ML080230450
| ML080230450 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 01/11/2008 |
| From: | Mims D Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-05797-DCM/RJR | |
| Download: ML080230450 (15) | |
Text
/10 CFR 50.55a(f)(5) 10 CFR 50.55a(a)(3)
LAS A
subsidiary of Pinnacle West Capital Corporation Dwight C. Mims Mail Station 7605 Palo Verde Nuclear Vice President Tel. 623-393-5403 P.O. Box 52034 Generating Station Regulatory Affairs and Plant Improvement Fax 623-393-6077 Phoenix, Arizona 85072-2034 102-05797-DCM/RJR January 11, 2008 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, and 3 Docket Nos. STN 50-528/529/530 Resubmittal of the Third 10-Year Interval for the Pump and Valve Inservice Testing Relief Requests PRR-03, PRR-05 and VRR-01 By letter no.102-05732, dated August 13, 2007, Arizona Public Service (APS) submitted the revised Palo Verde Nuclear Generating Station (PVNGS) pump and valve inservice testing (IST) program for the third 10-year interval for Units 1, 2, and 3 pursuant to 10 CFR 50.55a(f)(5)(i). By letter no. 102-05771, dated November 28, 2007, APS submitted a response to a request for additional information to the August 13, 2007 submittal.
While reviewing the Relief Request submittals, typographical errors were found in Relief Requests PRR-03 and PRR-05 and as a result APS is resubmitting corrected copies of the Relief Requests. The typographical errors were applicable to the ISTB Code section numbers and descriptions. No technical errors were identified. In addition, the specific applicable ISTC Code requirements were added to Relief Request VRR-01.
This letter contains no new commitments. If you have any questions about this change, please telephone Glenn A. Michael at (623) 393-5750.
Sincerely, DCM/GAM/RJR/
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway 0 Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Response to the Request for Additional Information Regarding Third 10-Year Interval Pump and Valve Inservice Testing Program Page 2 Enclosure APS's Resubmittal of the Third 10-Year Interval Pump and Valve Inservice Testing Program Relief Requests PRR-03, PRR-05 and VRR-01 cc:
E. E. Collins, Jr.
M. T. Markley G. G. Warnick NRC Region IV Regional Administrator NRC NRR Project Manager NRC Senior Resident Inspector for PVNGS
Enclosure APS's Resubmittal of the Third 10-Year Interval Pump and Valve Inservice Testing Program V*elief Requests PRR-03, PRR-05 and VRR-01
PUMPRELIEF REQUEST PRR-03 Relief Request In Accordance with 10 CFR 50.55a(f)(5)(iii)
-- Inservice Testing Impracticality -
LPSI Pump Flow Rate Measurement ASME Components Affected Pump ID Pump Description Code Class Pump Group SIA-PO1 Low Pressure Safety Injection 2
A (LPSI) Pump SIB-PO1 Low Pressure Safety Injection 2
A (LPSI) Pump Component/System Function:
LPSI pumps SIA-PO1 and SIB-P01 provide low-pressure coolant injection of borated water into the reactor coolant system under accident conditions. They also provide shutdown cooling flow post-accident and during normal reactor startup and shutdown.
Applicable Code Edition and Addenda
ASME OM Code 2001 Edition w/2003 Addenda Applicable Code Requirement(s):
ISTB-3300, "Reference Values," ISTB-3300(e)(2), "Reference values shall be established within +/- 20% of pump design flow for the Group A and Group B tests, if practicable. If not practicable, the reference point flow rate shall be established at the highest practical flow rate."
ISTB-5121, "Group A Test Procedure," "Group A tests shall be conducted with the pump operating at a specified reference point. The test parameters shown in Table ISTB-3000-1 shall be determined and recorded as required by this paragraph."
ISTB-5121(b), "The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure shall then be determined and compared to its reference value. Alternatively, the flow rate shall be varied until the differential pressure equals the reference point and the flow rate determined and compared to the reference flow rate value."
ISTB-5121(c), "Where it is not practical to vary system resistance, flow rate and pressure shall be determined and compared to their respective reference values."
Page 1
- i*'*
PUMP'RELIEF REQUEST PRR-03 Impracticality of Compliance:
The Code requires the Group A reference point flow rate to be established at the highest practical flow rate and operate the pump at a specified reference point (i.e., fix the flow to a specified value). It is impractical to meet this requirement since this is a fixed resistance recirculation path of approximately 180 gpm with limited capability permanent plant flow instrumentation. The installed instrumentation is a 0-5000 gpm ultrasonic flowmeter with +/- 5% accuracy and does not meet the 2% instrument requirements of Table ISTB-3500-1 for pump testing. The use of an ultrasonic flowmeter with 2% accuracy was evaluated and determined impractical due to the difficulty in establishing an application specific 2% calibration on the SI mini-flow piping.
To establish the fixed resistance the minimum flow recirculation line contains a flow orifice and a normally open motor-operated valve and solenoid isolation valve. Allowing the flow to remain fixed by the orifice resistance increases the potential for repeatable test results and degradation monitoring rather than attempting to change the resistance based on ultrasonic flowmeter readout fluctuations. When the pump operates on minimum flow recirculation, the specified reference point is essentially achieved by the fixed resistance. With this understanding, there is little value added in replacing the existing 0-5000 gpm, +/- 5% ultrasonic flowmeter, or adding instrumentation that meets IST-3510 requirements. The fixed resistance methodology is repeatable from test to test and accomplishes the same result as if flow were being measured and recorded.
Burden Caused by Compliance:
During normal plant operation, the LPSI pumps cannot develop sufficient discharge pressure to overcome RCS pressure and allow flow through the safety injection headers. Thus, during quarterly testing, LPSI flow is routed through a minimum flow recirculation line to the refueling water tanks. The minimum-flow recirculation flowpath is a fixed resistance circuit containing a flow-limiting orifice capable of passing only a small fraction (approx. 180 gpm) of the design flow (4200 gpm). The permanent plant 0-5000 gpm, +/- 5% accuracy, flow instrumentation (permanently mounted ultrasonic flowmeter) has only limited capability, and its accuracy does not meet Table ISTB-3500-1 flow rate 2% accuracy requirements. The use of an ultrasonic flowmeter with 2%
accuracy was evaluated and determined to be impractical due to the difficulty in establishing an application specific 2% calibration on the SI mini-flow piping.
The LPSI pumps are categorized as Group A since they are normally used to provide shutdown cooling flow during shutdown operations, and occasionally for recirculating the refueling water tank when the unit is at power. Little degradation is expected during plant operation. Thus, the alternate testing will adequately monitor these pumps to ensure continued operability and availability for accident mitigation.
Modifying the minimum flow recirculation line to provide flow indication to meet the +/- 2%
accuracy requirement as specified in Table ISTB-3500-1 adds little value since the flow is fixed and differential pressure is used to monitor degradation.
Page 2
PUMP RELIEF REQUEST PRR-03 Proposed Alternative and Basis for Use:
During plant operation, quarterly Group A pump testing for pumps SIA-PO1 and SIB-PO1 shall be conducted at mini-flow conditions using the minimum flow recirculation line fixed resistance of approximately 180 gpm to establish the specified reference point.
Subsection ISTB, ISTB-51 00(b)(1) allows the use of bypass test loops to be used for Group A tests. The flow rate through the loop is established at the highest practical flow rate of approximately 180 gpm in accordance with ISTB-3300(e)(2). Flow rate will not be measured or recorded. To monitor for degradation, pump differential pressure shall be determined and compared to its reference value and the associated range as specified in Table ISTB-5100-1.
Pumps SIA-PO1 and SIB-PO1 will be comprehensively tested in accordance with ISTB-5123, "Comprehensive Test Procedure," on a biennial (2-year) frequency as specified in Table ISTB-3400-1.
Pumps SIA-PO1 and SIB-P01 are infrequently used pumps. Little degradation is expected during plant power operation when the pumps are idle except for limited operations and testing. Testing the pumps within +/- 20% of design flow on a 2-year frequency provides additional information regarding the condition of the pumps.
Vibration measurements will be performed quarterly in accordance with ISTB-3540.
==
Conclusion:==
10 CFR50.55a(f)(5)(iii) states:
"If the licensee has determined that conformance with certain code requirements is impractical for its facility, the licensee shall notify the Commission and submit, as specified in § 50.4 information to support the determination."
The information provided in this request supports the determination that it is impractical to meet the Code requirements to establish the Group A reference point flow rate at the highest practical flow rate and operate the pump at a specified reference point (i.e., fix the flow to a specified value) since this is a fixed resistance recirculation path with limited capability permanent plant flow instrumentation.
Duration of Proposed Alternative:
The proposed alternative identified in this 10 CFR 50.55a Request shall be utilized during the third 10-year IST Interval.
Page 3
PUMP RELIEF REQUEST PRR-03 Precedents:
Complies with NRC GL 89-04, Position 9. A similar 10 CFR 50.55a Request (PRR-05) was previously authorized for Palo Verde pursuant to 10 CFR 50.55a(f)(6)(i) for Interval 2 per NRC Safety Evaluation dated July 8, 1999. (TAC NOS. MA0757, MA0758 and MA0759) (ADAMS Accession No. 9907150128)
Page 4
PUMP RELIEF REQUEST PRR-05 Relief Request In Accordance with 10 CFR 50.55a(f)(5)(iii)
-- Inservice Testing Impracticality -
Containment Spray Pump Flow Rate Measurement ASME Components Affected Pump ID Pump Description Code Class Pump Group SIA-P03 Containment Spray (CS) Pump 2
A SIB-P03 Containment Spray (CS) Pump 2
A Component/System Function:
CS pumps SIA-P03 and SIB-P03 deliver borated water to the containment spray headers, providing containment cooling and pressure control during accident conditions.
The CS pumps can also be lined up to provide flow for shutdown cooling.
Applicable Code Edition and Addenda
ASME OM Code 2001 Edition w/2003 Addenda Applicable Code Requirement(s):
ISTB-3300, "Reference Values," ISTB-3300(e)(2), "Reference values shall be established within +/- 20% of pump design flow for the Group A and Group B tests, if practicable. If not practicable, the reference point flow rate shall be established at the highest practical flow rate."
ISTB-5121, "Group A Test Procedure," "Group A tests shall be conducted with the pump operating at a specified reference point. The test parameters shown in Table ISTB-3000-1 shall be determined and recorded as required by this paragraph."
ISTB-5121(b), "The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure shall then be determined and compared to its reference value. Alternatively, the flow rate shall be varied until the differential pressure equals the reference point and the flow rate determined and compared to the reference flow rate value."
ISTB-5121(c), "Where it is not practical to vary system resistance, flow rate and pressure shall be determined and compared to their respective reference values."
Page 1
PUMP RELIEF REQUEST PRR-05 Impracticality of Compliance:
The Code requires the Group A reference point flow rate to be established at the highest practical flow rate and operate the pump at a specified reference point (i.e., fix the flow to a specified value). It is impractical to meet this requirement since this is a fixed resistance recirculation path of approximately 190 gpm with limited capability permanent plant flow instrumentation. The installed instrumentation is a 0-5000 gpm ultrasonic flowmeter with +/- 5% accuracy and does not meet the 2% instrument requirements of Table ISTB-3500-1 for pump testing. The use of an ultrasonic flowmeter with 2% accuracy was evaluated and determined impractical due to the difficulty in establishing an application specific 2% calibration on the SI mini-flow piping.
To establish the fixed resistance the minimum flow recirculation line contains a flow orifice and a normally open motor-operated valve and solenoid isolation valve. Allowing the flow to remain fixed by the orifice resistance increases the potential for repeatable test results and degradation monitoring rather than attempting to change the resistance based on ultrasonic flowmeter readout fluctuations. When the pump operates on minimum flow recirculation, the specified reference point is essentially achieved by the fixed resistance. With this understanding, there is little value added in replacing the existing 0-5000 gpm, +/- 5% ultrasonic flowmeter, or adding instrumentation that meets IST-3510 requirements. The fixed resistance methodology is repeatable from test to test and accomplishes the same result as if flow were being measured and recorded.
Burden Caused by Compliance:
Modifying the minimum flow recirculation line to provide flow indication to meet the +/- 2%
accuracy requirement as specified in Table ISTB-3500-1 adds little value since the flow is fixed at approximately 190 gpm and differential pressure is used to monitor degradation. The permanent plant 0-5000 gpm, +/- 5% accuracy, flow instrumentation (permanently mounted ultrasonic flowmeter) has only limited capability, and its accuracy does not meet Table ISTB-3500-1 flow rate 2% accuracy requirements. The use of an ultrasonic flowmeter with 2% accuracy was evaluated and determined impractical due to the difficulty in establishing an application specific 2% calibration on the SI mini-flow piping.
The normal containment spray flow path cannot be used for testing the CS pumps without spraying down the inside of the containment building and risking damage to important equipment. The RCS injection portion of the shutdown cooling flow path cannot be used for testing during plant operation because the CS pumps are unable to develop sufficient discharge pressure to overcome RCS pressure.
The minimum-flow recirculation flowpath is a fixed resistance circuit containing a flow-limiting orifice capable of passing only a small fraction (approx. 190 gpm) of the design flow (3890 gpm). The permanent plant 0-5000 gpm, +/- 5% accuracy, flow instrumentation (permanently mounted ultrasonic flowmeter) has only limited capability, and its accuracy does not meet Table ISTB-3500-1 flow rate 2% accuracy requirements. A larger recirculation flowpath is available; however, this requires an Page 2
PUMP RELIEF REQUEST PRR-05 alternate line up and the same limited capability flow instrument exists in this portion of the recirculation line.
The larger recirculation flowpath is capable of carrying higher flow, but routine surveillance testing at less than the full flow reference value is not practical because of the pump rumble range (1800-2800 gpm). Testing in or near the rumble range is not practical because of the potential for equipment damage. Testing at flow rates above the rumble range (> 2800 gpm) is not practical because flow velocities in the recirculation piping would exceed the design criteria.
The CS pumps are categorized as Group A since they are normally used to provide shutdown cooling flow during shutdown operations. Little degradation is expected during plant operation. Thus, the alternate testing will adequately monitor these pumps to ensure continued operability and availability for accident mitigation.
Proposed Alternative and Basis for Use:
During plant operation, quarterly Group A pump testing for pumps SIA-P03 and SIB-P03 shall be conducted at mini-flow conditions using the minimum flow recirculation line fixed resistance of approximately 190 gpm to establish the specified reference point.
ISTB-5100(b)(1) allows the use of bypass test loops to be used for Group A tests. The flow rate through the loop is established at the highest practical flow rate of approximately 190 gpm in accordance with ISTB-3300(e)(2). Flow rate will not be measured or recorded. To monitor for degradation, pump differential pressure shall be determined and compared to its reference vaiue and the associated range as specified in Table ISTB-51 00-1.
Pumps SIA-P03 and SIB-P03 wil! be comprehensively tested in accordance with ISTB-5223, "Comprehensive Test Procedure," on a biennial (2-year) frequency as specified in Table ISTB-3400-1.
Pumps SIA-P03 and SIB-P03 are infrequently used pumps. Little degradation is expected during plant power operation when the pumps are idle except for limited operations and testing. Testing the pumps within +/- 20% of design flow on a 2-year frequency provides additional information regarding the condition of the pumps.
Vibration measurements will be performed quarterly in accordance with ISTB-3540.
==
Conclusion:==
10 CFR50.55a(f)(5)(iii) states:
"If the licensee has determined that conformance with certain code requirements is impractical for its facility, the licensee shall notify the Commission and submit, as specified in § 50.4 information to support the determination."
Page 3
PUMP RELIEF REQUEST PRR-05 The information provided in this request supports the determination that it is impractical to meet the Code requirements to establish the Group A reference point flow rate at the highest practical flow rate and operate the pump at a specified reference point (i.e., fix the flow to a specified value) since this is a fixed resistance recirculation path with limited capability permanent plant flow instrumentation.
Duration of Proposed Alternative:
The proposed alternative identified in this 10 CFR 50.55a Request shall be utilized during the third 10-year IST Interval.
Precedents:
Complies with NRC GL 89-04, Position 9. A similar 10 CFR 50.55a Request (PRR-1 1) was previously authorized for Palo Verde pursuant to 10 CFR 50.55a(f)(6)(i) for Interval 2 per NRC Safety Evaluation dated July 3, 1999. (TAC NOS. MA0757, MA0758 and MA0759) (ADAMS Accession No. 9907150128)
Page 4
VALVE RELIEF REQUEST VRR 01 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)
On the basis that the proposed alternative provides an acceptable level of quality and safety.
Code Case OMN MOV Exercising and Stroke Timing Component(s) Affected:
Motor-operated valve assemblies currently included in the Palo Verde Nuclear Generating Station (PVNGS) Motor-Operated Valve (MOV) Program Component/System Function: Various
Applicable Code Edition and Addenda
ASME OM Code 2001 Edition w/2003 Addenda Applicable Code Requirement(s):
ISTA-3130, "Application of Codes Cases", ISTA-3130(b) states, Code Cases shall be applicable to the edition and addenda specified in the test plan.
Subsection ISTC "Inservice Testing of Valves in Light-Water Reactor Nuclear Power Plants.
ISTC-3100, "Preservice Testing" ISTC-3310, "Effects of Valve Repair, Replacement, or Maintenance on Reference Values" ISTC-3700, "Position Verification Testing" ISTC-5121, "Valve Stroke Testing" ISTC-5122, "Stroke Test Acceptance Criteria" ISTC-5123, "Stroke test Corrective Action" Regulatory Guide 1.192, Operation and Maintenance Code Case Acceptability, ASME OM Code, dated June 2003 states that licensees may use Code Case OMN-1, "Alternative Rules for Preservice and Inservice Testing of Certain Electric Motor-Operated Valve Assemblies in Light-Water Reactor Power Plants," Revision 0, in lieu of the provisions for stroke-time testing in Subsection ISTC of the 1995 Edition up to and Page 1
VALVE RELIEF REQUEST VRR 01 including the 2000 Addenda of the ASME OM Code when applied in conjunction with the provisions for leakage rate testing in, as applicable, ISTC 4.3 (1995 Edition with the 1996 and 1997 Addenda) and ISTC-3600 (1998 Edition with the 1999 and 2000 Addenda). In addition, licensees who continue to implement Section X1 of the ASME BPV Code as their Code of Record may use OMN-1 in lieu of the provisions for stroke-time testing specified in Paragraph 4.2.1 of ASME/ANSI OM Part 10 as required by 10 CFR 50.55a(b)(2)(vii) subject to the conditions in this Regulatory Guide (RG) 1.192.
Licensees who choose to apply OMN-1 are required to apply all its provisions.
The relevant provisions are as follows:
(1) The adequacy of the diagnostic test interval for each motor-operated valve (MOV) must be evaluated and adjusted as necessary, but not later than 5 years or three refueling outages (whichever is longer) from initial implementation of OMN-1.
(2) When extending exercise test intervals for high risk MOVs beyond a quarterly frequency, licensees must ensure that the potential increase in Core Damage Frequency (CDF) and risk associated with the extension is small and consistent with the intent of the Commission's Safety Goal Policy Statement.
(3) When applying risk insights as part of the implementation of OMN-1, licensees must categorize MOVs according to their safety significance using the methodology described in Code Case OMN-3, "Requirements for Safety Significance Categorization of Components Using Risk Insights for Inservice Testing of LWR Power Plants," with the conditions discussed in RG 1.192 or use other MOV risk ranking methodologies accepted by the NRC on a plant specific or industry-wide basis with the conditions in the applicable safety evaluations.
Reason for Request
Code Case OMN-1, Revision 0 provides alternative rules to those of OM Code, Subsection ISTC, for preservice and inservice testing to assess the operational readiness of certain electric motor-operated valve assemblies in light-water reactor power plants. However, RG 1.192 has not yet extended its use to the 2001 Edition w/2003 Addenda of the OM Code which is the basis for the planned third 10-year IST program at Palo Verde.
Proposed Alternatives and Basis for Use:
In lieu of the provisions for MOV testing in Subsection ISTC of the 2001 Edition w/2003 Addenda of the ASME OM Code listed in the Applicable Code Requirements section of this request, (ISTC Sections 3100, 3310, 3700, 5121, 5122 and 5123 that are associated with testing Motor-Operated Valves) APS requests relief for the continued use of ASME Code Case OMN-1, Revision 0.
Page 2
VALVE RELIEF REQUEST VRR 01 Pursuant to ASME Code Case OMN-1, Revision 0 and the guidelines provided in NUREG-1482, Revision 1, Section 4.2.5, PVNGS proposes to continue implementation of Code Case OMN-1 in lieu of the stroke-time provisions specified in ISTC-5120 for MOVs. Code Case OMN-1 has been determined by the NRC to provide an acceptable level of quality and safety when implemented in conjunction with the conditions imposed in RG 1.192.
Code Case OMN-1, R 0, should be considered acceptable for use with OM Code-2001 Edition w/2003 Addenda as the Code of record. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), PVNGS requests relief from the specific ISTC Code requirements identified in this relief request.
==
Conclusion:==
10 CFR 50.55a(a)(3) states:
"Proposed alternatives to the requirements of paragraphs (c), (d), (e), (f), (g), and (h) of this section or portions thereof may be used when authorizar! by the Director of the Office of Nuclear Reactor Regulation. The applicant shall demonstrate that:
(i)The proposed alternatives would provide an acceptable level of quality and safety, or (ii)Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety."
The continued use of ASME Code Case OMN-1, Revision 0, as discussed in this relief request provides an acceptable level of quality and safety. Therefore, APS requests that the proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(i).
Duration of Proposed Alternatives:
The proposed alternative identified in this relief request shall be utilized during the third 10-year IST interval.
Precedents:
A similar 10 CFR 50.55a Request (VRR-12) was previously authorized for Palo Verde pursuant to 10 CFR 50.55a(a)(3)(i) for interval 2 per NRC Safety Evaluation dated July 8,1999. (TAC NOS. MA0757, MA0758 and MA0759) (ADAMS Accession No.
9907150128)
References:
NUREG-1482, Revision 1, Section 4.2.5, "Alternatives to Stroke-Time Testing" Page 3
II,,
VALVE RELIEF REQUEST VRR 01 Regulatory Guide 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code", Table 2, "Conditionally Acceptable OM Code Cases" OM Code-2001 Edition w/2003 Addenda, Paragraph ISTC-5120, "Motor Operated Valves" OM Code-2001 Edition w/2003 Addenda, Paragraph ISTA-3130, "Application of Code Cases" Code Case OMN-1, Revision 0, "Alternative Rules for Preservice and Inservice Testing of Certain Electric Motor-Operated Valve Assemblies in LWR Power Plants" Page 4