ML14329A185

Relief Requests for Fifth 10-Year Inservice Testing Program Interval (Tac Nos. MF3928 and MF3929)

ML14329A185
Person / Time
Site:	Prairie Island
Issue date:	12/05/2014
From:	David Pelton Plant Licensing Branch III
To:	Davison K Northern States Power Co
Wall S
References
TAC MF3928, TAC MF3929
Download: ML14329A185 (23)

Text

Mr. Kevin K. Davison Site Vice President UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 5, 2014 Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota 1717 Wakonade Drive East Welch, MN 55089

SUBJECT:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2-RELIEF REQUESTS FOR FIFTH 10-YEAR INSERVICE TESTING PROGRAM INTERVAL (TAC NOS. MF3928 and MF3929)

Dear Mr. Davison:

By letter dated April 9, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14099A283), as supplemented by letter dated September 19, 2014 (ADAMS Accession No. ML14265A090), Northern States Power Company-Minnesota (NSPM, the licensee), doing business as Xcel Energy, Inc., requested relief from, and proposed alternatives to, certain inservice testing {1ST) requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) for its fifth 1 0-year 1ST program interval for Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2. The program included Relief Requests RR-01, RR-03, RR-05, RR-06 and RR-07.

The NRC staff evaluation of the subject relief requests associated with the fifth 1 0-year 1ST program (from December 21, 2014, to December 20, 2024) for pumps and valves at Prairie Island Nuclear Generating Plant, Units 1 and 2, is as follows:

For Relief Requests RR-01 and RR-03, relief is authorized pursuant to 10 CFR 50.55a(f)(6)(i) for the fifth 1 0-year intervaL on the basis that compliance with the Code requirements are impracticaL For Relief Request RR-05, relief is authorized pursuant to 10 CFR 50.55a(a)(3)(i) on the basis that the proposed alternative provides an acceptable level of quality and safety, and is in compliance with the ASME OM Code requirements.

For Relief Request RR-06 and RR-07. relief is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) on the basis that the proposed alternatives provide reasonable assurance that the affected components are operationally ready, and 1s in compliance with the ASME OM Code requirements.

The staff further concludes that granting relief, as discussed above, will not endanger life or property or the common defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

If you have any questions, please contact the NRC Project Manager, Scott P. Wall at 301-415-2855 or via e-mail at Scott.Wall@nrc.gov.

Docket Nos. 50-282 and 50-306

Enclosure:

Safety Evaluation cc w/enclosure: Distribution via ListServ Sincerely, v1 L. P Ito, Chief Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR RELIEF REQUESTS RELATED TO THE FIFTH 10-YEAR INSERVICE TESTING PROGRAM INTERVAL NORTHERN STATES POWER COMPANY-MINNESOTA PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306

1.0 INTRODUCTION

By letter dated April 9, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14099A283), as supplemented by letter dated September 19, 2014 (ADAMS Accession No. ML14265A090), Northern States Power Company-Minnesota (NSPM, the licensee), doing business as Xcel Energy, Inc., requested relief from, and proposed alternatives to, certain inservice testing (1ST) requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) for its fifth 1 0-year 1ST program interval for Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (1 0 CFR) 50.55a(a)(3)(i),

the licensee requested to use the proposed alternatives in Relief Requests RR-01, RR-03, and RR-05 on the basis that the alternatives provide an acceptable level of quality and safety.

Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee requested to use the proposed alternatives in Relief Requests RR-06 and RR-07 on the basis that the alternatives provide reasonable assurance that the components are operationally ready.

2.0 REGULATORY EVALUATION

The regulations in 10 CFR 50.55a(f), "lnservice Testing Requirements," requires, in part, that 1ST of certain ASME Code Class 1, 2, and 3 components must meet the requirements of the ASME OM Code and applicable addenda, except where alternatives have been authorized or relief has been requested by the licensee and granted by the U.S. Nuclear Regulatory Commission (NRC) pursuant to paragraphs (a)(3)(i), (a)(3)(ii), or (f)(6)(i) of 10 CFR 50.55a.

The regulations in 10 CFR 50.55a(a)(3) states, in part, that alternatives to the requirements of paragraph (f) of 10 CFR 50.55a may be authorized by the NRC if the licensee demonstrates that: (i) the proposed alternative provides an acceptable level of quality and safety, or (ii)

Enclosure compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The regulations in 10 CFR 50.55a(f)(5)(iii) states, in part, that licensees may determine that conformance with certain code requirements is impractical and that the licensee shall notify the NRC and submit information in support of the determination.

The regulations in 10 CFR 50.55a(f)(6)(i) states that the NRC will evaluate determinations under paragraph (f)(5) of this section that code requirements are impractical. The NRC may grant such relief and may impose such alternative requirements as it determines is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

The PINGP fifth 10-year 1ST interval begins on December 21, 2014, and is currently scheduled to end on December 20, 2024. The fifth interval 1ST program code of record is the ASME OM Code, 2004 Edition through OMB 2006 Addenda.

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request and the NRC to grant the relief or authorize the alternatives requested by the licensee.

3.0 Technical evaluation 3.1 Relief Request RR-01 3.1.1 Code Requirements ISTB-5121, "Group A Test Procedure," (b)states, "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-5222, "Group 8 Test Procedure," (c) states, "System resistance may be varied as necessary to achieve the reference point."

ISTB-5123, "Comprehensive Test Procedure," (b) states,"For centrifugal and vertical line shaft pumps, 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-5221, "Group A Test Procedure," (b) states, "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-5223, "Comprehensive Test Procedure," (b) states, "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."

3.1.2 Specific Relief Requested The licensee requested relief from ISTB-5121, ISTB-5221, ISTB-5222, and ISTB-5223 which requires that pump testing be performed with the pump operating at a specified reference point.

Relief is requested for the following pumps:

Table 1 Pump Description Class Catego_ry_

145-121 11 Component Cooling Pump 3

A 145-122 12 Component Cooling Pump 3

A 245-121 21 Component Cooling Pump 3

A 245-122 22 Component Cooling Pump 3

A 045-091 121 Motor-Driven Cooling Water Pump 3

A 145-392 12 Diesel-Driven Cooling Water Pump 3

B 245-392 22 Diesel-Driven Cooling Water Pump 3

B 3.1.3 Licensee's Basis for Relief The Component Cooling (CC) system removes heat from the Residual Heat Removal (RHR) system by providing component cooling water to the RHR heat exchangers during RHR system operation. The CC system removes heat from the RHR, Safety Injection (SI), Containment Spray (CS) and Reactor Coolant systems (RCSs) by providing component cooling water to the system pumps during their operation. Per the Updated Safety Analysis Report (USAR) Section 1 0.4.2.2, essential cooling loads also include spent fuel pool heat exchangers and primary sample coolers.

The 121 vertical motor-driven (MD) cooling water (CL) pump serves as a diverse means of providing cooling water that is independent of the diesel-driven CL pumps. The Station Blackout I Electrical Safeguards Upgrade modification upgraded the 121 MDCL pump to safeguards status and changed the power supply to an essential safeguards diesel-backed power supply.

Each of the diesel-driven (DD) CL pumps, 12 DDCL pump and 22 DDCL pump, are capable of supplying all essential cooling water loads during an accident. Only one cooling water pump is required for the safe shut down of both units (accident in only one unit). The DDCL pumps are capable of providing a safeguards water supply to the Auxiliary Feedwater pumps. Each DDCL pump is capable of supplying sufficient cooling to the Unit 1 emergency diesel generators (EDG), air compressors, CC heat exchangers, containment fan-coil units, and the auxiliary building unit coolers.

In order to perform accurate trending and data analysis, the use of an accurate reference value is important. The complexities of the flow control system used for these pumps make exact duplication of the reference points difficult.

CL and CC pumps operate during a variety of flow rates, differential pressure conditions and changing system loading conditions due to plant heat loads, thus it is not practical to duplicate the exact reference point for each pump test.

3.1.4 Licensee's Proposed Alternative The licensee proposed to use ASME OM Code Case OMN-16, Revision 1, "Use of a Pump Curve for Testing," in lieu of the ASME OM Subsection ISTB requirements. The pumps will be tested in a range of flows, and the results compared to acceptance criteria based upon a portion of the pump curve and the hydraulic acceptance criteria given in ISTB.

Plotting a pump curve for flow and differential pressure over the range of conditions expected during the systems' normal operation would allow evaluation of the pump in as-found system conditions. The proposed alternatives will adequately indicate normal pump degradation.

3.1.5. NRC Staff Evaluation of RR-01 Paragraphs ISTB-5121(b) and ISTB-5123(b) for centrifugal pumps, and paragraphs ISTB-5221 (b) and ISTB-5223(b) for vertical line shaft pumps, require that pump flow rate and differential pressure be evaluated against reference values to monitor pump condition and to allow detection of degradation. The component cooling pumps, diesel cooling water pumps and the motor-driven cooling water pump operate under a variety of flow rate and differential pressure conditions. Varying the flow rate of these pumps is impractical during normal plant operating conditions because of the potential loss of adequate flow to heat exchangers and the potential of creating plant transients. Imposing the ASME OM Code requirements on the licensee would be a burden in that interruption of cooling water flow could cause a reactor transient or a trip. The licensee has proposed to test the component cooling water pumps, diesel cooling water pumps and the motor-driven cooling water pump over a range of flows using the guidelines of ASME OM Code Case OMN-16, "Use of a Pump Curve for Testing."

The NRC staff has reviewed the Code Case OMN-16, Revision 1; however, the NRC has not approved this code case in Regulatory Guide (RG) 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code". ASME OM Code Case OMN-16 is a replacement for Code Case OMN-9. Because of a greater potential for error associated with the use of pump curves, the NRC staff approved Code Case OMN-9 with conditions for developing and implementing the pump curves. The NRC has approved Code Case OMN-9 with conditions as noted in RG 1.192, for setting reference values as required by ISTB-5121 and ISTB-5123.

Additionally Code Case OMN-16, Revision 1, from the 2006 Addenda of the ASME OM Code, has incorporated the staff's conditions imposed for the use of Code Case OMN-9, as listed in RG 1.192.

The NRC staff finds that the use of pump curves for reference values of flow rate and differential pressure is acceptable when it is impractical to establish a fixed set of reference values. Pump curves represent a set of infinite reference points of flow rate and differential pressure. The NRC staff determines that establishing a reference curve for the pump when it is known to be operating acceptably and basing the acceptance criteria on this curve are acceptable and can permit evaluation of pump condition and detection of degradation.

3.1.6 Conclusion Based on the above evaluation, the staff grants the licensee's request for relief pursuant to 10 CFR 50.55a(f)(6)(i) on the basis that compliance with the Code requirements is impractical and that the alternative provides reasonable assurance of the operational readiness of the pumps listed in Table 1. The NRC staff further concludes that granting the relief will not endanger life or property or the common defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.

The NRC staff authorizes the proposed alternative in RR-01 for the fifth 1ST interval at PINGP currently scheduled to begin on December 21, 2014, and is currently scheduled to end on December 20, 2024.

3.2 Relief Request RR-03 3.2.1 Code Requirements ISTB-3540, "Vibration", (b), states, "On vertical line shaft pumps, measurements shall be taken on the upper motor-bearing housing in three approximately orthogonal directions, one of which is axial direction."

3.2.2 Specific Relief Requested The licensee requested relief from ISTB-3540(b) for the following pumps:

Table 2 Pump Description Class Category 045-091 121 MDCL Pump 3

A 145-392 12 DDCL Pump 3

B 245-392 22 Diesel-Driven Cooling Water Pump 3

B 3.2.3 Licensee's Basis for Relief The 121 vertical MDCL pump serves as a diverse means of providing cooling water that is independent of the DDCL pumps. The Station Blackout I Electrical Safeguards Upgrade modification upgraded the 121 MDCL pump to safeguards status and changed the power supply to an essential safeguards diesel-backed power supply.

Each of the DDCL pumps, 12 DDCL pump and 22 DDCL pump, are capable of supplying all essential cooling water loads during an accident. Only one cooling water pump is required for the safe shut down of both units (accident in only one unit). The DDCL pumps are capable of providing a safeguards water supply to the Auxiliary Feedwater pumps. Each DDCL pump is capable of supplying sufficient cooling to the Unit 1 EDGs, air compressors, CC heat exchangers, containment fan-coil units, and the auxiliary building unit coolers.

ISTB-3540(b) specifies that the vibration reading locations be on the upper motor-bearing housing. Inaccessibility due to pump design precludes the taking of the required vibration measurements at certain ASME OM Code-specified locations on the subject pumps. Therefore, it is impractical to meet the ASME OM Code requirements. The pumps would have to be redesigned or replaced to accommodate compliance with the ASME OM Code.

The driver for the DDCL pumps is a diesel engine coupled to a right angle drive. The pump bearing is inaccessible for vibration measurements. The thrust from the pump and driver would be transmitted to the right angle drive, thus monitoring of vibration levels at this location will give an acceptable indication of any pump degradation.

The design of the MDCL water pump limits access to the upper thrust bearing housing to take vibration readings with a portable instrument while the pump is running. To climb to the top of the motor while it is running is a potential personnel hazard. Additionally, to remove the bearing housing cover is a potential personnel hazard while the pump is running, and thus taking direct readings is not practical. Vibration measurements taken on the pump housing in three orthogonal directions, one being in the axial direction, will give an acceptable indication of any pump degradation. The axial vibration from the upper motor thrust bearing would be transmitted to the motor housing.

3.2.4 Licensee's Proposed Alternative The licensee proposed that DDCL pump vibration measurements will be taken on the right angle drive of the pumps in three orthogonal directions, one of which is the axial direction. One additional vibration measurement will be taken on the diesel engines.

MDCL pump vibration measurements will be taken on the motor housing in three orthogonal directions, one of which is the axial direction. The axial reading will be taken on the side of the housing, midway between the upper and lower bearing.

3.2.5 NRC Staff Evaluation of RR-03 ISTB-3540(b) requires that, on vertical line shaft pumps, measurements shall be taken on the upper motor bearing housing in three approximately orthogonal directions, one of which is the axial direction. Inaccessibility due to pump design precludes the taking of required vibration measurements at the ASME OM Code-specified locations on the subject pumps listed in Table 2; therefore, it is impractical to meet the ASME OM Code requirements. The pumps would have to be redesigned or replaced to accommodate compliance with the ASME OM Code. Since the thrust from the pump and driver in the case of the DDCL pumps would be transmitted to the right angle drive, monitoring vibration levels at this location will give an acceptable indication of pump degradation and provides an acceptable level of quality and safety. The NRC staff finds that in the case of the MDCL pump, the axial vibration from the upper motor thrust bearing would be transmitted to the motor housing, and vibration measurements taken on the pump housing in three orthogonal directions, one being in the axial direction, will give an acceptable indication of pump degradation.

3.2.6 Conclusion Based on the above evaluation, the NRC staff grants the licensee's request for relief pursuant to 10 CFR 50.55a(f)(6)(i) on the basis that compliance with the Code requirements is impractical and that the alternative provides reasonable assurance of the operational readiness of the pumps listed in Table 2. The staff further concludes that granting the relief will not endanger life or property or the common defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.

The NRC staff authorizes the proposed alternative in RR-03 for the fifth 1ST interval at PINGP currently scheduled to begin on December 21, 2014, and is currently scheduled to end on December 20, 2024.

3.3 Relief Request RR-05 3.3.1 Code Requirements ISTB-3300, "Reference Values," (a), states, "Initial reference values shall be determined from the results of testing meeting the requirements of ISTB-31 00, Preservice Testing, or from the results of the first inservice test."

ISTB-3300(d), states, "Reference values shall be established at a point(s) of operation (reference point) readily duplicated during subsequent tests."

ISTB-3300(f), states, "All subsequent test results shall be compared to these initial reference values or to new reference values established in accordance with ISTB-3310, ISTB-3320, or ISTB-6200(c)."

ISTB-3540, "Vibration," (a) states, "On centrifugal pumps, except vertical line shaft pumps, measurements shall be taken in a plane approximately perpendicular to the rotating shaft in two approximately orthogonal directions on each accessible pump-bearing housing. Measurement shall also be taken in the axial direction on each accessible pump thrust bearing housing."

ISTB-5121, "Group A Test Procedure," (e), states, "All deviations from the reference values shall be compared with the ranges of Table ISTB-5121-1 and corrective action taken as specified in ISTB-6200. Vibration measurements shall be compared to both the relative and absolute criteria shown in the alert and required action ranges of Table ISTB-5121-1. For example, if vibration exceeds either 6Vr or 0.7 in./sec [inches per second](1.7 em/sec), the pump is in the required action range."

ISTB-6200, "Corrective Action," (a), "Alert Range," states, "If the measured test parameter values fall within the alert range of Table ISTB-5121-1, Table ISTB-5221-1, Table ISTB-5321-1, or Table ISTB-5321-2, as applicable, the frequency of testing specified in ISTB-3400 shall be doubled until the cause of the deviation is determined and the condition is corrected."

3.3.2 Specific Relief Requested Alternative testing was requested for the following centrifugal pumps:

Table 3 Pump Description Class Category 045-591 121 Control Room Chilled Water Pump 3

A 045-592 122 Control Room Chilled Water Pump 3

A 3.3.3 Licensee's Basis for Relief In its April 9, 2014 request, the licensee stated:

The ASME OM Code, paragraph ISTB-3540, requires that for centrifugal pumps, vibration measurements shall be taken in a plane approximately perpendicular to the rotating shaft in two approximately orthogonal directions on each accessible pump-bearing housing. Measurement shall also be taken in the axial direction on each accessible pump thrust bearing housing. These measurements are required to be compared with the ASME OM Code vibration acceptance criteria as specified in Table ISTB-5121-1 to determine if the measured values are acceptable.

Table ISTB-5121-1 states that, if during an inservice test, a vibration measurement exceeds 2.5 times the previously established reference value (Vr).

the pump is considered in the alert range. The frequency of testing is then doubled in accordance with paragraph ISTB-6200(a), until the cause of the deviation is determined and the condition is corrected and the vibration level returns to the acceptable range level. Pumps whose vibration is measured as greater than 6 times Vr are considered to be in the required action range, and must be declared inoperable until cause of the deviation has been determined and the condition is corrected. Per ISTB-3300(c) the vibration reference values shall be established only when the pump is known to be operating acceptably.

For pumps whose absolute magnitude of vibration is an order of magnitude below the absolute vibration limits in Table ISTB-5121-1, a relatively small increase in vibration magnitude may cause the pump to enter the alert or required action range. These instances may be attributed to variation in flow, instrument accuracy, or other noise sources that would not be representative of actual pump degradation. Pumps that operate in this region are typically referred to as "smooth-running." Based on a small acceptable range, a smooth running pump could be subjected to unnecessary corrective action.

Each of these pumps [listed in Table 3] has at least one Vr value that is currently less than 0.05 in./sec. In order to avoid unnecessary corrective actions, the licensee proposed a minimum value for Vr of 0.05 in./sec. This minimum value would be applied to individual pump vibration locations with reference vibration values less than or equal to 0.05 in./sec. Therefore, the smallest ASME OM Code Acceptable Range limit for any 1ST pump vibration measurement location would be no lower than 2.5 times Vr, or 0.125 in./sec. Likewise, the smallest ASME OM Code Alert Range limit for any 1ST pump vibration measurement location for which the pump would be inoperable would be no lower than 6 times Vr, or 0.300 in/sec. ASME OM Table ISTB-5121-1 specifies a vibration Acceptable Range of 0.325 to 0.7 in/sec for pumps<:: 600 rpm (revolutions per minute).

In addition to the requirements of ISTB for inservice testing, pumps in the PINGP lnservice Test Program are also included in the PINGP Predictive Maintenance (PdM) Program. The PINGP PdM Program currently employs predictive monitoring techniques and performs vibration analysis beyond the trending of overall vibration levels required by the ASME OM Code Sections ISTB-5321 (d) and ISTB-5323(d), including spectral and waveform analysis to provide early identification of equipment issues. When warranted, the PdM Program can also employ infrared thermography (including bearing temperature trending) and ultrasonic technologies to provide diverse understanding of pump degradation identified by vibration trends as deemed necessary under the NSPM Corrective Action Program (CAP). While oil sampling and analysis is also a part of the PINGP PdM, it is not applicable to the control room chilled water pumps, which have grease lubricated bearings.

If the measured parameters as noted above are outside the normal operating range or are determined by analysis to be trending toward an unacceptable degraded state, appropriate actions are taken that may include: initiation of a Condition Report (CR), increased monitoring to establish a rate of change, review of component specific information to identify the cause of the condition, and removal of the pump from service to perform maintenance. Experience gathered by the PINGP PdM Program has shown that changes in vibration levels in the range of 0.05 in/sec do not normally indicate significant degradation in pump performance.

3.3.4 Licensee's Proposed Alternative In its request, the licensee stated that, in lieu of applying the vibration acceptance criteria ranges specified in Table ISTB-5121-1, the smooth running pumps listed in Table 3 with a measured vibration reference values at or below 0.05 in/sec, will have subsequent test results for those locations compared to an Acceptable Range limit of 0.125 in/sec and an Alert Range limit of 0.300 in/sec. These proposed ranges will be applied to vibration test results during both Group A and comprehensive pump tests.

The licensee further stated that, using the provisions of this relief request as an alternative to the specific requirements of ISTB identified above, this alternative will provide adequate indication of pump performance and continue to provide an acceptable level of quality and safety without unnecessarily imposing corrective actions since changes in vibration levels in the range of 0.05 in/sec do not normally indicate significant degradation in pump performance.

The licensee concluded that, using the provisions of this relief request as an alternative to the vibration acceptance criteria ranges specified in Table ISTB-5121-1 provides an acceptable level of quality and safety since the alternative provides reasonable assurance of pump operational readiness and the ability to detect pump degradation.

3.3.5 NRC Staff Evaluation of RR-05 The ASME OM Code requires that the vibration of all safety-related pumps be measured. For centrifugal pumps, paragraph ISTB-3540(a) notes that vibration measurements shall be taken in a plane approximately perpendicular to the rotating shaft in two approximately orthogonal directions on each accessible pump-bearing housing. Measurement shall also be taken in the axial direction on each accessible pump thrust bearing housing. These measurements are required to be compared with the ASME OM Code vibration acceptance criteria as specified in Table ISTB-5121-1 to determine if the measured values are acceptable.

Table ISTB-5121-1 shows that, if during an inservice test, a vibration measurement on a centrifugal pump exceeds 2.5 times the reference value (Vr), previously established as required by ISTB-3300, the pump is considered to be in the alert range. The frequency of testing is then doubled in accordance with ISTB-6200 until the cause of the deviation is determined, the condition is corrected, and the vibration level returns below the alert range. Pumps, whose vibration is measured at greater than 6 times Vr, are considered to be in the required action range and must be declared inoperable until the cause of the deviation has been determined and the condition is corrected. Per ISTB-3300, the vibration reference values shall be established only when the pump is known to be operating acceptably.

The NRC staff has previously authorized a minimum vibration level of 0.05 in/sec for "smooth running" pumps at several nuclear plants. However, monitoring only the vibration levels of "smooth running" pumps has been shown to be insufficient for determining pump degradation.

At one particular plant, the NRC staff authorized a minimum reference value of 0.1 in/sec. A pump bearing at this plant experienced a significant degradation even though the pump vibration levels were below the minimum reference value in the approved alternative. The bearing degradation was discovered during PdM program activities.

The licensee's alternative combines a minimum vibration value of 0.05 in/sec for two chilled water "smooth running" pumps listed in Table 3 with additional monitoring of the pumps using a PdM program that includes vibration analysis beyond that required by the ASME OM Code, including bearing temperature trending, oil analysis, and thermography analysis, as applicable.

The licensee notes that if any of the measured parameters, including predictive maintenance values, are outside of the normal operating range or are determined by analysis to be trending towards an unacceptable degraded state, appropriate actions will be taken. These actions include increased monitoring to establish a rate of change, review of component specific information to identify the cause of the condition, and removal of the pump from service to perform maintenance. The proposed alternative is consistent with the objectives of the 1ST, which is to monitor degradation in safety-related components.

Based on the minimum vibration reference value of 0.05 in/sec noted in this request and the licensee's implementation of the proposed PdM program, the NRC staff finds that the alert and required action limits specified in the request for the pumps listed in Table 3 sufficiently address previously undetected pump problems and provide an adequate indication of pump performance. The licensee's PdM program is designed to detect problems involving unacceptable mechanical conditions in advance of either of the chilled water pumps reaching the overall vibration alert or action limits. Therefore, the NRC staff finds that the licensee's proposed alternative provides an acceptable level of quality and safety to the specific ASME OM Code requirements of ISTB-3300(a), ISTB-3300(d), ISTB-3300(f), ISTB-5121, and ISTB-6200.

3.3.6 Conclusion Based on the above evaluation, the NRC staff finds that the proposed alternative described in alternative request RR-05 provides an acceptable level of quality and safety for the pumps listed in Table 3. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(i), and is in compliance with the ASME OM Code's requirements.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.

The NRC staff authorizes the proposed alternative in RR-05 for the fifth 1ST interval at PINGP currently scheduled to begin on December 21, 2014, and is currently scheduled to end on December 20, 2024.

3.4 Relief Request RR-06 3.4.1 Code Requirements This request applies to the frequency specifications of the ASME OM Code. The frequencies for tests given in the ASME OM Code include the following but do not include a tolerance band.

ISTA-3120, "lnservice Test Interval," (a) states, "The frequency for inservice testing shall be in accordance with the requirements of Section 1ST."

ISTB-3400, "Frequency of lnservice Tests," states, "An inservice test shall be run on each pump as specified in Table ISTB-3400-1."

ISTC-3510, "Exercising Test Frequency," states, "Active Category A, Category B, and Category C check valves shall be exercised nominally every 3 months, except as provided by ISTC-3520, ISTC-3540, ISTC-3550, ISTC-3570, ISTC-5221, and ISTC-5222. Power-operated valves shall be exercise tested once per fuel cycle."

ISTC-3540, "Manual Valves," states, "Manual valves shall be full-stroke exercised at least once every 2 years, except where adverse conditions may require the valve to be tested more frequently to ensure operational readiness. Any increased testing frequency shall be specified by the Owner. The valve shall exhibit the required change of obturator position."

ISTC-3630, "Leakage Rate for Other Than Containment Isolation Valves," (a) "Frequency,"

states, "Tests shall be conducted at least once every 2 years."

ISTC-3700, "Position Verification Testing," states, in part, "Valves with remote position indicators shall be observed locally at least once every 2 years to verify that valve operation is accurately indicated."

ISTC-5221, "Valve Obturator Movement," (c)(3) states, "At least one valve from each group shall be disassembled and examined at each refueling outage; all valves in each group shall be disassembled and examined at least once every 8 years."

Appendix I, 1-1320, "Test Frequencies, Class 1 Pressure Relief Valves," (a), "5-Year Test Interval," states, in part, "Class 1 pressure relief valves shall be tested at least once every 5 years, starting with initial electric power generation."

Appendix I, 1-1330, "Test Frequency, Class 1 Nonreclosing Pressure Relief Devices," states, "Class 1 nonreclosing pressure relief devices shall be replaced every 5 years unless historical data indicates a requirement for more frequent replacement."

Appendix I, 1-1340, "Test Frequency, Class 1 Pressure Relief Valves That Are Used for Thermal Relief Application," states, "Tests shall be performed in accordance with 1-1320, Test Frequencies, Class 1 Pressure Relief Valves."

Appendix I, 1-1350, "Test Frequency, Classes 2 and 3 Pressure Relief Valves," (a), "10-Year Test Interval," states, in part, "Classes 2 and 3 pressure relief valves, with the exception of PWR main steam safety valves, shall be tested every ten years, starting with initial power generation."

Appendix I, 1-1360, "Test Frequency, Classes 2 and 3 Nonreclosing Pressure Relief Devices,"

states, "Classes 2 and 3 nonreclosing pressure relief devices shall be replaced every 5 years, unless historical data indicates a requirement for more frequent replacement."

Appendix I, 1-1370, "Test Frequency, Classes 2 and 3 Primary Containment Vacuum Relief Valves," states, "(a) Tests shall be performed on all Classes 2 and 3 containment vacuum relief valves at each refueling outage or every 2 years, whichever is sooner, unless historical data requires more frequent testing. (b) Leak tests shall be performed on all Classes 2 and 3 containment vacuum relief valves at a frequency designated by the Owner in accordance with Table ISTC-3500-1."

Appendix I, 1-1380, "Test Frequency, Classes 2 and 3 Vacuum Relief Valves, Except for Primary Containment Vacuum Relief Valves," states, "All Classes 2 and 3 vacuum relief valves shall be tested every 2 years, unless performance data suggest the need for a more appropriate test interval."

Appendix I, 1-1390, "Test Frequency, Classes 2 and 3 Pressure Relief Devices That Are Used for Thermal Relief Application," states, "Tests shall be performed on all Classes 2 and 3 relief devices used in thermal relief application every 10 years, unless performance data indicate more frequent testing is necessary. In lieu of tests the Owner may replace the relief devices at a frequency of every 10 years, unless performance data indicate more frequent replacements are necessary."

Appendix II, 11-4000, "Condition-Monitoring Activities," (a), "Performance Improvement Activities," (1 ), states, in part, "If sufficient information is not currently available to complete the analysis required in 11-3000, or if this analysis is inconclusive, then the following activities shall be performed at sufficient intervals over an interim period of the next 5 years or two refueling outages, whichever is less, to determine the cause of failure or the maintenance patterns."

Appendix II, 11-4000, "Condition-Monitoring Activities," (b), "Optimization of Condition-Monitoring Activities," (1)(e), states, "Identify the interval of each activity. Interval extensions shall be limited to one fuel cycle per extension. Intervals shall not exceed the maximum intervals shown in Table 11-4000-1. All valves in a group sampling plan must be tested or examined again, before the interval can be extended again, or until the maximum interval would be exceeded.

The requirements of ISTA-3120, lnservice Test Interval, do not apply."

3.4.2 Specific Relief Requested Relief is requested for all pumps and valves contained within the 1ST Program scope.

3.4.3 Licensee's Basis for Relief Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee requested the relief from the frequency specifications of the ASME OM Code. The basis of the relief request is that the ASME OM Code requirement presents an undue hardship without a compensating increase in the level of quality or safety.

ASME OM Code Section 1ST establishes the inservice test frequency for all components within the scope of the Code. The frequencies (e.g., quarterly) have always been interpreted as "nominal" frequencies (generally as defined in the Table 3.2 of NUREG-1482, Revision 1) and Owners routinely applied the surveillance extension time period (i.e., grace period) contained in the plant technical specifications (TSs) surveillance requirements (SRs). The TS typically allow for a less than or equal to 25% extension of the surveillance test interval to accommodate plant conditions that may not be suitable for conducting the surveillance (SR 3.0.2). However, regulatory issues have been raised concerning the applicability of the TS "grace period" to ASME OM Code-required 1ST frequencies irrespective of allowances provided under TS Administrative Controls (i.e., PINGP TS 5.5.7, "lnservice Testing Program," invokes SR 3.0.2 for various OM Code frequencies).

The lack of a tolerance band on the ASME OM Code 1ST frequency restricts operational flexibility. There may be a conflict where a surveillance test could be required (i.e., its frequency could expire), but where it is not possible or not desired that it be performed until sometime after a plant condition or associated Limiting Condition for Operation is within its applicability.

Therefore, to avoid this conflict, the surveillance test should be performed when it can be and should be performed.

The NRC recognized this potential issue in the TS by allowing a frequency tolerance as described in TS SR 3.0.2. The lack of a similar tolerance applied to ASME OM Code testing places an unusual hardship on the plant to adequately schedule work tasks without operational flexibility.

Thus, just as with TS required surveillance testing, some tolerance is needed to allow adjusting ASME OM Code testing intervals to suit the plant conditions and other maintenance and testing activities. This assures operational flexibility when scheduling surveillance tests that minimize the conflicts between the need to complete the surveillance and plant conditions.

3.4.4 Licensee's Proposed Alternative The licensee proposed to adopt the wording of ASME OM Code Case OMN-20, repeated below, for determining acceptable tolerances for pump and valve test frequencies. This code case was approved by the ASME OM Code Standards Committee in February 2012. The proposed alternative will be utilized for the entire fifth 1 0-year interval and will apply to the various frequency specifications of the ASME OM Code for all pumps and valves contained within the 1ST Program scope.

OMN-20 1ST and earlier editions and addenda of ASME OM Code specify component test frequencies based either on elapsed time periods (e.g., quarterly, 2 years, etc.) or based on the occurrence of plant conditions or events (e.g., cold shut down, refueling outage, upon detection of a sample failure, following maintenance, etc.).

a) Components whose test frequencies are based on elapsed time periods shall be tested at the frequencies specified in Section 1ST with a specified time period between tests as shown in the table below. The specified time period between tests may be reduced or extended as follows:

1. For periods specified as less than 2 years, the period may be extended by up to 25% for any given test.

2. For periods specified as greater than or equal to 2 years, the period may be extended by up to 6 months for any given test.

3. All periods specified may be reduced at the discretion of the Owner (i.e., there is no minimum period requirement).

Period extension is to facilitate test scheduling and considers plant operating conditions that may not be suitable for performance of the required testing (e.g., performance of the test would cause an unacceptable increase in the plant risk profile due to transient conditions or other ongoing surveillance, test or maintenance activities). Period extensions are not intended to be used repeatedly merely as an operational convenience to extend test intervals beyond those specified.

Period extensions may also be applied to accelerated test frequencies (e.g., pumps in Alert Range) and other less than two year test frequencies not specified in the table below.

Period extensions may not be applied to the test frequency requirements specified in Subsection ISTD, Preservice and lnservice Examination and Testing of Dynamic Restraints (Snubbers) in Light-water Reactor Nuclear Power Plants, as Subsection ISTD contains its own rules for period extensions.

Frequency Specified Time Period Between Tests Quarterly 92 days (or every 3 months)

Semiannually 184 days J_or every 6 months)

Annually 366 days (or every year) x Years x calendar years where 'x' is a whole number of years ~ 2 b) Components whose test frequencies are based on the occurrence of plant conditions or events may not have their period between tests extended except as allowed by ASME OM Code 2004 Edition through OMb-2006 Addenda and earlier and addenda of ASME OM Code.

3.4.5. NRC Staff Evaluation of RR-06 Historically, licensees have applied and the NRC staff has accepted the standard TS definitions for 1ST intervals (including allowable interval extensions) to ASME OM Code required testing (Reference NUREG-1482 Revision 2, Section 3.1.3). Recently, the NRC staff reconsidered the allowance of the TS testing intervals and interval extensions, for 1ST not associated with TS SRs. As noted in Regulatory Issue Summary (RIS) 2012-10, "NRC Staff Position on Applying Surveillance Requirements 3.0.2 and 3.0.3 to Administrative Controls Program Tests," the NRC determined that programmatic test frequencies cannot be extended in accordance with the TS SR 3.0.2. This includes all 1ST described in the ASME OM Code not specifically required by the TS SRs.

Following this development, the NRC staff sponsored and co-authored an ASME OM Code inquiry and Code Case to modify the ASME OM Code to include TS-Iike test interval definitions and interval extension criteria. The resultant ASME OM Code Case OMN-20, as shown above, was approved by the ASME Operation and Maintenance Standards Committee and published in the 2012 Edition of the ASME OM Code. The licensee proposes to use the ASME OM Code Case OMN-20 entirely from the 2012 Edition of the ASME OM Code for grace period associated with 1ST requirements. The NRC staff notes that currently it has not approved Code Case OMN-20 in Regulatory Guide 1.192.

Implementation of ASME OM Code Case OMN-20 requires implementation of this code case in its entirety, including the above stated restrictions/limitations, without exceptions. Requiring the licensee to meet the ASME OM Code requirements, without an allowance for defined frequency and frequency extensions for 1ST of pumps and valves, results in a hardship without a compensating increase in the level of quality and safety. Based on the prior acceptance by the NRC staff of the similar TS test interval definitions and interval extension criteria, the staff finds that implementation of the test interval definitions and interval extension criteria contained in ASME OM Code Case OMN-20 is acceptable. Allowing usage of ASME Code Case OMN-20 provides reasonable assurance of operational readiness of pumps and valves subject to the ASME OM Code 1ST.

3.4.6 Conclusion As set forth above, the NRC staff determined that usage of ASME Code Case OMN-20, described in alternative request RR-06, provides reasonable assurance of operational readiness of pumps and valves subject to the ASME OM Code I ST. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii) and is in compliance with the ASME OM Code requirements.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.

The NRC staff authorizes the proposed alternative in RR-06 for the fifth 1ST interval at PINGP currently scheduled to begin on December 21, 2014, and is currently scheduled to end on December 20, 2024.

3.5 Relief Request RR-07 3.5.1 Code Requirements Appendix I, 1-1320, "Test Frequencies, Class 1 Pressure Relief Valves, (a), "5-Year Test Interval," states "Class 1 pressure relief valves shall be tested at least once every 5 years, starting with initial electric power generation. No maximum limit is specified for the number of valves to be tested within each interval; however, a minimum of 20% of the valves from each valve group shall be tested within any 24-month interval. This 20% shall consist of valves that have not been tested during the current 5-year interval, if they exist. The test interval for any individual valve shall not exceed 5 years."

Appendix I, Section 1-1350, "Test Frequency, Classes 2 and 3 Pressure Relief Valves," (a),

"1 0-year Test Interval,' states, in part, "PWR [pressurized water reactor] main steam safety valves shall be tested in accordance with 1-1320."

NSPM requests that the test interval for the valves listed in Table 4 be increased from 5 years to 72 months in accordance with ASME OM Code Case, OMN-17, "Alternative Rules for Testing ASME Class 1 Pressure Relief/Safety Valves," while still maintaining the required 24-month/20 percent sampling requirement so that the test interval for any individual valve that is in service shall not exceed 72 months except that a 6-month grace period is allowed to coincide with refueling outages to accommodate extended shut down periods.

3.5.2 Specific Relief Requested Alternative testing was requested for the following Safety Relief Valves:

Table 4 Relief Description Class Category Valves RS-21-1 11 Steam Relief Header 2

c RS-21-2 11 Steam Relief Header 2

c RS-21-3 11 Steam Relief Header 2

c RS-21-4 11 Steam Relief Header 2

c RS-21-5 11 Steam Relief Header 2

c RS-21-6 12 Steam Relief Header 2

c RS-21-7 12 Steam Relief Header 2

c RS-21-8 12 Steam Relief Header 2

c RS-21-9 12 Steam Relief Header 2

c RS-21-10 12 Steam Relief Header 2

c RS-21-11 21 Steam Relief Header 2

c RS-21-12 21 Steam Relief Header 2

c RS-21-13 21 Steam Relief Header 2

c RS-21-14 21 Steam Relief Header 2

c RS-21-15 21 Steam Relief Header 2

c RS-21-16 22 Steam Relief Header 2

c RS-21-17 22 Steam Relief Header 2

c RS-21-18 22 Steam Relief Header 2

c RS-21-19 22 Steam Relief Header 2

c RS-21-20 22 Steam Relief Header 2

c 3.5.3 Licensee's Basis for Relief The primary purpose of the main steam safety valves (MSSVs) listed in Table 4 is to provide overpressure protection for the steam generators. The MSSVs also provide protection against over pressurizing the reactor coolant pressure boundary (RCPB) by providing a heat sink for the removal of energy from the RCS if the preferred heat sink, provided by the condenser and circulating water system, is not available.

Current fuel cycle lengths are at an approximate 20 month frequency; however NSPM is considering extending the cycle length to 24 months during the fifth 1 0-year interval. In doing so, this will create a hardship for testing the valves as the number of available refueling outages to complete testing will decrease, and result in testing half of the MSSV each outage thereafter (5 of 10 valves). In lieu of this, additional flexibility is required in order to allot for periodic testing of the valves and to allow for disassembly, inspection, and testing of a number of valves to which PINGP has three maintained spare valves. This is consistent with past practices prior to instituting the "in situ-testing" practices of disassembly and refurbishment of the valves.

3.5.4 Licensee's Proposed Alternative NSPM proposes that the MSSVs for PINGP Units 1 and 2 listed in Table 4 be tested in accordance with the provisions of OMN-17, "Alternative Rules for Testing ASME Class 1 Pressure Relief/Safety Valves." A minimum of 20 percent of the pressure relief valves will be tested within any 24-month interval and this 20 percent will consist of valves that have not been tested during the current 72 month interval, if they exist. The test interval for any individual valve that is in service shall not exceed 72 months except that a 6-month grace period is allowed to coincide with refueling outages to accommodate extended shut down periods. This alternative test frequency is consistent with the alternative test frequency provided in ASME Code Case OMN-17.

The relief valve testing at PINGP will consist of removal of the MSSV component requiring testing and transport to an off-site facility for testing. Upon receipt at the offsite facility the valves are subject to an as-found inspection and set pressure testing. Prior to the return of the complement of MSSVs for installation in the plant, the valves are disassembled and inspected to verify that internal surfaces and parts are free from defects or service induced wear prior to the start of the next test interval. During this process, anomalies or damage are identified and dispositioned for resolution. Damaged or worn parts, springs, gaskets, and seats are replaced as necessary. The valve seats are relapped as needed. Following reassembly, the valve's set pressure is recertified. This process is in accordance with ASME OM Code Case OMN-17 paragraphs (d) and (e).

NSPM also proposes to comply with all other OMN-17 requirements for the MSSVs including requirements for replacement with pretested valves, requirements for testing additional valves, maintenance requirements, and requirements for disassembly and inspection.

This proposed alternative will provide for disassembly and inspection of the MSSVs to verify parts are free from defects resulting from time-related degradation or maintenance induced.

This maintenance will also help to reduce the potential for setpoint drift, and increase the reliability of these safety relief valves to perform their design requirement functions. Consistent with the special maintenance requirement in Code Case OMN-17, critical components will be inspected for wear and defects, and the critical dimensions will be measured during the inspection.

Table 1, "MSSV Testing History", included in the NSPM submittal dated April9, 2014, provides the testing history for the fourth 1 0-year 1ST interval for the MSSVs being discussed.

3.5.5. NRC Staff Evaluation of RR-07 ASME OM Code, Mandatory Appendix I, does not require that safety relief valves (SRVs) be disassembled and inspected prior to the start of the five year test interval. The ASME developed Code Case OMN-17, which was published first time in the 2009 Edition of OM Code.

Code Case OMN-17 allows extension of the test interval for SRVs from five years to six years plus a six month grace period. The code case imposes a special maintenance requirement to disassemble and inspect each SRV to verify that parts are free from defects resulting from time-related degradation or maintenance-induced wear prior to the start of the extended test interval.

The licensee has provided test data to show that the subject valves have historically exhibited very limited susceptibility to time related degradation or set point drift. They have also committed to implement a disassembly and inspection program in conjunction with the extended test interval, as required by ASME OM Code Case OMN-17, in order to detect and control defects resulting from time-related degradation or service-induced wear going forward.

The NRC staff recognizes that although Mandatory Appendix I, Paragraph l-1320(a) of the ASME OM Code does not require that SRVs be routinely refurbished when tested on a 5-year interval, routine refurbishment provides additional assurance that set-pressure drift during subsequent operation is minimized. Consistent with the special maintenance requirement in Code Case OMN-17, the licensee stated that each currently installed MSSV was as-found tested, disassembled, inspected and repaired, followed by post maintenance recertification in accordance with the qualified procedure, prior to installation to verify that parts were free from defects resulting from time related degradation or maintenance induced wear. Therefore, the currently installed MSSVs comply with OMN-17.

The NRC staff finds that complying with Mandatory Appendix I, Paragraphs 1-1320 and 1-1350 for the MSSVs listed in Table 4 would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. The proposed use of ASME OM Code Case OMN-17 provides reasonable assurance that the MSSVs listed in Table 4 are operationally ready. Based on the historical performance of the set-point testing of PINGP Units 1 and 2 MSSVs and the licensee's commitments to disassemble and inspect the MSSVs prior to use, the NRC staff finds that implementation of the ASME OM Code Case, OMN-17, for the testing of the MSSVs listed in Table 4, in lieu of the requirements of ASME OM Code 2004 Edition through OMb-2006, Mandatory Appendix I, Paragraph 1-1320 of the OM Code, is acceptable.

3.5.6 Conclusion Based on the above evaluation, the NRC staff finds that the proposed alternative described in alternative request RR-07 provides an acceptable level of quality and safety the MSSVs listed in Table 4. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a{a)(3)(ii), and is in compliance with the ASME OM Code's requirements.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.

The NRC staff authorizes the proposed alternative in RR-06 for the fifth 1ST interval at PINGP currently scheduled to begin on December 21, 2014, and is currently scheduled to end on December 20, 2024.

Principal Contributors: Gurjendra S. Bedi, NRR/DE/EPNB Date: December 5, 2014

• ML14329A185

• SE transmitted via email dated 11/19/14 OFFICE NRR/DORULPL3-1/PM N RR/DORULPL3-1/LA NRR/DE/EPNB*

N RR/DORULPL3-1/PM NAME SWall MHenderson DAII~

DPelton DATE 12/04/2014 12/04/2014 11/19/2014 12/05/2014