RS-03-079, Request for Amendment to Technical Specifications, Surveillance Requirement 3.7.7.1 for Turbine Bypass Valve Testing

Request for Amendment to Technical Specifications, Surveillance Requirement 3.7.7.1 for Turbine Bypass Valve Testing

ML031480554
Person / Time
Site:	LaSalle
Issue date:	05/19/2003
From:	Jury K Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NUREG-1434, RS-03-079
Download: ML031480554 (14)

Text

Exelon GeneTation www.exeloncorp.com ExeNuclear sn 4300 Winfield Road Warrenville, IL 60555 10 CFR 50.90 RS-03-079 May 19, 2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374

Subject:

Request for Amendment to Technical Specifications Surveillance Requirement 3.7.7.1 for Turbine Bypass Valve Testing In accordance with 10 CFR 50.90, Exelon Generation Company (EGC), LLC, hereby requests the following amendment to Appendix A, Technical Specifications (TS), of Facility Operating License Nos. NPF-1 1 and NPF-18. Specifically, the proposed change will decrease the frequency associated with Surveillance Requirement (SR) 3.7.7.1 for Turbine Bypass Valve (BPVs) testing, from 7 to 31 days. The proposed change is consistent with the testing frequency contained in NUREG -1434, "Standard Technical Specifications General Electric Plants, BWR/6," Revision 2, dated June 2001, for BPV testing.

The 7-day frequency associated with SR 3.7.7.1 was established in the LaSalle County Station (LSCS) TS during conversion to Improved Technical Specifications (ITS) format due to the testing frequency contained in the LSCS custom TS and the difficulties experienced with other Electro-Hydraulic Control (EHC) system valves to consistently pass their surveillance tests.

LSCS has recently re-evaluated the performance of these valves and has determined that the current performance of these valves supports decreasing the testing frequency of the BPVs from 7 to 31 days.

The information supporting the proposed TS change is subdivided as follows.

Attachment 1 is the notarized affidavit.

Attachment 2 provides our evaluation supporting the proposed change.

Attachment 3 contains a copy of the marked up TS page.

Attachment 4 provides the retyped TS page and Bases page for information only.

p-fro 0 I

May 19, 2003 U. S. Nuclear Regulatory Commission Page 2 The proposed TS change has been reviewed by the LaSalle County Station Plant Operations Review Committee (PORC) and approved by the Nuclear Safety Review Board (NSRB) in accordance with the Quality Assurance Program.

EGC is notifying the State of Illinois of this application for amendment by transmitting a copy of this letter and its attachments to the designated State Official.

We request approval of the proposed change by June 1, 2004 with an implementation period of 60 days.

Should you have any questions concerning this submittal, please contact Mr. T. W. Simpkin at (630) 657-2821.

Sincerely, gooL~- Keith R. ury Director-Licensing Mid-West Regional Operating Group Attachments:

Attachment 1. Affidavit Attachment 2. Evaluation of Proposed Change Attachment 3. Markup of Proposed Technical Specification Page Change Attachment 4. Retyped Pages for Technical Specification Change and Bases Change (for information only) cc: Regional Administrator - NRC Region Il NRC Project Manager - NRR NRC Senior Resident Inspector - LaSalle County Station Office of Nuclear Facility Safety - Illinois Department of Nuclear Safety

ATTACHMENT I Affidavit STATE OF ILLINOIS )

COUNTY OF DUPAGE )

IN THE MATTER OF: )

EXELON GENERATION COMPANY (EGC), LLC ) Docket Numbers LASALLE COUNTY STATION - UNIT I and UNIT 2 ) 50-373 and 50-374

SUBJECT:

Request for Amendment to Technical Specifications Surveillance Requirement 3.7.7.1 for Turbine Bypass Valve Testing AFFIDAVIT I affirm that the content of this transmittal is true and correct to the best of my knowledge, information, and belief.

c(2..

T. W. SimplCin Manager-Licensing Mid-West Regional Operating Group Subscribed and sworn to before me, a Notary Public in and for the State above named, this / day of

) , 2003 Notary Public C OFFIC-1 ANESE:

NOTARY PUBl: .'IS MYCOMMISS0Q0N.. _ 15

ATTACHMENT 2 Evaluation of Proposed Change Page 1 of 6

2.0 DESCRIPTION

OF PROPOSED AMENDMENT

3.0 BACKGROUND

4.0 REGULATORY REQUIREMENTS & GUIDANCE

6.0 REGULATORY ANALYSIS

7.0 NO SIGNIFICANT HAZARDS CONSIDERATION (NSHC)

8.0 ENVIRONMENTAL CONSIDERATION

9.0 PRECEDENT

ATTACHMENT 2 Evaluation of Proposed Change Page 2 of 6

1.0 INTRODUCTION

In accordance with 10 CFR 50.90, Exelon Generation Company (EGC), LLC, hereby requests the following amendment to Appendix A, Technical Specifications (TS), of Facility Operating License Nos. NPF-1 1 and NPF-18. Specifically, the proposed change will decrease the frequency associated with Surveillance Requirement (SR) 3.7.7.1 for Turbine Bypass Valve (BPVs) testing from 7 to 31 days. The proposed change is consistent with the testing frequency contained in NUREG -1434, "Standard Technical Specifications General Electric Plants, BWR/6," Revision 2, dated June 2001, for BPV testing.

The 7-day frequency associated with SR 3.7.7.1 was established in the LaSalle County Station (LSCS) TS during conversion to Improved Technical Specifications (ITS) format due to the testing frequency contained in the LSCS custom TS and the difficulties experienced with other Electro-Hydraulic Control (EHC) system valves to consistently pass their surveillance tests. LSCS has recently re-evaluated the performance of these valves and has determined that the current performance of these valves supports decreasing the testing frequency of the BPVs from 7 to 31 days.

2.0 DESCRIPTION

OF PROPOSED AMENDMENT The proposed change decreases the frequency associated with SR 3.7.7.1 for BPVs testing from 7 to 31 days.

3.0 BACKGROUND

The Main Turbine Bypass System is designed to control steam pressure when reactor steam generation exceeds turbine requirements during unit startup, sudden load reduction, and cooldown. It allows excess steam flow from the reactor to the condenser without going through the turbine. The bypass capacity of the system is approximately 25% of the Nuclear Steam Supply System rated steam flow. Sudden load reductions within the capacity of the steam bypass can be accommodated without reactor scram.

The Main Turbine Bypass System consists of five valves mounted on a valve manifold connected to the main steam lines between the main steam isolation valves and the main turbine stop valves. Each of these BPVs is sequentially operated by hydraulic cylinders. The BPVs are controlled by the pressure regulation function of the Turbine EHC System, as discussed in the Updated Final Safety Analysis Report (UFSAR),

Section 7.7.5.2. The BPVs are normally closed, and the pressure regulator controls the turbine control valves, directing all steam flow to the turbine. If the speed governor or the load limiter restricts steam flow to the turbine, the pressure regulator controls the system pressure by opening the BPVs. When the BPVs open, the steam flows from the -

BPV outlet manifold, through connecting piping, to the pressure breakdown assemblies, where a series of orifices are used to further reduce the steam pressure before the steam enters the condenser.

The 7-day frequency associated with SR 3.7.7.1 was established in the LSCS TS during

ATTACHMENT 2 Evaluation of Proposed Change Page 3 of 6 conversion to ITS format due to the testing frequency contained in the LSCS custom TS and the previous performance of other EHC system valves to consistently pass their surveillance tests.

EHC fluid at LSCS has consistently met or exceeded vendor and industry recommendations for fluid cleanliness. Even though the fluid samples continuously indicated the fluid exceeded these requirements for cleanliness, LSCS experienced approximately 30 solenoid failures during Turbine Control Valve (CV), Stop Valve (SV),

and Combined Intermediate Valve (CIV) testing between 1999 and 2001. These failures were primarily due to solenoid valve sticking caused by degraded EHC fluid in the hydraulic lines to the solenoids. TS and vendor testing requires the SVs and CVs to be cycled on a quarterly frequency. Due to the failures, SVs were tested on a weekly frequency and CVs were tested monthly. Even with increased frequency testing, failures occurred on CVs and SVs. CVs are tested whenever unit load is reduced below 50%

and solenoid failures also occurred in these valves between 1999 and 2001. BPVs are tested weekly based on TS requirements and no BPV testing failures were experienced during the 1999 to 2001 timeframe. This may have been due to the fact that the BPVs use a different, more robust solenoid valve than those on other EHC system valves.

However, even though no BPV failures occurred during testing, LSCS was not in favor of extending the TS required testing frequency of the bypass valves from 7 to 31 days at the time of the ITS conversion because of the poor hydraulic system performance exhibited by the SV, CV, and CIV failures.

Since the conversion to ITS, LSCS performed a root cause investigation into the EHC system valve testing failures. The root cause identified heat degradation of the EHC fluid as the cause of the fluid degradation and poor turbine valve solenoid performance.

As a result of this root cause evaluation, corrective actions were taken on both Unit I and Unit 2 in early 2002. These corrective actions included; a chemical flush of the EHC system hydraulic piping and components, insulation of all identified heat sources near EHC system piping and components, replacement of the standard EHC fluid, which was a natural synthetic fluid blend, with an all synthetic EHC fluid that is less susceptible to heat degradation, and replacement of all solenoids with new solenoids. Additionally, in mid-2002 an electrostatic fluid purification system was placed into service on both units to remove heat degradation products from EHC fluid. The corrective actions taken have resulted in significant improvements in hydraulic system performance. Beginning in January 2002, the testing frequency of SVs and CVs was extended to quarterly consistent with the TS and vendor requirements. CVs continued to be tested whenever unit load was reduced below 50%, with the time between these tests being as long as 6 months. Since the system upgrades were made, there have been no failures of solenoids on CVs, SVs; or CIVs. In addition, there continues to be no BPV test failures.

4.0 REGULATORY REQUIREMENTS & GUIDANCE 10 CFR 50.36(c)(2)(ii)(c), "Criterion 3," requires that a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier must be included in a licensee's TS.

ATTACHMENT 2 Evaluation of Proposed Change Page 4 of 6

5.0 TECHNICAL ANALYSIS

5.1 Design Bases Cycling each BPV through one complete cycle of full travel demonstrates that the valves are mechanically OPERABLE and will function when required. The 7-day frequency associated with SR 3.7.7.1 was conservatively established in the LSCS TS during conversion to ITS format due to the previous performance of other EHC system valves to consistently pass their surveillance tests during the 1999 to 2001 timeframe. There were no BPV testing failures experienced during the 1999 to 2001 timeframe and there continues to be no BPV test failures. Based on current EHC hydraulic system performance and the testing frequency contained in NUREG -1434, LSCS believes decreasing the test frequency for BPVs from 7 to 31 days is justified.

5.2 Risk Information This submittal is not based on risk-informed decision making.

6.0 REGULATORY ANALYSIS

The Main Turbine Bypass System is required to be operable to limit peak pressure in the main steam lines and maintain reactor pressure within acceptable limits during events that cause rapid pressurization, such that the Safety Limit Minimum Critical Power Ratio (MCPR) is not exceeded. An operable Main Turbine Bypass System requires the BPVs to open in response to increasing main steam line pressure. Therefore, BPV testing must be included in LSCS TS in accordance with 10 CFR 50.36(c)(2)(ii)(c).

7.0 NO SIGNIFICANT HAZARDS CONSIDERATION EGC has evaluated the proposed change to the TS for LSCS, Unit 1 and Unit 2, and has determined that the proposed change does not involve a significant hazards consideration and is providing the following information to support a finding of no significant hazards consideration.

Does the change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed change will decrease the frequency associated with Surveillance Requirement (SR) 3.7.7.1 for turbine bypass valve (BPV) testing from 7 to 31 days. The proposed change is consistent with the testing frequency contained in NUREG -1434, "Standard Technical Specifications General Electric Plants, BWR16," Revision 2, dated June 2001, for BPV testing. The performance of BPV surveillance testing is not a precursor to any accident previously evaluated.

ATTACHMENT 2 Evaluation of Proposed Change Page 5 of 6 Thus, the proposed change does not have any effect on the probability of an accident previously evaluated.

The Main Turbine Bypass System is required to be operable to limit peak pressure in the main steam lines and maintain reactor pressure within acceptable limits during events that cause rapid pressurization, such that the Safety Limit Minimum Critical Power Ratio (MCPR) is not exceeded. An operable Main Turbine Bypass System requires the BPVs to open in response to increasing main steam line pressure. The performance of BPVs surveillance testing provides assurance that the valves will operate as assumed in accidents previously evaluated. Thus, the radiological consequences of any accident previously evaluated are not increased.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Does the change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change does not affect the control parameters governing unit operation and does not introduce any new equipment, modes of system operation or failure mechanisms. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

Does the change involve a significant reduction in a margin of safety?

Response: No The proposed change will decrease the frequency associated with SR 3.7.7.1 for BPV testing from 7 to 31 days. The proposed change is consistent with the BPV testing frequency contained in NUREG -1433, Revision 2, and does not effect the design parameters or the setpoints associated with BPV operation. Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Based upon the above, EGC concludes that the proposed amendment presents no 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.

ATTACHMENT 2 Evaluation of Proposed Change Page 6 of 6

8.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion 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 with the proposed amendment.

9.0 PRECEDENT The proposed amendment incorporates into the LCSC TS a change to SR 3.7.7.1 that is consistent with the wording and intent of NUREG-1434, Rev. 2.

ATTACHMENT 3 MARKUP OF PROPOSED TECHNICAL SPECIFICATION PAGE CHANGE Revised TS Page

Main Turbine Bypass System 3.7.7 3.7 PLANT SYSTEMS 3.7.7 Main Turbine Bypass System LCO 3.7.7 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)." limits for an inoperable Main Turbine Bypass System, as specified in the COLR. are made applicable.

APPLICABILITY: THERMAL POWER 25% RTP.

ACTIONS -. .

CONDITION REOUIRED ACTION COMPLETION TIME A. Requirements of the A.1 Satisfy the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> LCO not met. requirements of the LCO.

B. Required Action and B.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 25% RTP.

Time not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.7.1 Verify one complete cycle of each main days turbine bypass valve.

(continued)

LaSalle 1 and 2 3.7. 7-1 Amendment-No. 147/133

ATTACHMENT 4 RETYPED PAGE FOR TECHNICAL SPECIFICATION CHANGE Retyped TS Page

Main Turbine Bypass System 3.7.7 3.7 PLANT SYSTEMS 3.7.7 Main Turbine Bypass System LCO 3.7.7 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," limits for an inoperable Main Turbine Bypass System, as specified in the COLR, are made applicable.

APPLICABILITY: THERMAL POWER 25% RTP.

ACTIONS -

CONDITION REQUIRED ACTION COMPLETION TIME A. Requirements of the A.1 Satisfy the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> LCO not met. requirements of the LCO.

B. Required Action and B.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 25% RTP.

Time not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.7.1 Verify one complete cycle of each main 31 days I turbine bypass valve.

(continued)

LaSalle 1 and 2 3.7. 7-1 Amendment No.

Bypass System Main Turbine Main Turbine Bypass-System B 3.7.7 BASES ACTIONS B.1 (continued)

If the Main Turbine Bypass System cannot be restored to OPERABLE status and the MCPR limits for an inoperable Main Turbine Bypass System are not applied, THERMAL POWER must be reduced to < 25% RTP. As discussed in the Applicability section, operation at < 25% RTP results in sufficient margin to the required limits, and the Main Turbine Bypass System is not required to protect fuel integrity during the turbine trip, turbine generator load rejection, and feedwater controller failure maximum demand transients. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time is reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

SURVEILLANCE SR 3.7.7.1 REQUIREMENTS Cycling each main turbine bypass valve through one complete cycle of full travel demonstrates that the valves are mechanically OPERABLE and will function when required. The 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions. Operating experience has shown that these components usually pass the SR when performed at the 31 day frequency. Therefore, the Frequency is acceptable from a reliability standpoint.

SR 3.7.7.2 The Main Turbine Bypass System is required to actuate automatically to perform its design function. This SR demonstrates that, with the required simulated system initiation signals, the valves will actuate to their required position. The 24 month Frequency is based on the need to perform this Surveillance under conditions that apply during a unit outage and because of the potential for an unplanned transient if the Surveillance were performed with the reactor at power. Operating experience has shown that these components usually pass the SR when performed at the 24 month-Frequency, which is based on the refueling cycle. Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

(continued)

LaSalle 1 and 2 B 3.7.7-3 Revi si on