueling outage to perform SRV testing, an additional six SRVs would need to be tested during the refueling outage to meet the requirement of Relief Request 02. Thus, additional radiation exposure would be realized if the proposed alternative is not authorized.

Based on the above discussion, and consistent with the guidance in NUREG-1482, Revision 1, Section 2.5, authorization of this one-time request will avoid undue hardship in the form of an unnecessary plant shutdown per TS 3.4.3 should an additional SRV fail and will avoid the additional dose incurred for the replacement and testing of the SRVs.

4. Proposed Alternative and Basis for Use:

For the two Main Steam SRVs impacted, PPL Susquehanna, LLC (PPL) proposes to extend the maximum test interval by varying amounts beyond the specified three refueling cycles (listed in Table 1) to allow testing to be performed during the spring 2010 refueling outage. During the spring 2010 refueling outage, PPL will remove and test all four impacted Main Steam SRVs. The removed valves will be replaced with recently tested valves.

Additionally, as required by the Code, if the as-found set-pressure of any SRV is found to be > 3% above the nameplate set-pressure, two additional SRVs from the same valve group will be tested. If the as-found set-pressure of any of these additional SRVs is found to be > 3% above the nameplate set-pressure, then all remaining SRVs of that same valve group shall be tested.

The basis for this request is as follows:

A review of the setpoint testing results for the time period from initial operation of both Unit 1 and Unit 2 to the present, which comprises 284 data points, shows that the average setpoint change is -0.79%. This slight deviation is well within the requirement specified in TS SR 3.4.3.1 that the as-left setpoint be within plus or minus 1% of the nameplate, and well within the as-found Code requirement of plus or minus 3%. The number of as-found setpoints greater than 1% above the nameplate set pressure was 34. Ten (10) were greater than 2% above the nameplate. Two (2) were greater than the Code tolerance of +3% for the as-found setpoint test, requiring testing of additional SRVs.

The testing data indicates that setpoint history has been good. Twenty (20) valves experienced as-found test results greater than 3% below the nameplate set pressure.

No additional testing, as a result of these as-found tests was required. The time additional testing was required (as-found setpoint greater than +3%) was in 1990 and 1991. The SRV as-found set pressure test data for the last 10 years is summarized in Table 2. Data on the twenty-two (22) Main Steam SRV as-found setpoint test failures identified above is summarized in Attachment 1 to this relief request.

A 24-month fuel cycle has been implemented at Susquehanna SES Unit 1. Each refueling outage, PPL removes and tests six of the sixteen Main Steam SRVs so that all valves are removed and are tested every three refueling outages. Subsequent to

Attachment 1 to PLA-6584 Page 4 of 12 completion of as-found testing, each SRV in the removed complement is disassembled to perform an inspection and maintenance activities, including disc and seat inspection for evidence of degradation such as leakage or misalignment. Any SRV that failed the as-found set pressure test is inspected to determine the cause.

All adverse conditions are corrected, the disc and seats are lapped, and the valve is reassembled. Each SRV is then recertified for service through inspection and testing consistent with ASME OM Code requirements, including set pressure, seat tightness, stroke time and disc lift verifications, solenoid coil pick up/drop out, and air actuator integrity tests.

After recertification testing, the SRVs are stored in controlled areas at the recertification vendor facility and at Susquehanna SES.

The SRV as-found set pressure test data in Table 2 demonstrates that the current maintenance practices outlined above have been effective, and that pre-installation SRV storage has had no significant impact on SRV test results. Only one as-found setpoint test failure has been experienced during the time period encompassed by the data in Table 2. Note that testing performed on SRVs removed during these refueling outages utilized nitrogen, with a correlated set pressure. The data in Table 2 also illustrates that SRVs that have exceeded 6 years between tests have still demonstrated acceptable as-found setpoint test results.

Based on the above cited valve performance history, SRV maintenance practices and the controlled storage environment for the stored SRVs, there is continued assurance of valve operational readiness, as required by ASME OM Code-1998,Appendix I, paragraph 1-1330(a) and Relief Request 02, even given the requested one-time extension of the test interval as outlined in this request. Therefore, PPL has concluded that compliance with the ASME OM Code requirements would result in a hardship or unusual difficulty (in the form of a potential unnecessary plant shutdown per TS 3.4.3 and the additional dose incurred to replace and test the SRVs) without a compensating increase in the level of quality or safety.

5. Duration of Proposed Alternative:

This proposed alternative is requested until the completion of Susquehanna Unit 1 spring 2010 refueling outage, which is currently scheduled to begin in March 2010.

6. Precedents:

Similar relief requests have been approved for other plants as listed below:

Letter from H. Chemoff (USNRC) to C. Pardee (Exelon), "Peach Bottom Atomic Power Station, Units 2 and 3 - Requests for Relief Associated with the Fourth Inservice Testing Interval (TAC Nos. MD7461 and MD7462),"

dated September 3, 2008 (Relief Request Number 01A-VRR-1).

Attachment 1 to PLA-6584 Page 5 of 12

• Letter from R. Gibbs (USNRC) to C. Crane (Exelon), "Dresden Nuclear Power Station, Unit 2 - Request for Relief from ASME OM Code 5-Year Test Interval Requirements (TAC No. MD5959)," dated September 20, 2007 (Relief Request Number RV-02B).

• Letter from N Salgado (USNRC) to S. Belcher (NMPNS), "Nine Mile Point Nuclear Station, Unit 2 - request for Alternative No. MSS-VR-02 main Steam Safety Relief Valve Test Interval Extension (TAC No. ME2130)"

dated September 23, 2009.

7.

References:

1. Letter from R. Laufer (USNRC) to B. L. Shriver (PPL), "Susquehanna Steam Electric Station, Unit 1 and 2 - Third 10 Year Internal Inservice Testing (IST)

Program Plans (TAC Nos. MC3382, MC3383, MC 3384, MC3385, MC3386, MC3387, MC3388, MC3389, MC4421, MC4422)," dated March 10, 2005.

Attachment 1 to.PLA-6584 Page 6 of 12 Table 1: Currently Installed Main Steam SRVs in Susauehanna SES Unit 1 Date MSRV Design "As Left" "As Left" Safety Safety Safety MSRV Actuation Actuation Actuation Installation Installed Valve Setpoint Setpoint Setpoint Position Serial Number (psig) (psig) Last Tested A N63790-00-0083 1175 1181 11/21/03 B N63790-00-0032 1205 1204 8/27/04 C N63790-00-0026 1195 1198 11/22/03 D N63790-00-0128 1175 1183 9/13/07 E N63790-00-0033 1195 1197 11/17/03 F N63790-00-0024 1205 1199 11/19/03 G N63790-00-0129 1205 1200 9/17/07 H N63790-00-0029 1195 1200 8/24/04 J N63790-00-0133 1195 1196 9/21/07 K N63790-00-0093 1205 1210 9/10/05 L N63790-00-0034 1195 1195 9/9/05 M N63790-00-0096 1205 1206 9/11/05 N N63790-00-0132 1195 1191 1/19/06 P N63790-00-0130 1205 1213 9/20/07 R N63790-00-0095 1205 1202 9/7/05 S N63790-00-0112 1205 1208 9/14/07

Attachment 1 to PLA-6584 Page 7 of 12 Table 2: Main Steam SRV As-Found Test results for the Last 10 Years Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0019 3/30/1999 1195 1202 7 0.59 3/24/2002 1195 1185 -10 -0.84 4/22/2009 1195 1155 -40 -3.35 N63790-00-0020 3/25/2002 1205 1178 -27 -2.24 4/22/2009 1205 1165 -40 -3.32 N63790-00-0021 4/6/2001 1195 1200 5 0.42 3/21/2008 1195 1177 -18 -1.51 N63790-00-0022 4/1/1999 1205 1197 -8 -0.66 3/24/2002 1205 1199 -6 -0.50 4/29/2009 1205 1215 10 0.83 N63790-00-0023 3/30/2003 1205 1185 -20 -1.66 3/22/2008 1205 1207 2 0.17 N63790-00-0024 3/28/2003 1205 1196 -9 -0.75 N63790-00-0025 3/30/2003 1205 1169 -36 -2.99 3/21/2008 1205 1137 -68 -5.64 N63790-00-0026 3/31/2003 1195 1174 -21 -1.76 N63790-00-0027 3/24/2002 1195 1162 -33 -2.76 4/22/2009 1195 1204 9 0.75 N63790-00-0028 4/6/2001 1195 1169 -26 -2.18 3/16/2006 1195 1190 -5 -0.42 N63790-00-0029 4/1/1999 1205 1232 27 2.24 3/26/2004 1195 1188 -7 -0.59 N63790-00-0030 4/13/2000 1195 1186 -9 -0.75 3/16/2007 1195 1190 -5 -0.42 N63790-00-0031 3/31/2003 1195 1180 -15 -1.26 3/17/2006 1195 1166 -29 -2.43

Attachment 1 to PLA-6584 Page 8 of 12 Table 2: Main Steam SRV As-Found Test results for the Last 10 Years Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0032 4/6/1999 1205 1184 -21 -1.74 3/25/2004 1205 1176 -29 -2.41 N63790-00-0033 3/31/2003 1195 1190 -5 -0.42 N63790-00-0034 3/11/2005 .1195 1188 -7 -0.59 N63790-00-0081 4/6/2001 1205, 1190 -15 -1.24 3/15/2006 1195 1154 -41 -3.43 N63790-00-0082 3/31/2003 1205 1200 -5 -0.41 3/21/2008 1205 1159 -46 -3.82 N63790-00-0083 3/28/2003 1175 1161 -14 -1.19 N63790-00-0084 3/28/2004 1195 1184 -11 -0.92 N63790-00-0085 4/14/2000 1175 1143 -32 -2.72 3/9/2005 1175 1195 20 1.70 4/23/2009 1175 1123 -52 -4.42 N63790-00-0086 3/29/1999 1195 1166 -29 -2.43 3/28/2004 1175 1191 16 1.36 N63790-00-0087 4/5/2001 1195 1202 7 0.59 3/17/2006 1205 1191 -14 -1.16 N63790-00-0088 4/7/2001 1205 1185 -20 -1.66 3/22/2008 1205 1205 0 0.00 N63790-00-0089 4/7/2001 1205 1185 -20 -1.66 3/16/2006 1205 1210 5 0.41 N63790-00-0090 3/27/2004 1205 1195 -10 -0.83 N63790-00-0091 3/29/2004 1205 1193 -12 -1.00 4/23/2009 1205 1187 -18 -1.49

Attachment 1 to PLA-6584 Page 9 of 12 Table 2: Main Steam SRV As-Found Test results for the Last 10 Years Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0092 3/31/1999 1195 1179 -16 -1.34 3/30/2004 1195 1200 5 0.42 N63790-00-0093 4/14/2000 1205 1191 -14 -1.16 3/10/2005 1205 1154 -51 -4.23 N63790-00-0094 3/30/1999 1205 1224 19 1.58 3/26/2004 1205 1174 -31 -2.57 N63790-00-0095 4/12/2000 1205 1230 25 2.07 3/11/2005 1205 1199 -6 -0.50 N63790-00-0096 4/13/2000 1205 1204 -1 -0.08 3/9/2005 1205 1194 -11 -0.91 N63790-00-0112 3/26/2002 1205 1220 15 1.24 3/15/2007 1205 1209 4 0.33 N63790-00-0113 4/6/2001 1175 1193 18 1.53 3/21/2008 1175 1164 -11 -0.94 N63790-00-0128 3/23/2002 1175 1193 18 1.53 3/15/2007 1175 1184 9 0.77 N63790-00-0129 4/12/2000 1205 1192 -13 -1.08 3/16/2007 1205 1199 -6 -0.50 N63790-00-0130 3/29/1999 1205 1208 3 0.25 3/24/2002 1205 1184 -21 -1.74 3/15/2007 1205 1145 -60 -4.98 N63790-00-0131 4/4/2001 1205 1219 14 1.16 3/15/2006 1205 1215 10 0.83 N63790-00-0132 4/12/2000 1195 1154 -41 -3.43 3/10/2005 1195 1134 -61 -5.10 N63790-00-0133 3/24/2002 1195 1208 13 1.09 3/14/2007 1195 1190 -5 -0.42

Attachment 1 to PLA-6584 Page 10 of 12 : Summary of As-Found Setpoint Failures Since Initial Operation The data for the twenty-two (22) failed Main Steam SRV as-found setpoint tests (i.e., the Code tolerance of plus or minus 3% was exceeded) is summarized below:

Twenty (20) SRV as-found setpoint tests failed on the low side (setpoint less than the

-3% tolerance). The following summarizes the test'data for these SRVs.

Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0019 8/21/1985 1195 1158 -37 -3.10 4/22/2009 1195 1155 -40 -3.35 N63790-00-0020 4/22/2009 1205 1165 -40 -3.32 N63790-00-0021 9/21/1996 1195 1159 -36 -3.01 N63790-00-0022 10/13/1987 1175 1136 -39 -3.32 N63790-00-0024 4/5/1995 1175 1133 -42 -3.57 N63790-00-0025 3/21/2008 1205 1137 -68 -5.64 N63790-00-0030 10/12/1987 1175 1139 -36 -3.06 N63790-00-0081 3/15/2006 1195 1154 -41 -3.43 N63790-00-0082 3/21/2008 1205 1159 -46 -3.82 N63790-00-0085 3/31/1992 1175 1109 -66 -5.62 4/23/2009 1175 1123 -52 -4.42 N63790-00-0089 1/22/1993 1185 1147 -38 -3.21 N63790-00-0090 3/31/1992 1185 1143 -42 -3.54 N63790-00-0091 9/10/1986 1195 1155 -40 -3.35 N63790-00-0093 3/10/2005 1205 1154 -51 -4.23 N63790-00-0113 9/10/1987 1146 1094 -52 -4.54 N63790-00-0130 3/15/2007 1205 1145 -60 -4.98

Attachment 1 to PLA-6584 Page 11 of 12 Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0132 4/12/2000 1195 1154 -41 -3.43 3/10/2005 1195 1134 -61 -5.10 The cause of these failures was determined to be setpoint drift.

• Two (2) SRV as-found setpoint tests failed on the high side (setpoint greater than the

+3% tolerance). The following summarizes the test data for these SRVs.

Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0094 6/18/1991 1205 1244 39 3.24 N63790-00-0130 12/14/1990 1185 1235 50 4.22

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No high side as-found setpoint test failures have occurred since flexi discs have been installed in the SRVs at Susquehanna SES.

Attachment 1 to PLA-6584 Page 12 of 12 NOTE: The two SRVs that are the subject of this relief request have never failed the Code as-found test. The as-found test results for these SRVs are shown in the table below.

Set Pressure Test Deviation Serial Number Date Tested (psig) (psig) (psig)  % Deviation N63790-00-0026 4/28/1985 1146 1117 -29 -2.53 2/26/1988 1146 1154 8 0.70 10/5/1989 1146 1156 10 0.87 6/17/1991 1146 1149 3 0.26 4/10/1995 1146 1170 24 2.09 4/29/1998 1205 .1196 -9 -0.75 3/31/2003 1195 1174 -21 -1.76 N63790-00-0083 9/10/1987 1175 1157 -18 -1.53 10/6/1990 1175 1156 -19 -1.62 8/18/1992 1175 1145 -30 -2.55 4/15/1994 1175 1150 -25 -2.13 9/23/1996 1175 1177 2 0.17 3/28/2003 1175 1161 -14 -1.19

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