ML19305D566

Revised Request for License Amendment: Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R11

ML19305D566
Person / Time
Site:	Vogtle
Issue date:	11/01/2019
From:	Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation
Shared Package
ML19305D559	List: ML19305D561 ML19305D566 ND-19-1097, Response to Request for Additional Information - LAR-19-013R1
References
ND-19-1097
Download: ML19305D566 (16)

Text

Southern Nuclear Operating Company ND-19-1097 Vogtle Electric Generating Plant (VEGP) Units 3 and 4 Revised Request for License Amendment:

Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

(This Enclosure consists of 16 pages, including this cover page)

ND-19-1097 Elimination of License Condition to Evaluate Pressurlzer Surge Line Stratification (LAR-19-013R1)

Table of Contents

1.

SUMMARY

DESCRIPTION

2.

DETAILED DESCRIPTION 2.1 System Design and Operation 2.2 Current Licensing Basis Requirements 2.3 Reason for the Proposed Change 2.4 Description of the Proposed Change

3.

TECHNICAL EVALUATION 3.1 Pressurlzer Surge Line Analysis and Design 3.2 Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) and ASME Code III Compliance 3.3 Permanent Plant Pressurlzer Surge Line Instrumentation 3.4 First Plant Test Results 3.5 Summary

4.

REGULATORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 No Significant Hazards Consideration Analysis 4.4 Conclusions

5.

ENVIRONMENTAL CONSIDERATION

6.

REFERENCES Page 2 of 16

ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

1.

SUMMARY

DESCRIPTION Pursuant to 10 GFR 52.98(c) and in accordance with 10 CFR 50.90, Southern Nuclear Operating Company (SNC, or the "Licensee") hereby requests an amendment to Combined License (COL)

Nos. NPF-91 and NPF-92 for Vogtle Electric Generating Plant (VEGP) Units 3 and 4, respectively.

Specifically, the requested amendment would eliminate COL condition 2.D.(2)(a)1 which describes a first plant Pressurizer Surge Line Stratification Evaluation and make related revisions to the Updated Final Safety Analysis Report (UFSAR) Tier 2 information. Because this change would modify the COL, this amendment request requires prior Nuclear Regulatory Commission (NRC) approval.

2. DETAILED DESCRIPTION 2.1 System Design and Operation The AP1000 pressurizer surge line is an eighteen inch line that connects the top of the Reactor Coolant System (RCS) hot leg 1 to the bottom of the pressurizer. The surge line is designed to accommodate thermal expansion and movement. As such, it is designed with smooth pipe bends rather than fittings and is designed to slope continuously downward to the hot leg without horizontal segments in order to minimize thermal stratification. The design of the pressurizer vessel accounts for the possibility of thermal stratification in the pressurizer during normal power operation and for the possibility of insurges and outsurges.

The pressurizer surge line layout provides for adequate flexibility to accommodate thermal expansion as well as movement when the line is at full operating temperature. The pressurizer piping and loop arrangement is designed for flexibility with a fixed vessel and a free floating steam generator/reactor coolant pump support system. The reactor coolant loop and surge line piping are designed to leak-before-break (LBB) criteria.

There are three permanently installed, nonsafety-related, strap-on resistance temperature detectors (RTDs) located on the RCS pressurizer surge line. These instruments continuously monitor the pressurizer surge line fluid temperature during plant normal operations in order to detect thermal stratification in the surge line. Two of the RTDs are located on a moderately sloped run approximately midway between the RCS hot leg and the pressurizer. One detector is located on the bottom of the pipe and the other detector on the top. The third detector is located on the pressurizer surge line as close to the pressurizer nozzle as possible. This detector is used to monitor cold insurges to the pressurizer during transient operations.

Temperature indication is provided in the main control room. One low temperature alarm is provided to alert the operator of thermal stratification in the surge line. This alarm is associated with the detector on the bottom of the pipe. During heat up and cooldown operations, a differential temperature alarm indicates significant thermal stratification using the difference between the temperatures measured at the top and bottom of the pipe.

As part of the AP1000 plant conformance to NRC Bulletin 88-11, Pressurizer Surge Line Thermal Stratification, a monitoring program has been implemented for the first API 000 plant (i.e., Sanmen Unit 1) to record temperature distributions and thermal displacements of the surge line piping during hot functional testing and during the first fuel cycle. The first API 000 unit used temporary pressurizer surge line instrumentation, in addition to permanent plant Page 3 of 16

ND-19-1097 Ellmination of License Condition to Evaluate Pressurlzer Surge Line Stratification (LAR-19-013R1) instrumentation, for monitoring the thermal stratification of the pipeline and the displacement of the surge line during hot functional testing and during the plant's first fuel cycle. This information is being used to validate assumptions and design inputs used in surge line fatigue analyses.

2.2 Current Licensing Basis Requirements NRG Bulletin 88-11 was issued after Portland Electric Generating Company observed unexpected movement of the pressurizer surge line of the Trojan plant during inspections performed at each refueling outage since they began monitoring surge line movements in 1982. The investigation concluded that movement of piping was caused by thermal stratification in the line. Thermal stratification may occur in piping when flow rates are low and adequate mixing of hot and cold fluid layers does not occur. Thermal stratification in stagnant or slowly flowing lines can result in thermal fatigue in a pipe. NRC Bulletin 88-11 requested that all operating license and construction permit holders at PWRs establish and implement a program to confirm pressurizer surge line integrity in view of the occurrence of thermal stratification and required addressees to inform the NRC staff of actions taken to resolve this issue.

UFSAR Section 3.9.3.1.2 discusses the API 000 conformance to NRC Bulletin 88-11. Request 2.c) of Bulletin 88-11 requests that applicants "... either monitor the surge line for the effects of thermal stratification beginning with hot functional testing, or obtain data through collective efforts to assess the extent of thermal stratification, thermal striping and piping displacements." The API 000 conformance statement describes the Westinghouse Owners Group program on surge line thermal stratification and surge line data collected from the industry. The API 000 conformance statement also commits to monitoring the surge line during hot functional testing and during the first cycle of the first API 000 plant. It points to the commitment in UFSAR Subsection 3.9.8.5 to perform the monitoring.

COL Section 2.D.(2)(a)1. requires that a "Pressurizer Surge Line Stratification Evaluation (first plant test as identified in UFSAR Section 14.2.9.1.7 item (d))" be performed by SNC. UFSAR Section 14.2.9.1.7 item (d) describes the monitoring program that will be performed and directs readers to USFAR Section 3.9.3. Additionally, there is discussion of the commitment to perform the Pressurizer Surge Line Testing for the first plant only in UFSAR Section 14.2.9.2.22.

2.3 Reason for the Proposed Change Pressurizer surge line monitoring is required at the first API 000 unit, as described in UFSAR Subsections 3.9.3.1.2 and 14.2.9.1.7 item (d). This monitoring does not need to be performed at Vogtle Units 3 and 4. The API 000 plant, as described in the UFSAR, has been designed to limit thermal stratification in the pressurizer surge line in accordance with NRC Bulletin 88-

11. First plant data has been collected and will be used to verify the inputs used in the pressurizer surge line design analysis, which will be included as part of the as-built reconciliation of the reactor coolant system ASME Section III Piping System. The as-built reconciliation includes the evaluation of pipe break dynamic loads, changes in support locations, construction deviations, and completion of the small bore piping analysis. Even though the Sanmen Unit 1 data is sufficient to perform the verification of the API 000 surge line design analysis inputs, the data recorded from the Vogtle Units 3 and 4 permanent plant RTDs can be used to confirm the surge line is operating as expected. Therefore, it is not necessary to collect additional pressurizer surge line data at Vogtle Unit 3 and 4.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1) 2.4 Description of the Proposed Change Pressurizer surge line monitoring is required at the first API 000 unit, as described in UFSAR Subsections 3.9.3.1.2 and 14.2.9.1.7 item (d). The monitoring, as described in the Vogtie 3 and 4 UFSAR Subsections 3.9.3 and 14.2.5, is part of the conformance to Bulletin 88-11.

The requested amendment involves changes to eliminate the performance of the Pressurizer Surge Line Stratification Evaluation first plant test at VEGP Units 3 and 4 by revising UFSAR Subsections 14.2.5, 14.2.9.1.7 and 14.2.9.2.22 and COL condition 2.D.(2)(a)1.

3. TECHNICAL EVALUATION Thermal stratification, cycling and striping are phenomena that have resulted in pipe cracking at nuclear power plants. As a result of these incidents, the United States Nuclear Regulatory Commission has issued several bulletins, including NRC Bulletin 88-08, Thermal Stresses in Piping Connected to Reactor Coolant Systems, and NRC Bulletin 88-11, Pressurizer Surge Line Thermal Stratification.

Thermal stratification may occur in piping when flow rates are low and adequate mixing of hot and cold fluid layers does not occur. Thermal cycling due to stratification may occur because of leaking valves or plant operation. Thermal striping is a cyclic mechanism caused by instabilities in the hot-cold fluid interface in stratified fluid during relatively steady flow conditions. The design of piping and component nozzles in the API 000 design includes provisions to minimize the potential for and the effects of thermal stratification and cycling.

Likewise, piping and component supports have been designed and evaluated for the thermal expansion of the piping resulting from potential stratification modes. The API 000 plant pressurizer surge line design included consideration of the information on thermal cycling and thermal stratification described in NRC Bulletins 79-13,88-08, and 88-11, and other applicable design standards.

The pressurizer surge line is constructed to ASME Code Section III requirements, has leak-before-break capabilities and the functional capability is demonstrated by ITAAC. Additionally, there are three permanently installed nonsafety-related RTDs located on the RCS pressurizer surge line. These instruments monitor the pressurizer surge line fluid temperature to detect thermal stratification in the surge line. Lastly, the first API 000 plant (Sanmen Unit 1) monitored the temperature in the pressurizer surge line using temporary RTDs and displacement sensors, as well as, the three permanent plant RTDs during hot functional testing and the first fuel cycle. The steady state displacement and temperature measurements of the surge line at different plateaus during hot functional testing heat up and cooldown have met acceptance criteria. The data collected at Sanmen Unit 1 is representative of the data that would be collected at Vogtie Units 3 and 4 with first-cycle temporary instrumentation. Because Sanmen Unit 1 and Vogtie 3 and 4 are both using the standard API 000 design for the pressurizer surge line, it is unlikely that additional insight into the temperature stratification phenomena will be gained by collecting more data at Vogtie Unit 3 and 4.

The evaluation of the data from the first operating plant will be included as a part of the as-built reconciliation of the RCS ASME Section III piping system, as described in UFSAR Section 3.9. The data recorded at Sanmen 1 is contained within a test report that will be used to reconcile the Vogtie Units 3 and 4 as-built fatigue and piping stress analyses. The as-built Page 5 of 16

ND-19-1097 Elimination of License Condition to Evaluate Pressurlzer Surge Line Stratification (LAR-19-013R1) analysis package will be used to demonstrate completion of Combined License (COL),

Appendix C, ITAAC 2.1.02.02a (Index No. 13).

COL Appendix C ITAACs acceptance criteria must be met and the ITAAC completed prior to operation. The pressurlzer surge line Is Identified In ITAAC Table 2.1.2-2 and must meet ASME Code Section III requirements. This ITAAC states, "[t]he piping Identified In Table 2.1.2-2 as ASME Code Section III Is designed and constructed In accordance with the ASME Code Section III requirements." The changes to remove the temporary monitoring requirements for the pressurlzer surge line do not Impact the ability of the surge line to meet the ASME Code Section III requirements. Design specifications and design reports for ASME Section III piping are made available for NRC review. Reconciliation of the as-bullt piping (verification of thermal cycling and stratification loading, as described In UFSAR Section 3.9.8.2) Is completed after the construction of the piping systems and prior to fuel load.

Piping functional capability Is not a specific ASME Code requirement but It Is a requirement In the UFSAR (reference: 3.6.3, 3.6.4.1, Table 3.9-11, Appendix 3b, 5.2.1). As such. Information demonstrating that UFSAR functional capability requirements are met Is Included In the ASME Section III As-Bullt Design Reports for safety class piping prepared In accordance with ASME Section III NCA-3550 under the ASME Boiler & Pressure Vessel Code (1998 Edition, 2000 Addenda)Section III requirements. The as-bullt piping systems are subjected to a reconciliation process, which verifies that the as-bullt piping systems are analyzed for functional capability and for compliance with the design specification and ASME Code provisions. Design reconciliation of the as-bullt systems validates that construction completion. Including field changes and any nonconforming condition dispositions. Is consistent with and bounded by the approved design. As required by ASME Code, the As-Bullt Design Report Includes the results of physical Inspection of the piping and reconciliation to the design pipe stress report.

3.1 Pressurlzer Surge Line Analysts and Design The proposed change to remove the requirement to thermally monitor the API 000 pressurlzer surge line during hot functional testing and the first operating cycle does not Impact the ability of the surge line to perform Its safety-related design function, as described In the UFSAR.

UFSAR Section 5.4.3.3 describes how the pressurlzer surge line has been designed and Instrumented to minimize the potential for thermal stratification and how It Is monitored to provide Indication to the operators of the temperatures In the surge line. Three locations are monitored with permanent plant equipment (strap-on RTDs). The change to remove the requirement for temporary Instrumentation does not Impact the permanent plant Instrumentation or the requirement that the temperature In the surge line be monitored by plant operators.

UFSAR Section 3.9.3.1.2 describes how the API 000 plant conforms with NRC Bulletin 88-11, sections 2.a) through 2.d). Conformance with each of the requests In the Bulletin continues to be achieved without performing additional thermal monitoring of the surge line at Vogtle Units 3 and 4. As described below, each of the Bulletin requests are listed, along with the current UFSAR API 000 conformance statement, and an additional discussion of how the request continues to be satisfied.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

NRG Bulletin 88-11 Requirement 2.a):

Before issuance of the low power license, applicants are requested to demonstrate that the pressurizer surge line meets the applicable design codes and other FSAR and regulatory commitments for the licensed life of the plant. This may be accomplished by performing a plant specific or generic bounding analysis. The analysis should Include consideration of thermal stratification and thermal striping to ensure that fatigue and stresses are In compliance with applicable code limits. The analysis and hot functional testing should verify that piping thermal deflections result In no adverse consequences, such as contacting the pipe whip restraints. If analysis or test results show Code noncompllance, conduct of all actions specified below Is requested.

UFSAR AP1 OOP Conformance Statement for Requirement 2.a): Analysis of the AP1000 surge line considers thermal stratification and thermal striping, and demonstrates that the surge line meets applicable code requirements for the licensed life of the plant. Hot functional testing requirements for the AP1000 ensure that piping thermal deflections result in no adverse consequences.

Design Discussion for Requirement 2.a): AP1000 design conformance with this requirement continues to be satisfied. The design and function of the surge line are not impacted by this change. A three-dimensional computational fluid dynamics model of the API 000 pressurizer surge line was performed in order to determine the stratification profiles for the AP1000 pressurizer surge line used in the design analyses. In addition, the AP1000 pressurizer surge line piping stress analysis, including a fatigue analysis, evaluated the pressurizer surge line components according to the Class 1 design analysis requirements of the Section III ASME B&PV Code, 1998 Edition and 2000 Addenda.

NRC Bulletin 88-11 Requirement 2.b):

Applicants are requested to evaluate operational alternatives or piping modifications needed to reduce fatigue and stresses to acceptable levels.

UFSAR AP1000 Conformance Statement for Requirement 2.b):

Analysis of the AP1000 surge line confirmed that stress and fatigue requirements are satisfied, therefore the evaluation of operational alternatives or piping modifications was not required.

Design Discussion for Requirement 2.b):

Removal of the requirement to thermally monitor the AP1000 pressurizer surge line during hot functional testing and the first cycle of operation using temporary monitoring instrumentation does not impact the design of the pressurizer surge line. The AP1000 pressurizer surge line is designed to accommodate thermal expansion. During conditions with the greatest potential for thermal stratification, the pressurizer heaters and spray valves may be operated to maintain a continuous outflow of water to minimize the severity of stratification and the possibility of pressurizer thermal transients resulting from insurges. The permanent strap-on RTDs will continue to perform their design function, monitoring the surge line temperatures and alerting the operators in the event of temperature measurements that may indicate thermal stratification in the pressure surge line.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

NRG Bulletin 88-11 Requirement 2.c):

Applicants are requested to either monitor the surge line for the effects of thermal stratification, beginning with hot functional testing, or obtain data through coiiective efforts to assess the extent of thermal stratification, thermal striping and piping displacements.

UFSAR AP1000 Conformance Statement for Requirement 2.c):

As part of the Westinghouse Owners Group program on surge line thermal stratification, Westinghouse collected surge line physical design and plant operational data for all domestic Westinghouse PWRs. In addition, Westinghouse collected surge line monitoring data from approximately 30 other plants. This experience was used in the development of the AP1000 thermal stratification loading calculations. As described in the AP1000 Conformance to Request 3 of Bulletin 88-11, monitoring will be performed during hot functional testing and during the first cycle of the first API 000 plant. This Combined License item is identified in Subsection 3.9.8.5. Subsequent monitoring of the API 000 surge line is not required.

Desian Discussion for Requirement 2.c):

As a part of the API 000 plant conformance to NRC Bulletin 88-11, a monitoring program was required to be implemented at the first API 000 unit to record temperature distributions and thermal displacement of the surge line during hot functional testing and the first fuel cycle.

The first API 000 plant, Sanmen Unit 1, monitored the temperature in the pressurizer surge line using temporary RTDs and displacement sensors, as well as, the three permanent plant RTDs during hot functional testing and the first fuel cycle. The steady state displacement and temperature measurements of the surge line at different plateaus during hot functional testing heat up and cooldown met the acceptance criteria as evaluated by Westinghouse.

NRC Bulletin 88-11 Requirement 2.d):

Applicants are requested to update stress and fatigue analyses, as necessary, to ensure Code compliance. The analyses should be completed no later than one year after issuance of the low power license.

UFSAR API 000 Conformance Statement for Reouirement 2.d1:

Revision of the stress and fatigue analyses is not required for the API 000 surge line, since the design analysis considers thermal stratification and thermal striping.

Design Discussion for Reouirement 2.d):

The thermal monitoring data collected from the first operating plant, Sanmen Unit 1, will be used to verify the inputs used in the pressurizer surge line design analysis. The data collected is representative of the data that would be collected at Vogtle Units 3 and 4 with first-cycle temporary instrumentation. It is unlikely that any additional insight into the temperature stratification phenomena will be gained by collecting additional data at Vogtle Units 3 and 4.

The evaluation of the data from the first operating plant will be included as a part of the as-built reconciliation of the RCS ASME Section III piping system, as described in UFSAR Section 3.9.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

Summary:

The design and functionality of the AP1000 pressurizer surge line is not impacted by this change. The change does not impact any permanent plant equipment. The AP1000 plant continues to conform to the requirements of NRG Bulletin 88-11. The COL and UFSAR requirements are to perform thermal monitoring of the pressurizer surge line during hot functional testing and the first operating cycle. This monitoring was performed at Sanmen Unit 1 and does not need to be re-performed at Vogtle Units 3 and 4. The data collected at Sanmen Unit 1 is representative of the data that would be collected at Vogtle Unit 3 and 4 with first-cycle temporary instrumentation, and it is unlikely that any additional insight into the temperature stratification phenomena would be gained by collection of additional data at Vogtle Units 3 and 4. Removal of the monitoring requirement is not an adverse change to the API 000 design.

3.2 Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) and ASME Code III Compliance The pressurizer surge line is identified in Table 2.1.2-2 of Appendix C of the Vogtle 3 and 4 COLs. One of the design commitments associated with the pressurizer surge line is described in ITAAC 2.1.02.02a (Index No. 13), which states: "[t]he piping identified in Table 2.1.2-2 as ASME Code Section III is designed and constructed in accordance with ASME Code Section III requirements." This ITAAC also has a design commitment that each of the as-built lines identified in Table 2.1.2-2 designated as LBB must meet the LBB criteria.

These ITAAC confirm and demonstrate that the as-built pressurizer surge line is correctly built and tested and that the design commitment for a mechanistic pipe break (LBB) evaluation of high-energy piping systems is completed. The use of mechanistic pipe break criteria represents a higher level of confidence of the integrity of piping systems based on additional criteria compared to the existing high level of integrity provided by the requirements of the ASME Code.

Design specifications and design reports for ASME Section III piping are made available for NRC review. Reconciliation of the as-built piping (verification of the thermal cycling and stratification loading) is completed after the construction of the piping systems and prior to fuel load.

3.3 Permanent Plant Pressurizer Surge Line Instrumentation There are three permanently installed, nonsafety-related, strap-on RTDs located on the RCS pressurizer surge line. These instruments continuously monitor the pressurizer surge line fluid temperature during plant normal operations in order to detect thermal stratification in the surge line. Two of the RTDs are located on a moderately sloped run approximately midway between the RCS hot leg and the pressurizer. One RTD is located on the bottom of the pipe and the other RTD on the top. The third RTD is located on the pressurizer surge line as close to the pressurizer nozzle as possible. This detector is used to monitor cold insurges to the pressurizer during transient operations.

Temperature indication from the permanently installed RTDs is provided in the main control room. One low temperature alarm is provided to alert the operator of thermal stratification in the surge line. This alarm is associated with the RTD on the bottom of the pipe. During heatup and cooldown operations, a differential temperature alarm indicates significant thermal Page 9 of 16

ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1) stratification using the difference between the temperatures measured at the top and bottom of the pipe.

The permanently installed RTDs will be tested as part of the initial test program as described in UFSAR Subsection 14.2.9.1.1.

3.4 First Plant Testing As part of the API 000 PWRs conformance to NRG Bulletin 88-11, the API 000 Design Control Document, as well as the site-specific licensing basis of Sanmen and Vogtle API 000 nuclear power plants, requires that a monitoring program be implemented for the first API 000 unit to record temperature distributions and thermal displacements of the surge line during hot functional testing and during the first fuel cycle (UFSAR sections 3.9.8.5, 14.2.5, 14.2.9.1.7 item d)).

The pressurizer surge line monitoring requirement is listed as one of the first plant only tests according to the UFSAR (Section 14.2.5). The first plant only tests are special tests to further establish a unique phenomenological performance parameter of the API 000 design features beyond testing performed for Design Certification of the AP600 and that will not change from plant to plant. Because of the standardization of the API 000 design, these special tests are not required for subsequently built plants.

Sanmen Unit 1 implemented a monitoring program to record temperature distributions and thermal displacements of the surge line piping during hot functional testing and during the first fuel cycle. The monitoring program followed the regulatory requirements and guidelines described above. The measurements started during hot functional testing and continued up to and during commercial operation.

The applicability of the Sanmen Unit 1 first plant surge line monitoring to Vogtle Units 3 and 4 was confirmed by verifying the systems, structures and components (SSCs) within the scope of the surge line monitoring requirement were designed using the same standard API 000 design requirements across Sanmen Unit 1 and Vogtle Units 3 & 4. Reviews were completed of design documents and operating procedures specific to the Sanmen Unit 1 surge line testing which confirmed there were no significant site-specific differences in either the as-built configurations or operating parameters that would preclude the testing results from being applied to Vogtle 3 and 4.

The hot functional testing procedure used by Sanmen 1 and which will be used by Vogtle Units 3 and 4 is applicable to all API 000 plants. The objectives of the test include:

test plateaus and sequence of tests constituting the precore hot functional test

program, demonstration that systems operate within design limits at each plateau, demonstration of integrated operation of plant systems under precore hot functional conditions, and provide coordination and establishment of initial conditions necessary for the conduct of preoperational tests to be performed during heat up, normal operating temperature and pressure and cooldown of the reactor coolant system.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

Sanmen Unit 1 heat up and cooldown procedures were compared with Vogtle 3 and 4 procedures and confirmed that the operational transients (i.e., test plateaus and sequence of tests) did not invalidate the surge line data from being used at Vogtle Units 3 and 4. The applicability of the pressurizer surge line monitoring data to Vogtle Units 3 and 4 was validated by verifying the systems, structures and components (SSCs) within the scope of the heat up and cooldown testing procedures were both designed and procured using the standard AP1000 design requirements as Sanmen Unit 1 and Vogtle Units 3 and 4. Reviews of design changes were completed which confirmed Sanmen Unit 1 did not implement changes that would cause the SSCs involved in the testing to be outside of the standard plant design such that the test performance would be impacted.

Vogtle Units 3 and 4 have ITAAC requirements associated with the SSCs involved in the pressurizer surge line monitoring requirement. Completion of these ITAAC will verify that Vogtle Units 3 and 4 are within the standard plant AP1000 design as described in the Vogtle Units 3&4 UFSAR. The reviews completed by SNC demonstrated the pressurizer surge line first plant only monitoring completed at Sanmen Unit 1 is applicable to Vogtle Units 3 and 4.

3.5 Summary In summary, the design and functionality of the pressurizer surge line is not impacted by this change because no design changes are proposed to any SSC. Vogtle Units 3 and 4 continue to conform to the requirements of NRC Bulletin 88-11. The COL and UFSAR requirements are to perform thermal monitoring of the pressurizer surge line at the first API 000 unit during hot functional testing and the first operating cycle.

The first plant Pressurizer Surge Line Stratification Evaluation testing is unnecessary at Vogtle Units 3 and 4 because: the API 000 plant was designed to account for thermal cycling and stratification and includes extensive industry operating experience; surge line piping is designed to ASME III and leak-before-break criteria that is confirmed through ITAAC; permanently installed RTDs located on the surge line monitor the fluid temperature to detect thermal stratification; and, because the applicability of the data collected during Sanmen Unit 1 first plant surge line monitoring to Vogtle Units 3 and 4 was confirmed and is representative of the API 000 standard design, it is unlikely that additional insight into the temperature stratification phenomena will be gained by collecting additional data at Vogtle Units 3 or 4.

Therefore, removal of the monitoring requirement is not an adverse change to Vogtle Units 3 and 4 or the API 000 design.

4. REGULATORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria 10 CFR Part 52.98(c) requires an amendment to the license for any modification to, addition to, or deletion from the terms and conditions of a combined license, including modification to, addition to, or deletion from the inspections, tests, analyses, or related acceptance criteria contained in the license. This change involves changes to UFSAR Subsections 14.2.5, 14.2.9.1.7, 14.2.9.2.22 and requires a revision to COL condition 2.D.(2)(a)1.

Therefore, a license amendment request (LAR) (as supplied herein) is required.

The design and functionality of the pressurizer surge line is not impacted by this change.

The change does not impact any permanent plant equipment. The API 000 plant continues Page 11 of 16

ND-19-1097 Ellminatlon of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1) to conform to the requirements of NRG Bulletin 88-11. Removal of the monitoring requirement is not an adverse change to the AP1000 design.

10 CFR Part 50, Appendix A, General Design Criterion (GDC) Criterion 1Quality standards and records, requires that structures, systems, and components (SSCs) important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. The proposed change to remove the requirement to monitor the pressurizer surge line for thermal stratification and thermal cycling during hot functional testing and during the first fuel cycle for the first plant only does not impact the existing design requirements for any SSCs important to safety. The proposed changes do not involve physical modifications or addition of systems, structures, and components. The remaining UFSAR Chapter 14 requirements ensure adequate testing of these SSCs. Thus, the proposed changes do not alter the design, fabrication, erection, or testing of SSCs important to safety, and the proposed changes comply with the requirements of GDC 1.

10 CFR Part 50, Appendix A, GDC Criterion 2Design bases for protection against natural phenomena, requires that structures, systems and components important to safety be designed to withstand the effects of natural phenomena, such as earthquakes. The proposed change to remove the requirement to monitor the pressurizer surge line for thermal stratification and thermal cycling during hot functional testing and during the first fuel cycle for the first plant only does not impact the existing seismic design requirements for the RCS, including seismic Category I requirements. The proposed change does not involve physical modifications or addition of systems, structures, and components, and does not impact the existing seismic design requirements. Therefore, the proposed changes comply with the requirements of GDC 2.

10 CFR Part 50, Appendix A, GDC Criterion 4Environmental and dynamic effects design bases,requires that systems, structures, and components can withstand the dynamic effects associated with missiles, pipe whipping, and discharging fluids, excluding dynamic effects associated with pipe ruptures, the probability of which is extremely low under conditions consistent with the design basis for the piping. The proposed change to remove the requirement to monitor the pressurizer surge line for thermal stratification and thermal cycling during hot functional testing and during the first fuel cycle for the first plant only proposed changes do not impact the existing design requirements for the RCS. The proposed changes do not involve physical modifications or addition of systems, structures, and components, and do not impact the existing capability of the RCS to withstand dynamic effects associated with missiles, pipe whipping, and discharging fluids as required by this criterion. Therefore, the proposed changes comply with the requirements of GDC 4.

10 CFR Part 50, Appendix A, GDC Criterion 14Reactor coolant pressure boundary, requires that the reactor coolant pressure boundary be designed, fabricated, erected, and tested so as to have an extremely low probability of abnormal leakage, of rapidly propagating failure, and of gross rupture. The proposed change to remove the requirement to monitor of the pressurizer surge line for thermal stratification and thermal cycling during hot functional testing and during the first fuel cycle for the first plant only, does not impact the existing design requirements for the RCS. The proposed change does not involve physical modifications or addition of systems, structures, and components, and does not impact the existing capability of the pressurizer surge line to perform the required reactor coolant pressure boundary functions. The API 000 plant was designed to account for thermal cycling and stratification and surge line piping is designed and tested to ASME Section III and leak-before-break criteria that is confirmed through ITAAC and is Page 12 of 16

ND-19-1097 Ellmination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1) representative of the AP1000 standard design. Therefore, the proposed changes comply with the requirements of GDC 14.

10 CFR Part 50, Appendix A, GDC Criterion 15Reactor cooiant system design, requires that the reactor coolant system and associated auxiliary, control, and protection systems shall be designed with sufficient margin to assure that the design conditions of the reactor coolant pressure boundary are not exceeded during any condition of normal operation, including anticipated operational occurrences. The proposed change to remove the requirement to install temporary instrumentation on the pressurizer surge line for thermal stratification and thermal cycling during hot functional testing and during the first fuel cycle for the first plant only, do not impact the existing design requirements for the RCS. The proposed change does not involve physical modifications or addition of systems, structures, and components, does not impact the existing capability of the pressurizer surge line to perform the required reactor coolant pressure boundary functions, and does not impact the existing auxiliary, control, and protection systems. The proposed changes do not impact permanent plant instrumentation necessary for monitoring and control of the RCS.

Therefore, the proposed changes comply with the requirements of GDC 15.

Regulatory Guide (RG) 1.68, Initial Test Programs for Water-Cooled Nuclear Power Plants, Revision 2 describes the Initial Test Program (ITP) requirements. The proposed changes to the Pressurizer Surge Line Stratification Evaluation first plant tests do not alter compliance with RG 1.68 and the SSCs within the scope of RG 1.68 are still included in the ITP. The proposed changes to the Pressurizer Surge Line Stratification Evaluation first plant tests do not adversely impact the UFSAR in terms of conformance to RG 1.68.

The proposed changes have been evaluated to determine whether applicable regulations continue to be met. It was determined that the proposed changes do not affect conformance with the applicable regulatory requirement. Regulatory Guides or General Design Criteria differently than as described in the plant-specific DCD or UFSAR.

4.2 Precedent No precedent was identified.

4.3 No Significant Hazards Consideration Anaiysis The requested amendment involves changes to eliminate the performance of the Pressurizer Surge Line Stratification Evaluation first plant test at VEGP Units 3 and 4, by revising the COLs and UFSAR Subsections 14.2.5, 14.2.9.1.7 and 14.2.9.2.22.

The first plant Pressurizer Surge Line Stratification Evaluation testing is unnecessary at Vogtle Units 3 and 4 because: the API 000 plant was designed to account for thermal cycling and stratification; surge line piping is designed to ASME III and leak-before-break criteria that is confirmed through ITAAC; permanently installed RTDs located on the surge line monitor the fluid temperature to detect thermal stratification; and, because the data collected at Sanmen Unit 1 is representative of the API 000 design, it is unlikely that additional insight into the temperature stratification phenomena will be gained by collecting more data at Vogtle Units 3 or 4.

An evaluation to determine whether or not a significant hazards consideration is involved with the proposed amendment was completed by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment," as discussed below.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAP-19-013R1) 4.3.1 Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed change does not affect the operation of any systems or equipment that Initiates an analyzed accident or alter any structures, systems, or components accident Initiator or Initiating sequence of events. The proposed changes remove the requirement to perform the Pressurizer Surge Line Stratification Evaluation first plant tests based on a number of factors that render the testing unnecessary. The changes do not adversely affect any methodology which would Increase the probability or consequences of a previously evaluated accident.

The change does not Impact the support, design, or operation of mechanical or fluid systems. There Is no change to plant systems or the response of systems to postulated accident conditions. There Is no change to predicted radioactive releases due to normal operation or postulated accident conditions. The plant response to previously evaluated accidents or external events Is not adversely affected, nor does the proposed change create any new accident precursors.

The proposed changes do not Involve a change to any mitigation sequence or the predicted radiological releases due to postulated accident conditions, thus, the consequences of the accidents evaluated In the UFSAR are not affected.

Therefore, the proposed amendment does not Involve a significant Increase In the probability or consequences of a previously evaluated accident.

4.3.2 Does the proposed amendment create the possibiiity of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed changes remove the requirement to perform the Pressurizer Surge Line Stratification Evaluation first plant tests based on a number of factors that render the testing unnecessary. The proposed changes do not adversely affect any design function of any SSC design functions or methods of operation In a manner that results In a new failure mode, malfunction, or sequence of events that affect safety-related or non-safety-related equipment. This proposed change does not allow for a new fission product release path, result In a new fission product barrier failure mode, or create a new sequence of events that result In significant fuel cladding failures.

These proposed changes do not adversely affect any other SSC design functions or methods of operation In a manner that results In a new failure mode, malfunction, or sequence of events that affect safety-related or nonsafety-related equipment. Therefore, this proposed change does not allow for a new fission product release path, result In a new fission product barrier failure mode, or create a new sequence of events that results In significant fuel cladding failures.

Therefore, the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

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ND-19-1097 Elimination of License Condition to Evaluate Pressurlzer Surge Line Stratification (LAR-19-013R1) 4.3.3 Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No The proposed change maintains existing safety margin and provides adequate protection through continued application of the existing design requirements In the UFSAR. The proposed change satisfies the same design functions In accordance with the same codes and standards as stated In the UFSAR. This change does not adversely affect any design code, function, design analysis, safety analysis Input or result, or design/safety margin.

No safety analysis or design basis acceptance llmlt/crlterlon Is challenged or exceeded by this change, and no significant margin of safety Is reduced.

Therefore, the proposed change does not Involve a significant reduction In a margin of safety.

Based on the above. It Is concluded that the proposed amendment does not Involve a significant hazards consideration under the standards set forth In 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" Is justified.

4.4 Conclusions This assessment addresses the considerations discussed above. The plant licensing basis, safety analyses, and design bases evaluations demonstrate that the requested change Is accommodated without an Increase In the probability or consequences of an accident previously evaluated, without creating the possibility of a new or different kind of accident from any accident previously evaluated, and without a significant reduction In the margin of safety. In conclusion, based on the considerations discussed above, (1) there Is a reasonable assurance that the health and safety of the public will not be endangered by operation In the proposed manner, (2) such activities will be conducted In compliance with the Commission's regulations, and (3) the Issuance of the amendment will not be Inimical to the common defense and security or to the health and safety of the public. Having arrived at negative declarations with regard to the criteria of 10 CFR 50.92, this assessment determined that the requested change does not Involve a Significant Hazards Consideration.

5. ENVIRONMENTAL GGNSiDERATIGNS This review supports a request to amend the Combined License (COL) to revise the element of the certification Information related to Pressurlzer Surge Line Stratification Evaluation first plant tests requirements In Updated Final Safety Analysis Report (UFSAR) and COL Condition 2.D.(2)(a)1.

Sections 2 and 3 of this license amendment request provide the details of the proposed change.

The Licensee has determined that the anticipated construction and operational effects of the proposed amendment meet the eligibility criteria for categorical exclusion set forth In 10 CFR 51.22(c)(9), In that:

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ND-19-1097 Elimination of License Condition to Evaluate Pressurizer Surge Line Stratification (LAR-19-013R1)

(i)

There is no significant hazards consideration.

As documented in Section 4.3, Significant Hazards Consideration, of this license amendment request, an evaluation was completed to determine whether or not a significant hazards consideration is involved by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment." The significant hazards consideration determined that (1) the requested amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated; (2) the requested amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated; and (3) the requested amendment does not involve a significant reduction in a margin of safety. Therefore, it is concluded that the requested amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and accordingly, a finding of "no significant hazards consideration" is justified.

(ii)

There is no significant change in the types or significant increase in the amounts of any effiuents that may be released offsite.

The proposed change is unrelated to any aspect of plant construction or operation that would introduce any change to effluent type (e.g., effluents containing chemicals or biocides, sanitary systems effluents, and other effluents), or affect any plant radiological or non-radiological effluent release quantities. Furthermore, the proposed changes do not affect any effluent release path or diminish the design function or operational features that are credited with controlling the release of effluents during plant operation. Therefore, it is concluded that the requested amendment does not involve a significant change in the types or a significant increase on the amounts of any effluents that may be released offsite.

(Hi) There is no significant increase in individual or cumulative occupational radiation exposure.

The proposed changes do not adversely affect walls, floors, or other structures that provide shielding. Plant radiation zones are not affected, and there are no changes to the controls required under 10 CFR Part 20 that preclude a significant increase in occupational radiation exposure. Therefore, the requested amendment does not involve a significant increase in individual or cumulative occupational radiation exposure.

Based on the above review of the requested amendment, it has been determined that the anticipated construction and operational impacts of the requested amendment do not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, and (iii) a significant increase in the individual or cumulative occupational radiation exposure. Accordingly, the requested amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection the requested amendment.

6. REFERENCES None.

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