ML063550429

License Amendment, LPCI Loop Select Logic Time Delay Relay Surveillance Interval

ML063550429
Person / Time
Site:	Monticello
Issue date:	01/18/2007
From:	Tam P NRC/NRR/ADRO/DORL/LPLIII-1
To:	Conway J Nuclear Management Co
P. TAM
Shared Package
ML070220100	List: ML063550429 ML070190034
References
TAC MD3580
Download: ML063550429 (13)

Text

January 18, 2007 Mr. John T. Conway Site Vice President Monticello Nuclear Generating Plant Nuclear Management Company, LLC 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - ISSUANCE OF AMENDMENT RE: ONE-TIME EXTENSION OF LOW PRESSURE COOLANT INJECTION LOOP SELECT LOGIC TIME DELAY SURVEILLANCE INTERVAL (TAC NO. MD3580)

Dear Mr. Conway:

The Commission has issued the enclosed Amendment No. 149 to Renewed Facility Operating License No. DPR-22 for Monticello Nuclear Generating Plant (MNGP), in response to your application dated November 14, 2006, as supplemented on December 28, 2006.

The amendment revises Table 3.3.5.1-1, Emergency Core Cooling System Instrumentation, of the MNGP Technical Specifications, to permit a one-time extension of the quarterly surveillance interval (i.e., from 92 days to 140 days), for three low pressure coolant injection loop select logic functions.

A copy of the Nuclear Regulatory Commission staffs related safety evaluation is also enclosed.

The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely,

/RA/

Peter S. Tam, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosures:

1. Amendment No. 149 to DPR-22

2. Safety Evaluation cc w/encls: See next page

January 18, 2007 Mr. John T. Conway Site Vice President Monticello Nuclear Generating Plant Nuclear Management Company, LLC 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - ISSUANCE OF AMENDMENT RE: ONE-TIME EXTENSION OF LOW PRESSURE COOLANT INJECTION LOOP SELECT LOGIC TIME DELAY SURVEILLANCE INTERVAL (TAC NO. MD3580)

Dear Mr. Conway:

The Commission has issued the enclosed Amendment No. 149 to Renewed Facility Operating License No. DPR-22 for Monticello Nuclear Generating Plant (MNGP), in response to your application dated November 14, 2006, as supplemented on December 28, 2006.

The amendment revises Table 3.3.5.1-1, Emergency Core Cooling System Instrumentation, of the MNGP Technical Specifications, to permit a one-time extension of the quarterly surveillance interval (i.e., from 92 days to 140 days), for three low pressure coolant injection loop select logic functions.

A copy of the Nuclear Regulatory Commission staffs related safety evaluation is also enclosed.

The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely,

/RA/

Peter S. Tam, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosures:

1. Amendment No. 149 to DPR-22

2. Safety Evaluation cc w/encls: See next page DISTRIBUTION PUBLIC LPL3-1 r/f RidsNrrDorlLpl3-1 RidsNrrPMPTam RidsNrrLATHarris RidsOGCRp RidsAcrsAcnwMailCenter RidsNrrDirsltsb G. Hill, OIS RidsRgn3MailCenter RidsNrrDorlDpr BParks, SBWB C. Doutt Package Accession No.: ML070220100 Amendment Accession No.: ML063550429 Tech. Spec. pages Accession No.: ML070190034 OFFICE LPL3-1/PM LPL3-1/LA LPL3-1 SBWB/BC APLA/BC OGC LPL3-1/BC NAME PTam THarris PTam for DWright GCranston* MRubin* PMoulding LRaghavan DATE 12/29/06 12/28/06 12/29/06 1/5/07 12/21/06* 1/12/07 12/29/06

• Safety evaluation transmitted by memo on date shown.

OFFICIAL RECORD COPY

NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-263 MONTICELLO NUCLEAR GENERATING PLANT AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 149 License No. DPR-22

1. The Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Nuclear Management Company, LLC (the licensee), dated November 14, 2006, as supplemented on December 18, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.2 of Facility Operating License No. DPR-22 is hereby amended to read as follows:

Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 149 are hereby incorporated in the license. NMC shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance and shall be implemented within 30 days.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

L. Raghavan, Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: January 18, 2007

ATTACHMENT TO OPERATING LICENSE AMENDMENT NO. 149 RENEWED FACILITY OPERATING LICENSE NO. DPR-22 DOCKET NO. 50-263 Replace the following page of Renewed Facility Operating License DPR-22 with the attached revised page. The revised page is identified by amendment number and contains a marginal line indicating the area of change.

3 3 Replace the following pages of Appendix A (Technical Specifications) with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

REMOVE INSERT 3.3.5.1-8 3.3.5.1-8 3.3.5.1-9 3.3.5.1-9

2. Pursuant to the Act and 10 CFR Part 70, NMC to receive, possess, and use at any time special nuclear material as reactor fuel, in accordance with the limitations for storage and amounts required for reactor operations, as described in the Final Safety Analysis Report, as supplemented and amended, and the licensees filings dated August 16, 1974 (those portions dealing with handling of reactor fuel) and August 17, 1977 (those portions dealing with fuel assembly storage capacity);

3. Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NMC to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required;

4. Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NMC to receive, possess, and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and

5. Pursuant to the Act and 10 CFR Parts 30 and 70, NMC to possess, but not separate, such byproduct and special nuclear material as may be produced by operation of the facility.

C. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission, now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

1. Maximum Power Level NMC is authorized to operate the facility at steady state reactor core power levels not in excess of 1775 megawatts (thermal).

2. Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 149, are hereby incorporated in the license. NMC shall l operate the facility in accordance with the Technical Specifications.

3. Physical Protection NMC shall implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Renewed License No. DPR-22 Amendment No. 1 thru 149 l

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR AMENDMENT NO. 149 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-22 NUCLEAR MANAGEMENT COMPANY, LLC MONTICELLO NUCLEAR GENERATING PLANT (MNGP)

DOCKET NO. 50-263

1.0 INTRODUCTION

By letter dated November 14, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML063190116), as supplemented by letter dated December 28, 2006 (Accession No. ML063630253), Nuclear Management Company (NMC), the licensee for MNGP, proposed to amend Renewed Facility Operating License No. DPR-22 to revise plant Technical Specification (TS) 3.3.5.1, Emergency Core Cooling System (ECCS) Instrumentation.

Specifically, the requested amendment would extend surveillance intervals as indicated in TS Table 3.3.5.1-1 for the following low pressure coolant injection (LPCI) loop select logic surveillance requirements:

2.k. Reactor Steam Dome Pressure - Time Delay Relay (Break Detection) 2.l. Recirculation Pump Differential Pressure - Time Delay Relay (Break Detection) 2.m. Recirculation Riser Differential Pressure - Time Delay Relay (Break Detection)

Performance of quarterly channel functional tests and calibration of these relays is required in accordance with the Improved Standard TS (ISTS, which were recently implemented at MNGP) by January 29, 2007. The licensee requested a one-time extension of the surveillance test interval (from 92 days to 140 days) for these time delay relays until the surveillances can be performed with the unit shutdown during an upcoming refueling outage.

The licensee's December 28, 2006, supplement provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the Nuclear Regulatory Commission (NRC) staff's original proposed no significant hazards consideration determination as published in the Federal Register on December 19, 2006 (71 FR 75995).

2.0 REGULATORY EVALUATION

Surveillance requirements are required to be in the TSs under the provisions of paragraph (c)(3) of Section 36 to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50.36(c)(3)). Surveillance requirements are requirements related to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

MNGP was licensed and constructed prior to the implementation of Appendix A to Title 10 of the Code of Federal Regulations, General Design Criteria (GDCs). Therefore, MNGP is not licensed to the GDCs. Section 1.2 of the MNGP Updated Safety Analysis Report (USAR) lists the principal design criteria (PDC) for the design, construction, and operation of the plant and USAR Appendix E provides a plant comparative evaluation to the proposed 70 Atomic Energy Commission (AEC) design criteria. The licensee reviewed the USAR and determined that the following regulatory criteria proposed by the AEC were applicable:

Criterion 38 - Reliability and Testability of Engineered Safety Features. GDC 38 states that all engineered safety features shall be designed to provide high functional reliability and ready testability. In determining the suitability of a facility for a proposed site, the degree of reliance upon and acceptance of the inherent features will be influenced by the known and demonstrated performance capability and reliability of the systems and by the extent to which the operability of such systems can be tested and inspected where appropriate during the life of the plant.

Criterion 46 - Testing of ECCS Components. GDC 46 requires that design provisions are made so that active components of the emergency core cooling systems, such as pumps and valves, can be tested periodically for operability and required functional performance.

The NRC staff found that the licensee has identified the appropriate proposed GDCs, and found them to be analogous to GDC 36, Inspection of Emergency Core Cooling System, and GDC 37, Testing of Emergency Core Cooling System, as currently published in Appendix A of 10 CFR Part 50.

3.0 TECHNICAL EVALUATION

In a General Electric Boiling Water Reactor 3 (BWR/3) reactor such as MNGP, the LPCI system is designed, as a part of the ECCS, to restore and maintain the coolant inventory in the reactor vessel so that the core is adequately cooled after a loss of coolant accident (LOCA).

The LPCI system operates in conjunction with the high pressure coolant injection system, the automatic depressurization system, and the core spray system to achieve this goal.

The LPCI system is designed to operate at low pressure and high flow to reflood the reactor core to at least two-thirds core height and to maintain this level. It operates after the reactor pressure vessel has depressurized. Inadvertent alignment and actuation of the LPCI system while the reactor is at pressure could result in an interfacing systems LOCA. At MNGP, the LPCI system uses the residual heat removal pumps to draw suction from the suppression pool and discharge water to one of the recirculation loops. A logic system in place is designed to detect differences in pressure between the two loops, which would be indicative of a recirculation line break, and select the recirculation loop with higher pressure for discharge.

Three time-delay relays (listed above under INTRODUCTION) are installed in the logic system to provide for detection of a possible recirculation line break. Together, the time-delay relays contribute to approximately 3 seconds of delay in the LPCI initiation sequence.

3.1 Reason for the Proposed Change The ISTS for BWR/4, which were recently implemented at MNGP, require surveillance testing and calibration of the LPCI loop select logic on a quarterly basis. The logic system at MNGP is testable in conformance with the specified design criteria; however, it is not designed to be tested online. The licensee identified four possible scenarios that would lead to plant transients if the LPCI loop select logic surveillance and calibration were performed online as required in the ISTS. The NRC staff agrees that the proposed change to the TS would preclude transients caused by performance of the newly-required surveillance tests.

3.2 NRC Staffs Deterministic Evaluation The licensee proposed a one-time extension to the LPCI loop select logic surveillance requirements. This proposed change to the TS does not involve any change to the design of the LPCI system. Since the testability of the LPCI system is not being altered, and the existing surveillance requirements are not being deleted, the NRC staff concludes that the proposed modified surveillance interval is in compliance with 10 CFR 50.36(c)(3), and the MNGP design and operation will continue to comply with its PDCs as discussed in REGULATORY EVALUATION above.

The licensee stated that the proposed surveillance test interval increase would result in performance of surveillance tests in accordance with old interval requirements (i.e., in the former custom TSs) that were in place prior to the licensees implementation of the ISTS. The licensee further stated that these surveillance tests assured operability of the LPCI loop select logic system time-delay relays. The NRC staff requested that the licensee provide documentation of the three most recent surveillances that showed that the LPCI loop select logic system time delay relays were functional. The licensee provided this documentation in its December 28, 2006, letter; the NRC staff reviewed the documentation and concluded that the recent test results demonstrated that the LPCI loop select logic system time delay relays remain in functional condition. The NRC staff concluded, based on the recent test results, that surveillance performed under the proposed surveillance test interval increase will continue to demonstrate the functionality of the subject time-delay relays.

The NRC staff reviewed the licensees USAR and determined that the LPCI initiation logic sequence requires approximately 87 seconds from receipt of initiation signal to complete LPCI initiation. By comparison, the total time delay contributed by the loop select time-delay relays is approximately 3 seconds. If time-delay relays for which the surveillance test interval increase is requested were to drift, the change in time delay would be comparatively small in consideration of the required 87 seconds from receipt of initiation signal to LPCI injection initiation.

Therefore, a change in the loop select time delay would result in little to no effect on a LOCA scenario. Therefore, on the basis that the possible contribution from out-of-calibration time-delay relays to a LOCA scenario is negligible, the NRC staff concludes that the proposed surveillance test interval increase is acceptable.

3.3 NRC Staffs Risk-Insight-Based Evaluation The licensees application confirmed that the proposed amendment was not risk-informed but was based on a deterministic analysis. However, the licensee did provide risk insights from a plant-specific MNGP probabilistic risk assessment (PRA) of the proposed change.

The scope of the NRC staffs review was limited to the evaluation of the risk impact and potential risk implications of the licensees application for amendment per the guidance of NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants, Chapter 19, Use of Probabilistic Risk Assessment in Plant-Specific, Risk-Informed Decisionmaking, Appendix D, Use of Risk Information in Review on Non-Risk-Informed License Amendment Requests. Appendix D provides review and assessment guidance on whether a special circumstance exists such that the normal presumption of adequate protection is no longer met by compliance with existing regulatory requirements for license amendment requests that are not risk-informed. Per the guidance given in Appendix D, the NRC staff used the risk-informed decisionmaking process in Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, in its review. Although the RG 1.174 acceptance guidelines by themselves do not constitute a definition of adequate protection, they do provide an appropriate set of criteria to be used in the initial process of evaluating adequate protection and provide a basis for finding that there is reasonable assurance of adequate protection.

The primary purpose of surveillance testing is to enssure that the components in a standby system (e.g., a safety system) will be operable when needed. The risk contribution associated with the surveillance test interval is mainly due to the possibility that the component may fail between consecutive tests. By testing these components, failures can be detected that may have occurred since the last surveillance and the risk due to undetected failures can be limited.

However, increasing the time between surveillance tests may also have some benefits.

Increased surveillance intervals may reduce test-induced transients, test-caused failures, equipment wear, and resources needed for testing. The disadvantage is the time a component will be subject to failure (the fault exposure time) will increase with an increased surveillance test interval.

The licensee modified the MNGP average maintenance PRA model to reflect the increased LPCI loop select logic time delay relay mean fault exposure time (increased time delay relay failure rate) for the increased surveillance test interval. In addition, the licensee assumed that the loop select logic always selects the wrong recirculation loop for injection, which is a conservative assumption. The LPCI loop select logic is only required for a recirculation line break LOCA. The importance of the loop select feature is limited by the LPCI recirculation loop LOCA event break sizes. For the higher probability break size of less than 3 inches, the licensee stated that adequate core cooling is maintained with the assumed failure of the LPCI loop select logic to select the unbroken recirculation loop. For breaks larger than 3 inches, the assumed failure of the LPCI loop select logic to select the unbroken recirculation loop will result in LPCI failure for recirculation LOCA events. Therefore, the impact is limited to lower probability medium and large break LOCAs on the recirculation line.

The licensee also stated that the time delay relays are currently included in the integrated emergency core cooling system testing performed each refueling outage. In the December 28, 2006, supplement the licensee confirmed that the last three refueling outage functional tests were performed successfully.

Based on the above, the licensee estimated a delta core damage frequency (CDF) of less than 1.0E-9 for the proposed one-time extended time delay relay surveillance test interval. This is considered very small per RG 1.174. The licensee also stated that the delta large early release frequency (LERF) also remains below the very small acceptance guideline. As a

check, the NRC staff performed limited confirmatory calculations using a simplified model of MNGP. The NRC staffs review assumed similar relay failure rates over a range of STIs and assumed that a failure of loop select logic would fail LPCI. The NRC staffs risk estimates are consistent with the licensees. Therefore, based on the previously successful time delay relay functional tests, the revised loop select time delay failure rates, and the assumed failure of the LPCI loop select function in the licensees PRA, the NRC staff concludes that the licensees proposed one-time extension does not invoke special circumstances that, if reviewed on a risk-informed basis, would warrant attaching conditions to or denying the proposed amendment.

The staff finds that the licensees proposed change does not reveal an unforseen hazard or a substantially greater potential for a known hazardous event to occur such that adequate protection would be in question. This conclusion is based on the very small increase in CDF and LERF (i.e., the increase in risk is within the RG 1.174 acceptance guidelines) for the proposed change. The estimated risk impacts are very small and should not significantly influence the overall results of the licensees deterministic analysis.

The NRC staff notes that the licensee did not indicate that the risk impacts played any role in its basis for the acceptability of this amendment. The licenses application did not address the key principles of risk-informed decisionmaking as presented in RG 1.174 and the NRC staff did not complete the full scope of risk review that would be required of a risk-informed application.

Although RG 1.174 risk acceptance guidelines were used in evaluating the licensees application, the NRC staffs review, by itself, does not provide a basis for approving the amendment based on the limited risk information available compared with a risk-informed application. In addition, the NRC staff did not evaluate traditional engineering insights such as maintenance recommendations, surveillance or maintenance history, setpoint methodology, or related topical reports (not specific to PRA analysis).

3.4 Summary of Review Based on the considerations discussed above, the NRC staff finds that the proposed surveillance test interval increase for the LPCI loop select time-delay relays is acceptable. The proposed change will eliminate unnecessary transients which could occur if the licensee were to be required to test the time-delay relays at power. Based on evaluation of recent logic system functional tests, the NRC staff concluded that the time-delay relays had functioned adequately.

The NRC staff concluded also that, in comparison to other delays in the LPCI injection sequence, possible drift in the time-delay relays would result in negligible changes in the timing of the LPCI injection sequence. In conclusion, the TSs may, on a one-time basis, be revised to defer Surveillance Requirements 3.3.5.1.2 and 3.3.5.1.4 for items 2.k, 2.l, and 2.m of Table 3.3.5.1-1 until entry into MODE 2 from the 2007 refueling outage.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Minnesota State official was notified of the proposed issuance of the amendment. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a surveillance requirement. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in

individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (71 FR 75995). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is 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.

Principal Contributor: B. Parks and C. Doutt Date: January 18, 2007

Monticello Nuclear Generating Plant cc:

Jonathan Rogoff, Esquire Commissioner Vice President, Counsel & Secretary Minnesota Department of Commerce Nuclear Management Company, LLC 85 7th Place East, Suite 500 700 First Street St. Paul, MN 55101-2198 Hudson, WI 54016 Manager - Environmental Protection Division U.S. Nuclear Regulatory Commission Minnesota Attorney Generals Office Resident Inspector's Office 445 Minnesota St., Suite 900 2807 W. County Road 75 St. Paul, MN 55101-2127 Monticello, MN 55362 Michael B. Sellman Manager, Nuclear Safety Assessment President and Chief Executive Officer Monticello Nuclear Generating Plant Nuclear Management Company, LLC Nuclear Management Company, LLC 700 First Street 2807 West County Road 75 Hudson, MI 54016 Monticello, MN 55362-9637 Nuclear Asset Manager Commissioner Xcel Energy, Inc.

Minnesota Pollution Control Agency 414 Nicollet Mall, R.S. 8 520 Lafayette Road Minneapolis, MN 55401 St. Paul, MN 55155-4194 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Commissioner Minnesota Department of Health 717 Delaware Street, S. E.

Minneapolis, MN 55440 Douglas M. Gruber, Auditor/Treasurer Wright County Government Center 10 NW Second Street Buffalo, MN 55313 November 2005