RS-19-076, Supplement to License Amendment Request to Increase Technical Specifications Allowable MSIV Leakage Rates

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Supplement to License Amendment Request to Increase Technical Specifications Allowable MSIV Leakage Rates
ML19203A176
Person / Time
Site: Quad Cities  Constellation icon.png
Issue date: 07/22/2019
From: Simpson P
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-19-076
Download: ML19203A176 (6)
v • d • e


Text

4300 Winfield Roacl Warrenville. IL 60555 Exelon Genera tion 630 65 7 2000 Office RS-19-076 10 CFR 50.12 July 22, 2019 U. S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, D.C. 20555-0001 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265

Subject:

Supplement to License Amendment Request to Increase Technical Specifications Allowable MSIV Leakage Rates

Reference:

In the referenced letter, Exelon Generation Company, LLC (EGC), requested an amendment to revise the Main Steam Isolation Valve (MSIV) leakage rate limits in Quad Cities Nuclear Power Station (QCNPS) , Units 1 and 2 Technical Specifications (TS). Specifically, Technical Specification 3.6.1 .3, "Primary Containment Isolation Valves (PCIVs) ," Surveillance Requirement (SR) 3.6.1.3.10. The proposed changes to the leakage rate limits are based on a revised radiological consequences analysis of the design basis loss of coolant accident (LOCA).

As indicated in the referenced letter, the revised dose analysis models MSIV leakage in a manner that supports aligning QCNPS, Units 1 and 2 with the common industry practice of monitoring MSIV leakage separate from the station TS allowable leakage, La, totals .

In accordance with 10 CFR 50.12, "Specific exemptions," Paragraphs (a)(1) and (a)(2)(ii), EGC is requesting NRC approval of a permanent exemption from the requirements of 10 CFR 50.54(0) and 10 CFR 50 , Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors ," Option B, "Performance-Based Requirements ,"

Paragraphs Ill.A, "Type A Test," and 111.B, "Type Band C Tests," as a supplement to the referenced licensing action. EGC requests the exemption to allow exclusion of MSIV pathway leakage from the overall integrated leakage rate measured when performing a Type A Test, and the requirements of 10 CFR 50, Appendix J, Option B, Paragraph 111.B, to allow exclusion of the MSIV pathway leakage from the combined leakage rate of all penetrations and valves subject to Type B and C tests.

This exemption will allow the leakage testing to be performed in a manner consistent with the way MSIV leakage is modeled in the revised radiological consequence analysis. The

July 22 , 2019 U. S. Nuclear Regulatory Commission Page 2 attachment to this letter provides the rationale and justification for the exemption request. The requested exemption from certain requirements in 10 CFR 50, Appendix J, Option Bis permissible under 10 CFR 50.12 because it is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. In addition , special circumstances are present such that the application of 10 CFR 50, Appendix J, Option B, Paragraph Ill.A and 111.B in this instance would not serve the underlying purpose of the rule.

In accordance with 10 CFR 50.91 , "Notice for public comment; State consultation ,"

paragraph (b), EGC is notifying the State of Illinois of this supplement to the referenced application for l[cense amendments by transmitting a copy of this letter and its attachment to the designated State of Illinois official.

There are no regulatory commitments contained in this letter. Should you have any questions concerning this submittal , please contact Ms. Rebecca L. Steinman at (630) 657-2831.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 22nd day of July, 2019.

spectfully, K.

Patrick R. Simpson Sr. Manager Licensing

Attachment:

Proposed Exemption to Certain 10 CFR 50 , Append ix J, Option B Requirements cc : NRC Regional Administrator - Region Ill NRC Senior Resident Inspector - Quad Cities Station NRC Project Manager, NRR - Quad Cities Station Illinois Emergency Management Agency - Division of Nuclear Safety

ATTACHMENT Proposed Exemption to Certain 10 CFR 50, Appendix J, Option B Requirements

1. SPECIFIC EXEMPTION REQUEST 10 CFR 50.54(0) requires that primary reactor containments be subjected to the requirements of 1 O CFR 50 , Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." Append ix J specifies the leakage rate test requirements, schedules, and acceptance criteria for tests of the leak-tight integrity of the primary reactor containment and systems and components that penetrate containment.

10 CFR 50, Appendix J, Option B, "Performance-Based Requirements ," Paragraphs Ill.A, "Type A Test," requires that the overall integrated leakage rate (i.e., Type A test) must not exceed the allowable leakage (La) with margin , as specified in the Technical Specifications (TS) .

Paragraph 111.B, "Type Band C Tests," requires the sum of the leakage of Type Band Type C local leakage rate tests to be less than the performance criterion (La) with margin as specified in the TS. As specified in the 10 CFR 50 Appendix J definitions , the overall integrated leakage rate is the total leakage rate from all tested leakage paths, including contributions from containment welds, valves, fittings, and components that penetrate the containment. The four main steam line penetrations are included in this definition of overall integrated leakage rate.

The Main Steam Isolation Valve (MSIV) leakage pathway consists of the combined leakage of the four main steam lines where each line contains two MSIVs in series and is tested in accordance with TS Surveillance Requirement (SR) 3.6.1.3.10.

In accordance with 10 CFR 50.12, "Specific exemptions," Exelon Generation Company, LLC (EGC) requests an exemption from the requirements of 1 O CFR 50, Appendix J, Option B, Paragraphs Ill.A and 111.B for Quad Cities Nuclear Power Station (QCNPS) , Units 1 and 2. The proposed exemption would permit exclusion of the MSIV leakage contribution from the overall integrated leakage rate Type A test measurement and from the sum of the leakage rates from Type B and Type C tests. This exemption will allow the leakage testing to be performed in a manner consistent with the way MSIV leakage is modeled in the revised radiological consequence analysis submitted as part of Reference 1.

2. BASIS FOR EXEMPTION REQUEST 1 O CFR 50 , Appendix J testing ensures primary containment leakage following a design basis loss-of-coolant accident (LOCA) will be within the allowable leakage limits specified in plant TS and assumed in the safety analysis for determining radiological consequences. The QCNPS, Units 1 and 2 Primary Containment Leakage Rate Testing Program as described in Technical Specification 5.5.12 , "Primary Containment Leakage Rate Testing Program, complies with 1 O CFR 50, Appendix J, Option B provisions for Type A, Type Band Type C tests . MSIV leakage cu rrently is included in the Type A overall containment integrated leakage rate total and added to the combined Type B and C leakage rate total. However, the radiological consequences of MSIV leakage are modeled as a separate primary containment release path to the environment that bypasses secondary containment and therefore it is not filtered through the standby gas treatment system like other containment leakage. The LOCA dose calculation assumes all MSIV leakage migrates to the Turbine Building and then to the environment.

EGC requests a permanent exemption for QCNPS, Units 1 and 2 from : 1) the requirements of 1 O CFR 50, Appendix J, Option B, Paragraph Ill.A, to allow exclusion of the MSIV leakage from the overall integrated leakage rate measured when performing a Type A test, and 2) the Page 1

ATTACHMENT Proposed Exemption to Certain 10 CFR 50, Appendix J, Option B Requirements requirements of 10 CFR 50 , Appendix J, Option B, Paragraph 111.B, to allow exclusion of the MSIV leakage from the combined leakage rate of all penetrations and valves subject to Type B and C tests. Approval of this exemption request will more closely align the OCNPS, Units 1 and 2 Primary Containment Leakage Rate Testing Program with the assumptions used in the accident consequence analyses.

On March 5, 2019, EGC submitted a license amendment request (LAR) to revise the combined MSIV leakage rate limit for all four steam lines given in Technical Specification 3.6.1.3, "Primary Containment Isolation Valves (PCIVs) ," SR 3.6.1.3.1 O (i.e., Reference 1). The revised MSIV leakage rates are based on a revised dose consequence calculation that models the main steam pathway leakage separate from the remainder of the assumed leakage from primary containment (i.e., MSIV leakage at TS defined leakage rate in addition to containment leakage of 100% La) and demonstrates that the resulting dose consequences continue to meet the acceptance criteria of 10 CFR 50.67 and 10 CFR 50 , Appendix A, GDC 19. The Technical Specification 5.5.12 La leakage value of 3.0 weight percent per day is unchanged by this exemption request or Reference 1.

3. EXEMPTION JUSTIFICATION
a. The exemption is authorized by law 10 CFR 50.12(a)(1) requires a demonstration that an exemption from NRC regulations is authorized by law. The proposed exemption is authorized by law and has been previously granted to other licensees as described in Section 5 below.
b. The exemption will not present undue risk to public health and safety 10 CFR 50.12(a)(1) requires a demonstration that the granting of an exemption from the requirement in question "will not present an undue risk to the public health and safety." The exemption presents no undue risk to public health and safety. MSIV leakage for the revised QCNPS Design Basis Accident (OBA) analysis has been accounted for separately from the overall leakage associated with the primary containment boundary (i .e., Type A) and local leakage rate total (i.e., Type Band C) (e.g ., MSIV leakage is separate from the maximum TS allowable leakage , La). As such , the inclusion of MSIV leakage as part of Type A and as part of Type B and C test results is not necessary to ensure the actual radiological consequences of DBA's remain below the regulatory limit. Since the exemption will not result in a significant change to the previously evaluated consequences associated with DBAs, the proposed exemption presents no undue risk to public health and safety.
c. The exemption is consistent with the common defense and security The term "common defense and security" refers principally to the safeguarding of special nuclear material , the absence of foreign control over the applicant, the protection of Restricted Data, and the availability of special nuclear material for defense needs. The granting of the requested exemption to remove MSIV leakage from La will not affect any of these and, thus, such grants are consistent with the common defense and secu rity. Further, the potential impact on public health and safety has been determined to be inconsequential.

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ATTACHMENT Proposed Exemption to Certain 10 CFR 50, Appendix J, Option B Requirements

4. SPECIAL CIRCUMSTANCES 10 CFR 50.12 states that the NRG will not consider granting an exemption unless special circumstances are present. This request meets the criterion of a special circumstance as defined in 10 CFR 50.12(a)(2)(ii), which states, "Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule."

The pertinent rule is 10 CFR 50, Appendix J, Option B, Paragraphs Ill.A and 111.B, which state in part that:

a) Type A Test leakage rate must not exceed the allowable leakage rate (La) with margin, as specified in the TS.

b) Type Band C Tests must demonstrate that the sum of the leakage rates at accident pressure of Type B tests, and pathway leakage rates from Type C tests , is less than the performance criterion (La) with margin, as specified in the TS.

The underlying purpose of the rule is to ensure that the radiological consequences of DBAs remain below the applicable regulatory limits and are supported by the actual, periodic measurement of containment leakage (Type A) and local leakage rate measurement (Type B and C). Although Type A and Type Band C leakage tests are defined as a measurement of those leakages, inclusion of the MSIV leakage results in double counting , once as a part of the actual containment leakage and again as part of MSIV leakage used in dose calculations. This exemption resolves the special circumstance in which requiring inclusion of MSIV leakage in the Type A and Type B and C leakage is not necessary to achieve the underlying purpose of the rule.

5. PRECEDENTS The requested exemption will align OCNPS with the common industry practice of monitoring MSIV leakage separate from the station allowable leakage, La, totals. Examples of recent similar exemptions requested granted by the NRG include:
  • "Monticello Nuclear Generating Plant - Issuance of Exemption to Certain 10 CFR Part 50, Appendix J, Requirements," dated December 7, 2006 (Reference 2)
  • "Browns Ferry Nuclear Plant, Units 2 and 3 - Issuance of Exemption from 10 CFR Part 50, Appendix J," dated March 14, 2000 (Reference 4)
6. ENVIRONMENTAL IMPACT In accordance with 10 CFR 51.30 and 10 CFR 51.32, the following information is provided in support of an environmental assessment and finding of no significant impact for the proposed action.

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ATTACHMENT Proposed Exemption to Certain 10 CFR 50, Appendix J, Option B Requirements The exemption does not cause additional construction or operational activities to be conducted that may significantly affect the environment. No plant configuration changes are required. The exemption does not result in an increase in adverse environmental impact previously evaluated, does not result in a significant change to normal offsite effluents or power levels, and does not affect any matter not previously reviewed by the NRC which may have a significant adverse environmental impact.

The exemption does not alter the land use for the plant; water uses or impacts on water quality; air or ambient air quality. It does not affect the ecology of the site and vicinity and does not affect the noise emitted by the station. In addition, the proposed exemption request does not affect non-radiological plant effluents and has no other environmental impact.

Therefore, the proposed exemption does not affect the analysis of environmental impacts described in the environmental report.

7. CONCLUSION As demonstrated above, this request for an exemption from the requirements of 10 CFR 54(o) and the requirements of 10 CFR 50, Appendix J, Option B, Paragraph Ill.A, and Paragraph 111.B meet the criteria of 10 CFR 50.12 for specific exemptions. Specifically, the requested exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. In addition, the special circumstances described in 10 CFR 50.12(a)(2)(ii) are present and warrant issuance of the exemption.
8. REFERENCES
1. Letter from P.R. Simpson (EGC) to U.S. NRC , "Application to Increase Technical Specifications Allowable MSIV Leakage Rates and Revise Secondary Containment Surveillance Requirement 3.6.4.1 .1," dated March 5, 2019 (ADAMS Accession No. ML190648369)
2. Letter from P.S . Tam (U.S. NRC) to J.T. Conway (Nuclear Management Company. LLC),

"Monticello Nuclear Generating Plant - Issuance of Exemption to Certain 10 CFR Part 50, Appendix J, Requirements," dated December 7, 2006 (ADAMS Accession No. ML062410507)

3. Letter from R.B . Ennis (U.S. NRC) to M. Kansler (Entergy Nuclear Operations Inc),

"Vermont Yankee Nuclear Power Station - Issuance of Exemption from 10 CFR Part 50 ,

Appendix J," dated March 17, 2005 (ADAMS Accession No. ML041310359)

4. Letter from W.O. Long (U.S. NRC) to J.A. Scalice (Tennessee Valley Authority), "Browns Ferry Nuclear Plant, Units 2 and 3 - Issuance of Exemption from 10 CFR Part 50, Appendix J," dated March 14, 2000 (ADAMS Accession No. ML003691985)

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