ML20199M162

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Proposed Alternatives PRR-01, PRR-02, PRR-03, and PRR-04 to the Requirements of the ASME OM Code (Epids L-2020-LLR-0007 to L-2020-LLR-0010)
ML20199M162
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 07/21/2020
From: Jennifer Dixon-Herrity
Plant Licensing Branch IV
To: Gerry Powell
South Texas
Galvin D
References
EPID L-2020-LLR-0007, EPID L-2020-LLR-0008, EPID L-2020-LLR-0009, EPID L-2020-LLR-0010
Download: ML20199M162 (13)


Text

July 21, 2020 Mr. G. T. Powell President and Chief Executive Officer STP Nuclear Operating Company P.O. Box 289 Wadsworth, TX 77483

SUBJECT:

SOUTH TEXAS PROJECT, UNITS 1 AND 2 - PROPOSED ALTERNATIVES PRR-01, PRR-02, PRR-03, AND PRR-04 TO THE REQUIREMENTS OF THE ASME OM CODE (EPIDS L-2020-LLR-0007 TO L-2020-LLR-0010)

Dear Mr. Powell:

By letters dated January 22, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML20022A318, ML20022A319, ML20022A320, and ML20022A321),

as supplemented by letter dated May 18, 2020 (ADAMS Accession No. ML20139A216), STP Nuclear Operating Company (STPNOC, the licensee) submitted requests to the U.S. Nuclear Regulatory Commission (NRC) for the use of alternatives to certain American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), requirements at South Texas Project (STP) Units 1 and 2.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) paragraph 50.55a(z)(1), the licensee requested to use the proposed alternatives in Alternative Requests PRR-01, PRR-02, PRR-03, and PRR-04, regarding pump inservice testing on the basis that the proposed alternatives would provide an acceptable level of quality or safety.

By letter dated May 7, 2020 (ADAMS Accession No. ML20128J902), STPNOC withdrew proposed Alternative Request PRR-02. As noted in the May 7, 2020, letter, the incorporation by reference on April 15, 2020 (85 FR 14736; March 16, 2020), of Regulatory Guide 1.192, Operation and Maintenance Code Case Acceptability, ASME OM Code, Revision 3, into the NRCs regulations made proposed Alternative Request PRR-02 unnecessary. The NRC acknowledges the request to withdraw proposed Alternative Request PRR-02.

The NRC staff has reviewed the subject requests and concludes, as set forth in the enclosed safety evaluation, that STPNOC has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(1) and demonstrated that the proposed alternatives provide an acceptable level of quality and safety. Therefore, the NRC staff authorizes the use of the Alternative Requests PRR-01, PRR-03 and PRR-04 for STP Units 1 and 2 for the fourth 10-year inservice testing interval, which is scheduled to begin on September 25, 2020, and end on September 24, 2030.

The NRC staff noted that the licensees submittals stated that the end date for the fourth 10-year inservice testing interval is September 25, 2030, which is a typographical error. The correct end date should be September 24, 2030.

G. Powell All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests remain applicable.

If you have any questions, please contact the Project Manager, Dennis Galvin at 301-415-6256 or via e-mail at Dennis.Galvin@nrc.gov.

Sincerely, Jennifer L. Digitally signed by Jennifer L. Dixon-Herrity Dixon-Herrity Date: 2020.07.21 10:31:28 -04'00' Jennifer L. Dixon-Herrity, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499

Enclosure:

Safety Evaluation cc: Listserv

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION PROPOSED ALTERNATIVES REQUESTS PRR-01, PRR-03, AND PRR-04 REGARDING THE FOURTH 10-YEAR INTERVAL INSERVICE TESTING PROGRAM STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT, UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499

1.0 INTRODUCTION

By letters dated January 22, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML20022A318, ML20022A320, and ML20022A321), as supplemented by letter dated May 18, 2020 (ADAMS Accession No. ML20139A216), STP Nuclear Operating Company (STPNOC, the licensee) submitted requests to the U.S. Nuclear Regulatory Commission (NRC) for the use of alternatives to certain requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), at South Texas Project (STP) Units 1 and 2.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR)

Paragraph 50.55a(z)(1), the licensee requested to use the proposed alternatives in Alternative Requests PRR-01, PRR-03, and PRR-04, regarding pump inservice testing (IST), on the basis that the proposed alternatives would provide an acceptable level of quality or safety.

2.0 REGULATORY EVALUATION

Paragraph 50.55a(f)(4) of 10 CFR, Inservice testing standards requirement for operating plants, states, in part, that:

Throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the inservice test requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in [10 CFR 50.55a(f)(2) and (3)] and that are incorporated by reference in [10 CFR 50.55a(a)(1)(iv)], to the extent practical within the limitations of design, geometry, and materials of construction of the components.

Enclosure

The regulations in 10 CFR 50.55a(z), Alternatives to codes and standards requirements, state, in part, that alternatives to the requirements of 10 CFR 50.55a(f) may be used, when authorized by the NRC, if the licensee demonstrates (1) the proposed alternatives would provide an acceptable level of quality and safety or (2) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request, and the NRC to authorize, the proposed alternative requested by the licensee.

3.0 TECHNICAL EVALUATION

The STP Units 1 and 2 fourth 10-year IST program interval begins on September 25, 2020, and is scheduled to end on September 24, 2030.1 The applicable ASME OM Code edition for the STP Units 1 and 2 fourth 10-year IST program interval is the 2012 Edition, which is incorporated by reference in 10 CFR 50.55a with conditions.

3.1 Licensees Alternative Request PRR-01 The licensee requested an alternative to the pump testing requirements of the ASME OM Code.

Paragraph ISTB-3400, Frequency of Inservice Tests, states, An inservice test shall be run on each pump as specified in Table ISTB-3400-1.

Table ISTB-3400-1, Inservice Test Frequency, states that, Group A and Group B tests are to be performed quarterly and a comprehensive test is to be performed biennially.

The licensee has requested to use the proposed alternative described below for the pumps listed in Table 1.

Table 1 Pump Description Comprehensive Pump ASME Test (CPT) Flow Rate Code (Gallons per Minute) Class 3S141(2)MPA01 Auxiliary Feedwater Pump 11/21 545 3 3S141(2)MPA02 Auxiliary Feedwater Pump 12/22 545 3 3S141(2)MPA03 Auxiliary Feedwater Pump 13/23 545 3 3S141(2)MPA04 Auxiliary Feedwater Pump 14/24 545 3 3R201(2)NPA1(2)01A Component Cooling Water Pump 12500 3 1A/2A 3R201(2)NPA1(2)01B Component Cooling Water Pump 12500 3 1B/2B 1

The NRC staff noted that the licensees submittal dated January 22, 2020, stated that the end date for the fourth 10-year IST interval is September 25, 2030, which is a typographical error. The correct end date should be September 24, 2030.

Pump Description Comprehensive Pump ASME Test (CPT) Flow Rate Code (Gallons per Minute) Class 3R201(2)NPA1(2)01C Component Cooling Water Pump 12500 3 1C/2C 3V111(2)VPA004 Essential Chilled Water Pump 885 3 11A/21A 3V111(2)VPA005 Essential Chilled Water Pump 885 3 11B/21B 3V111(2)VPA006 Essential Chilled Water Pump 885 3 11C/21C 3R211(2)NPA(2)01A Spent Fuel Pool Cooling Pump 2550 3 1A/2A 3R211(2)NPA(2)01B Spent Fuel Pool Cooling Pump 2550 3 1B/2B

Reason for Request

The ASME OM Code committees have approved Code Case OMN-18, Alternate Testing Requirements for Pumps Tested Quarterly Within +/- 20% of Design Flow. This Code Case has been conditionally approved for use in Regulatory Guide (RG) 1.192, Operation and Maintenance Code Case Acceptability, ASME OM Code, Revision 2, dated March 2017, for the ASME OM Code, 2012 Edition (ADAMS Accession No. ML16321A337).

Code Case OMN-18 allows the Owner to not perform the CPT with the associated acceptance criteria, if the quarterly test is performed at +/- 20 percent of design flow rate and with instrumentation that meets the accuracy requirements of Table ISTB-3510-1, Required Instrument Accuracy, for the comprehensive and preservice tests.

Paragraph ISTB-1400(b) states that it is the Owners responsibility to categorize the pumps in their program. As such, an Owner could categorize a pump that otherwise meets the requirements of Group B, as Group A pump, and test according to the provision of Code Case OMN-18. However, in doing so, additional data (vibration and flow or differential pressure) is obtained quarterly, rather than once every 2 years.

RG 1.192, Revision 2, conditionally approved the use of OMN-18, with the condition that the upper end values of the Group A Test Acceptable Ranges for flow and differential pressure (or discharge pressure) must be 1.06Qr and 1.06Pr (or 1.06Pr), respectively, as applicable to the pump type. The high values of the Required Action Ranges for flow and differential pressure (or discharge pressure) must be >1.06 Qr and > 1.06Pr (or 1.06Pr), respectively, as applicable to the pump type (Qr denotes flow reference value, Pr denotes differential pressure reference value, and Pr denotes discharge pressure reference value).

Proposed Alternative The licensee proposes to use the provisions of Code Case OMN-18 to perform a quarterly Group A test in lieu of performing a biennial CPT and apply the acceptance criteria associated with the Group A test. As an alternative to using the acceptance criteria associated with the

Group A test, the licensee will specify the acceptance criteria associated with the upper limit as 1.06 Qr and 1.06 Pr in lieu of the 1.10 percent of the reference value allowed by Table ISTB-5121-1, Centrifugal Pump Test Acceptance Criteria. This alternative testing is applicable to only those pumps with full flow testing capability. The pressure instrumentation used during the tests shall have an accuracy of at least 0.5 percent.

By letter dated May 18, 2020, the licensee stated that for the pumps listed in Table 1, the reference values that will be used are the CPT flow rates. The reference flows for the essential chilled water pumps will vary slightly from the CPT flow rate due to the variance allowed in paragraph ISTB-5221(b). The reference flows for the spent fuel pool cooling pumps 3R211(2)NPA(2)01A, pumps 1A and 2A, will vary slightly from the CPT flow rate due to the variance allowed in paragraph ISTB-5121(b).

The licensee also stated that CPT testing requirements will be met during the performance of the quarterly tests for the essential cooling water pumps. Therefore, the licensee withdrew the essential cooling water pumps from this alternative request.

NRC Staff Evaluation

The licensee proposes to perform IST for the pumps listed above in Table 1, in accordance with a modified Group A test procedure, and no CPT will be performed. The licensee requested to use ASME Code Case OMN-18 with the conditions listed in Table 2, Conditionally Acceptable OM Code Cases of RG 1.192 Revision 2.

The ASME OM Code requires that for Group A pumps, a Group A test be performed quarterly, and a CPT be performed biennially. The Group A test is performed at the CPT flow rate, if practicable; the pressure instrument accuracy is +/- 2 percent, and the upper limit for the Acceptable Range for flow rate and differential pressure is 110 percent of the reference values.

There is no Alert Range for the Group A test. The CPT is performed at the CPT flow rate, the pressure instrument accuracy is +/- 1/2 percent, and the upper limit of the Acceptable Range for flow rate and differential pressure is 106 percent of the reference values. There is an Alert Range for the CPT.

Code Case OMN-18 is applicable to the 1994 Addenda of the ASME OM Code through the 2006 Addenda. The NRC staff has reviewed the 2012 Edition of the ASME OM Code and has determined that there is no technical reason that the Code Case cannot be used with the 2012 Edition of the ASME OM Code.

The licensee proposed that for Group A pumps, a modified quarterly test be performed quarterly, and the biennial CPT not be performed. The modified Group A test would be performed at the CPT flow rate, with slight variances as described above, and with the more accurate pressure instrumentation that is required for the comprehensive test (+/- 1/2 percent instead of +/- 2 percent). The Acceptable Range for the modified Group A test is also narrower than the Acceptable Range for the Group A test.

The licensee will use a more limiting upper bound of 106 percent of the flow and differential pressure reference values for the Acceptable Range for flow and differential pressure in lieu of 110 percent that is required by the OM Code for Group A tests. Therefore, the pumps noted in Table 1 will be in the Required Action Range if they exceed 106 percent of the Acceptable Range reference values for flow and differential pressure. This is consistent with the condition imposed on the acceptable use of Code Case OMN-18 in RG.1.192.

The NRC staff finds that allowing usage of Code Case OMN-18 provides an acceptable level of quality and safety for the pumps listed in Table 1 because all of the tests will be performed with a more accurate pressure instrumentation and the Acceptable Range for the modified test is narrower than the Acceptable Range for the Group A test. The elimination of the CPT is compensated for by using a more accurate pressure instrumentation with a narrower Acceptable Range for every quarterly test. This will provide better trending of pump performance.

The NRC staff notes that in Section 4 of the licensees submittal for Alternative Request PRR-01, it is stated that Guidelines set forth in Code Case OMN-18 Revision 1, Use of a Pump Curve for Testing, will be followed. There is a typographical error in this sentence, and it should read, Guidelines set forth in Code Case OMN-18, Alternate Testing Requirements for Pumps Tested Quarterly Within +/- 20% of Design Flow will be followed.

The NRC staff also notes that RG 1.192, Revision 3 has been incorporated by reference into 10 CFR 50.55a. Code Case OMN-18 and the NRC conditions in Table 2 of RG 1.192, Revision 3 are identical to the Code Case and conditions in RG 1.192, Revision 2.

3.2 Licensees Alternative Request PRR-03 Table ISTB-3400-1 requires that a Group A pump test be performed quarterly.

The licensee has requested to use the proposed alternative described below for the pumps listed in Table 2.

Table 2 Pump Description ASME Code Class 2R161(2)NPA1(2)01A Residual Heat Removal (RHR) Pump A 2 2R161(2)NPA1(2)01B RHR Pump B 2 2R161(2)NPA1(2)01C RHR Pump C 2

Reason for Request

The licensee has previously stated that STP Units 1 and 2 have three RHR pump trains used only for long-term cooldown events following auxiliary feedwater operations. STP Units 1 and 2 are unique in the design of its RHR system. Whereas other plants have two trains of RHR, STP Units 1 and 2 have three trains of RHR. The RHR system does not serve the low head safety injection function, and is therefore, not critical to the immediate accident mitigation function.

Less emphasis should be placed on the quarterly testing of these pumps at power due to the RHR system negligible impact on core damage frequency and large early release frequency.

The licensee referenced the NRC safety evaluation in Amendment Nos. 59 and 47 for STP, Units 1 and 2, respectively, dated February 17, 1994 (ADAMS Accession No. ML021300134),

for the relief granted for the IWP-3400(a) RHR pump test requirements, allowing a testing frequency extension of these pumps from 3 to 6 months. The licensee also referenced the NRC safety evaluation in a letter dated September 2, 2010 (ADAMS Accession No. ML102150077),

for NRC authorization for the same three RHR pumps test requirements, allowing a testing frequency extension of these pumps from 3 to 6 months for the third 10-year interval of the IST program Proposed Alternative The licensee proposes that a Group A IST will be performed on each RHR pump listed above in Table 2 nominally every 6 months during normal plant operation instead of every 3 months as stated in Table ISTB-3400-1 of the ASME OM Code. This test frequency will be maintained during plant shutdown periods if it can reasonably be accomplished per the requirements of paragraph ISTB-5121, Group A Test Procedure. A CPT per paragraph ISTB-5123, Comprehensive Test Procedure, may be performed in lieu of a Group A test.

STP Units 1 and 2 have three RHR trains used for long-term cooldown events following safety injection system operation. The RHR system does not perform the low-head safety injection function as required at other plants and is therefore not critical to the immediate accident mitigation function.

The licensee stated that the RHR system, including the RHR pumps, continues to be operated as designed with no change in function or performance. The pumps have performed well in the third 10-year IST interval with no unacceptable test results. The risk metrics for the RHR pumps remain consistent with the values used in the original risk analysis. The licensee stated that since the proposed change in the RHR pump surveillance interval represents a negligible change in core damage frequency, the alternative testing frequency for the IST requirements will provide an equivalent level of safety for these pumps.

NRC Staff Evaluation

The licensees analysis mentioned in the February 17, 1994, letter, was reviewed by the NRC and Brookhaven National Laboratory to check the licensees three-train analysis for the percent change in system unavailability and core damage frequency. The results of the review indicated that the licensees proposed change in the RHR pump IST interval represents an insignificant change in system unavailability and no change in core damage frequency. This is documented in the NRC letter dated September 2, 2010.

The NRC staff finds that the proposed alternative provides an acceptable level of quality and safety for the RHR pumps in Table 2 because past analysis has demonstrated that changing the Group A test requirement for these three RHR pumps from 3 months to 6 months results in negligible change in system unavailability and core damage frequency.

The NRC staff notes that similar requests were authorized in the second and third 10-year IST program intervals, and the pumps continue to operate as designed with no change in performance.

3.3 Licensees Alternative Request PRR-04 Paragraph ISTB-3300, Reference Values, states, in part, Reference values shall be obtained as follows: (a) Initial reference values shall be determined from the results of testing meeting the requirements of para. [paragraph] ISTB-3100, Preservice Testing, or from the results of the first inservice test.

Table ISTB-5121-1, provides the values for the Alert Range and Required Action Range for inservice tests.

Table ISTB-5221-1, Vertical Line Shaft Centrifugal Pump Test Acceptance Criteria, provides the values for the Alert Range and Required Action Range for inservice tests.

Table ISTB-5321-1, Positive Displacement Pump (Except Reciprocating) Test Acceptance Criteria, provides the values for the Alert Range and Required Action Range for inservice tests.

Table ISTB-5321-2, Reciprocating Positive Displacement Pump Test Acceptance Criteria, provides the values for the Alert Range and Required Action Range for inservice tests.

The licensee requested to use the proposed alternative described below for the pumps listed in Table 3 and pumps in their IST program that meet the requirements of Code Case OMN-22, Smooth Running Pumps, in the future.

Table 3 Pump Description Unit ASME Code Class 2R171NPA101A Centrifugal Charging Pump 1A 1 2 2R171NPA101B Centrifugal Charging Pump 1B 1 2 2R172NPA201A Centrifugal Charging Pump 2A 2 2 3V111VPA004 Essential Chilled Water Pump 11A 1 3 3V111VPA005 Essential Chilled Water Pump 11B 1 3 3V111VPA006 Essential Chilled Water Pump 11C 1 3 3V112VPA004 Essential Chilled Water Pump 21A 2 3 3V112VPA005 Essential Chilled Water Pump 21B 2 3 3V112VPA006 Essential Chilled Water Pump 21C 2 3 3R281NPA101A Essential Cooling Water Pump 1A 1 3 3R281NPA101B Essential Cooling Water Pump 1B 1 3 3R281NPA101C Essential Cooling Water Pump 1C 1 3 3R282NPA201A Essential Cooling Water Pump 2A 2 3 3R282NPA201B Essential Cooling Water Pump 2B 2 3 3R282NPA201C Essential Cooling Water Pump 2C 2 3 2N121NPA102A Low Head Safety Injection Pump 1A 1 2 2N121NPA102B Low Head Safety Injection Pump 1B 1 2 2N121NPA102C Low Head Safety Injection Pump 1C 1 2 2N122NPA202A Low Head Safety Injection Pump 2A 2 2 2N122NPA202B Low Head Safety Injection Pump 2B 2 2 2N122NPA202C Low Head Safety Injection Pump 2C 2 2 3S141MPA01 Motor Driven Aux Feedwater Pump No.11 1 3 3S142MPA02 Motor Driven Aux Feedwater Pump No.22 2 3

3S142MPA03 Motor Driven Aux Feedwater Pump No.23 2 3 3S141MPA04 Turbine Driven Aux Feedwater Pump No. 14 1 3 2R161NPA101A RHR Pump 1A 1 2 2R161NPA101B RHR Pump 1B 1 2 2R161NPA101C RHR Pump 1C 1 2 2R162NPA201A RHR Pump 2A 2 2 2R162NPA201B RHR Pump 2B 2 2 2R162NPA201C RHR Pump 2C 2 2 3R211NPA101A Spent Fuel Cooling Pump 1A 1 3 3R211NPA101B Spent Fuel Cooling Pump 1B 1 3 3R212NPA201A Spent Fuel Cooling Pump 2A 2 3 3R212NPA201B Spent Fuel Cooling Pump 2B 2 3 Additional pumps may be added to the scope of Code Case OMN-22 based on their future reference value tests.

Reason for Request

In its letter dated January 22, 2020, the licensee states, in part:

The ASME Code committees have approved Code Case OMN-22, Smooth Running Pumps and is scheduled to be published with the 2020 ASME OM Code. This Code Case has not been approved for use in Regulatory Guide 1.192.

Code Case OMN-22 allows for alternative requirements for use with smooth running pumps in lieu of use of vibration values obtained in the reference value tests. For very low reference values, hydraulic noise and instrument accuracy can represent a significant portion of the reading and affect the repeatability of subsequent measurements. A smooth running pump could be subject to unnecessary increased testing if the measured vibration parameter exceeds an acceptable range based on these very low reference values.

Smooth running pumps have a much lower reference value for stable operation and the ranges for acceptable range and higher levels listed in the Alert Range do not allow for adequate vibration monitoring techniques to be applied to smooth running pumps. Guidelines set forth in Code Case OMN-22 allow for a very lower baseline vibration value with a pump vibration velocity of 0.050 in/sec [inches per second] when establishing the vibration reference value, which allows for trending of the pump vibration on a much lower scale than what is currently allowed.

ASME OM Code Case OMN-22, Smooth Running Pumps has not been approved by the NRC and a relief request is required for use of this Code Case.

Proposed Alternative The licensee further states, in part:

STPNOC proposes to utilize the provisions of Code Case OMN-22, Smooth Running Pumps. For those pumps with very low vibration values, the following vibration velocity criteria shall be applied to any vibration test points qualifying for the use of the minimum reference value:

Acceptable Range: 0.125 in/sec Alert Range: > 0.125 in/sec to 0.300 in/sec Required Action Range: > 0.300 in/sec Supplemental Monitoring:

Pumps that will use the minimum reference value for one or more vibration points will be maintained in STPNOCs Predictive Maintenance (PdM) program.

The PdM program will apply predictive monitoring techniques and perform vibration analysis beyond the trending of vibration levels specified in the ASME OM Code to provide early identification of pump performance issues.

At a minimum, STPNOC will perform spectral analysis of measured vibration of the applicable pumps. STPNOC will document the conclusion of the PdM performance analysis on the pump test record prior to the subsequent test with a conclusion of acceptable, degrading but acceptable, or unacceptable. Corrective action will be initiated when an unacceptable trend in performance is identified.

Corrective Action:

If a measured pump vibration parameter falls within the alert range or the required action range specified above, STPNOC will follow the required actions within the edition/addenda of the applicable Code (for example, ISTB-6200 for the 2012 Edition of the ASME OM Code). The alert and required action ranges would be established in accordance with Code Case OMN-22 rather than the requirements of ISTB-3300, ISTB-5100, and ISTB-5200 and the associated tables.

If a PdM Supplemental Monitoring activity identifies a parameter outside the normal operating range or identifies a trend toward an unacceptable degraded state, action will be taken to (1) identify and document the condition in the Corrective Action Program; (2) increase monitoring to establish the rate of change on the monitored parameter; (3) review component-specific information to identify the degradation cause; (4) develop a plan to remove the pump from service to perform maintenance prior to significant performance degradation; and (5) address potential common cause issues applicable to other pumps based on the results of the analysis of the specific pump performance.

NRC Staff Evaluation

The licensee proposes to use ASME OM Code Case OMN-22 for the pumps listed in Table 3, and other pumps in its IST program that meet the requirements of Code Case OMN-22 in the

future. The Code Case has been approved by the ASME OM Standards Committee, with the NRC representative voting in the affirmative. The Code Case has also been approved by the ASME Board of Nuclear Codes and Standards.

ASME Code Case OMN-22 will be included in the proposed Revision 4 of RG 1.192, where it will be listed in the table of Code Cases acceptable for use. There will be no conditions. The Code Case can be used for any pump in a licensees IST program that meets the requirements of the Code Case. RG 1.192, Revision 4, is currently scheduled to be incorporated by reference in 10 CFR 50.55a in the fall of 2021. The Code Case is applicable to the 2012 Edition of the ASME OM Code, which will be the licensees Code of Record for its fourth 10-year IST program interval.

The NRC staff finds that allowing usage of Code Case OMN-22 provides an acceptable level of quality and safety for the pumps listed in Table 3, and any pumps meeting the requirements of Code Case OMN-22 in the future, because this alternative will provide adequate indication of pump performance and the licensees predictive maintenance program will ensure the licensees ability to detect problems involving an unacceptable condition in advance of when the pump performance may reach an unacceptable condition.

4.0 CONCLUSION

As set forth above, the NRC staff has determined that for alternative requests PRR-01, PRR-02 and PRR-04 for STP Units 1 and 2, the proposed alternatives provide an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1) for alternative requests PRR-01, PRR-03 and PRR-04. Therefore, the NRC staff authorizes the use of the alternative requests PRR-01, PRR-03 and PRR-04 for STP Units 1 and 2 for the fourth 10-year IST interval, which is scheduled to begin on September 25, 2020, and end on September 24, 2030.

As the NRC staff previously noted, the licensees submittal stated that the end date for the fourth 10-year IST interval is September 25, 2030, which is a typographical error. The correct end date should be September 24, 2030.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests remain applicable.

Principal Contributors: Yiu Law, NRR Robert Wolfgang, NRR Date: July 21, 2020

ML20199M162 *Via e-mail OFFICE NRR/DORL/LPL4/PM* NRR/DORL/LPL4/LA* NRR/DEX/EMIB/BC* NRR/DORL/LPL4/BC*

NAME DGalvin PBlechman ABuford JDixon-Herrity DATE 07/20/2020 07/20/2020 07/02/2020 07/21/2020