PNP 2014-022, Response to Second Request for Additional Information Dated February 27, 2014 for Relief Request RR 4-18 - Proposed Alternative Use of ASME Code Case N-770-1 Baseline Examination

Response to Second Request for Additional Information Dated February 27, 2014 for Relief Request RR 4-18 - Proposed Alternative Use of ASME Code Case N-770-1 Baseline Examination

ML14063A089
Person / Time
Site:	Palisades
Issue date:	03/04/2014
From:	Vitale A Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PNP 2014-022
Download: ML14063A089 (14)

Text

Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant

.lintei 27780 Blue Star Memorial Highway Covert, Ml 49043-9530 Tel 269 764 2000 Anthony J. Vitale Site Vice President PNP 2014-022 March 04, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Response to Second Request for Additional Information dated February 27, 2014, for Relief Request Number RR 4-18 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination Palisades Nuclear Plant Docket 50-255 License No. DPR-20

References:

1. Entergy Nuclear Operations, Inc. letter PNP 201 4-015, Relief Request Number RR 4 Proposed Alternative, Use ofAlternate ASME Code Case N-770- 1 Baseline Examination, dated February 25, 2014 2.

NRC Electronic Mail, Request for Additional Information

- Palisades

- RR 4 Proposed Alternative, Use ofAlternate ASME Code Case N-770-1 Baseline Examination

- MF3508, dated February 26, 2014

3. Entergy Nuclear Operations, Inc. letter PNP 2014-021, Response to Request for Additional Information dated Februa,y 26, 2014, for Relief Request Number RR 4-18 Proposed Alternative, Use of Alternate ASME Code Case N-770- 1 Baseline Examination, dated March 01, 2014 4.

NRC Electronic Mail, Palisades

- AR 4 2nd Set of RAIs TAC No. MF3508, dated February 27, 2014 Sir or Madam:

In Reference 1, Entergy Nuclear Operations, Inc. (ENO) requested Nuclear Regulatory Commission (NRC) approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). NRC approval was requested by March 8, 2014.

PNP 2014-022 March 04, 2014 Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530 Tel 269 764 2000 Anthony J. Vitale Site Vice President U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Response to Second Request for Additional Information dated February 27,2014, for Relief Request Number RR 4 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination Palisades Nuclear Plant Docket 50-255 License No. DPR-20

References:

1. Entergy Nuclear Operations, Inc. letter PNP 2014-015, Relief Request Number RR 4 Proposed Alternative, Use of Altemate ASME Code Case N-770-1 Baseline Examination, dated Sir or Madam:

February 25, 2014

2. NRC Electronic Mail, Request for Additional Information - Palisades

- RR 4 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination - MF3508, dated February 26, 2014

3. Entergy Nuclear Operations, Inc. letter PNP 2014-021, Response to Request for Additional Information dated February 26,2014, for Relief Request Number RR 4 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination, dated March 01,2014

4. NRC Electronic Mail, Palisades - RR 4 2nd Set of RAJ's TAC No. MF3508, dated February 27,2014 In Reference 1, Entergy Nuclear Operations, Inc. (ENO) requested Nuclear Regulatory Commission (NRC) approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). NRC approval was requested by March 8, 2014.

PNP 2014-022 Page 2 Reference 1 is associated with the use of an alternative to the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Code Case N-770-1, as conditioned by 10 CFR 50.55a(g)(6)(ii)(F)(1) and 10 CFR 50.55a(g)(6)(ii)(F)(3), dated June 21, 2011.

In Reference 2, the NRC issued a request for additional information (RAI). ENO responded to the RAI in Reference 3.

In Reference 4, the NRC issued a second RAI. The response to the second RAI is provided in Attachment 1.

This submittal contains no proprietary information.

Summary of Commitments This letter contains no new commitments and one revision to an existing commitment.

Commitment made by letter of February 25, 2014 (Reference 1):

ENO will perform appropriate actions to meet ASME Section Xl Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in, Enclosure Table 1, of this request during the first refueling outage after a viable technology is developed to perform these examinations.

Revised commitment:

ENO will comply with 10 CFR 50.55a(g)(6)(ii)(F) for the welds identified in, Enclosure Table 1, of Relief Request Number RR 4-18 by the end of the next scheduled refueling outage (1 R24).

Sincerely, ajv/jse

(

Attachment:

1. Response to Second Request for Additional Information dated February 27, 2014, for Relief Request Number RR 4-18

Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination

2. Radiological Dose Estimates PNP 2014-022 Page 2 Reference 1 is associated with the use of an alternative to the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Code Case N-770-1, as conditioned by 10 CFR 50.55a(g)(6)(ii)(F)(1) and 10 CFR 50.55a(g)(6)(ii)(F)(3), dated June 21,2011.

In Reference 2, the NRC issued a request for additional information (RAI). END responded to the RAI in Reference 3.

In Reference 4, the NRC issued a second RAI. The response to the second RAI is provided in Attachment 1.

This submittal contains no proprietary information.

Summary of Commitments This letter contains no new commitments and one revision to an existing commitment.

Commitment made by letter of February 25, 2014 (Reference 1):

END will perform appropriate actions to meet ASME Section XI Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in, Enclosure Table 1, of this request during the first refueling outage after a viable technology is developed to perform these examinations.

Revised commitment:

END will comply with 10 CFR 50.55a(g)(6)(ii)(F) for the welds identified in, Enclosure Table 1, of Relief Request Number RR 4-18 by the end of the next scheduled refueling outage (1 R24).

Sincerely, ajv/jse

Attachment:

1. Response to Second Request for Additional Information dated February 27,2014, for Relief Request Number RR 4 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination

2. Radiological Dose Estimates

PNP 2014-022 Page 3 cc:

Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC PNP 2014-022 Page 3 cc:

Administrator, Region III, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC

ATTACHMENT 1 Response to Second Request for Additional Information dated February 27, 2014, for Relief Request Number RR 4-18 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination By letter dated February 25, 2014, Entergy Nuclear Operations (ENO) requested Nuclear Regulatory Commission (NRC) approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). By electronic mail, dated February 27, 2014, the Nuclear Regulatory Commission (NRC) submitted a second request for additional information. The requested information is provided below.

NRC Information Request Response to Question RAI-2.1 As part of the hardship associated with performing volumetric inspections this outage, a radiological total dose estimate of 37 REM was provided. However, as volumetric examinations would have been required this outage, the staff requests what portion of that dose is above the exposure to perform the examination, as required by 10 CFR 50.55(a) with appropriate planning and foresight. Please provide the basis for the dose estimates, e.g. a breakdown of doses for each weld for erecting scaffolding, conducting surveys, removing insulation, conductmg examinations, re-installing insulation, removing scaffolding, etc. Include the times required for each activity along with the estimates for general area dose rates and dose rates at 12 inches from the nozzles.

ENO Response, Radiological Dose Estimates, provides detailed radiological dose estimates for performing unplanned volumetric inspections this outage (Table 1) and dose estimates for performing the volumetric inspections with appropriate planning and foresight (Table 2). The total dose for performing unplanned volumetric inspections this outage is estimated to be approximately 37 Rem. The total dose with appropriate planning and foresight is estimated to be 14.5 Rem. provides a breakdown of dose for each weld, which includes erecting and removing scaffolding, conducting surveys, removing insulation, etc. The duration for each activity along with the general area dose rates and dose rates at 12 inches from the welds are also provided.

2.

NRC Information Request Response to Question RAI-2.2 10 CFR 50.55a(g)(6)(ii)(F) requires a volumetric inspection be performed this outage of the subject butt welds that meets the requirements of Appendix VIII of ASME Code. The proposed alternative would manage the potential for PWSCC cracking by monitoring for reactor coolant pressure boundary un/so/able though 1 of 7 ATTACHMENT 1 Response to Second Request for Additional Information dated February 27,2014, for Relief Request Number RR 4 Proposed Alternative, Use of Alternate ASME Code Case N-770-1 Baseline Examination By letter dated February 25, 2014, Entergy Nuclear Operations (END) requested Nuclear Regulatory Commission (NRC) approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). By electronic mail, dated February 27, 2014, the Nuclear Regulatory Commission (NRC) submitted a second request for additional information. The requested information is provided below.

1.

NRC Information Request - Response to Question RAI-2.1 As part of the hardship associated with performing volumetric inspections this outage, a radiological total dose estimate of 37 REM was provided. However, as volumetric examinations would have been required this outage, the staff requests what portion of that dose is above the exposure to perform the examination, as required by 10 CFR 50.55(a) with appropriate planning and foresight. Please provide the basis for the dose estimates, e.g. a breakdown of doses for each weld for erecting scaffolding, conducting surveys, removing insulation, conducting examinations, re-installing insulation, removing scaffolding, etc. Include the times required for each activity along with the estimates for general area dose rates and dose rates at 12 inches from the nozzles.

ENO Response, "Radiological Dose Estimates," provides detailed radiological dose estimates for performing unplanned volumetric inspections this outage (Table 1) and dose estimates for performing the volumetric inspections with appropriate planning and foresight (Table 2). The total dose for performing unplanned volumetric inspections this outage is estimated to be approximately 37 Rem. The total dose with appropriate planning and foresight is estimated to be 14.5 Rem. provides a breakdown of dose for each weld, which includes erecting and removing scaffolding, conducting surveys, removing insulation, etc. The duration for each activity along with the general area dose rates and dose rates at 12 inches from the welds are also provided.

2.

NRC Information Request - Response to Question RAI-2.2 10 CFR 50.55a(g)(6)(ii)(F) requires a volumetric inspection be performed this outage of the subject butt welds that meets the requirements of Appendix VIII of ASME Code. The proposed alternative would manage the potential for PWSCC cracking by monitoring for reactor coolant pressure boundary unisolable though 1 of 7

wall leakage. This is unacceptable without significant hardship or compensating basis for ensuring leaktightness. Provide the basis for why the following nondestructive examinations could not be performed in this outage for each weld:

A. The use of an ASME Code Section Xl Appendix VIII Supplement 10 qualified procedure using a manual phased array ultrasonic search unit with a large number of angles to examine the welds. The use of many angles could overcome the difficulties posed by the geometry of the weld. Additionally, if the manual phased array inspection procedure is validated by a later site-specific mockup demonstration, the inspection could be counted as a fully-qualified inspection.

B. Perform an eddy current or ultrasonic inspection from the inner diameter of the component to search for surface-breaking cracks.

C. Use a high-angle ultrasonic inspection method (e.g. a 70 degree refracted longitudinal search unit) to determine if any crack tips are in the outer 25% of the weld metal.

For A through C above, identify the estimated dose to complete the examination at each of the affected welds.

ENO Response A. To ensure reliable results of a manual phased array ultrasonic search unit with a large number of angles for examination of the subject welds, a Performance Demonstration Initiative (PDI) examination qualified to ASME Code,Section XI, Appendix VIII, Supplement 10 would be required. The complex geometry of the PNP subject welds will require mock-ups to be built in accordance with the industry standard Performance Demonstration Initiative (PDI), Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds. The use of an existing ASME Code, Section Xl, Appendix VIII, Supplement 10 qualified examination that is not PDI-qualified for the PNP weld complex geometry is not in accordance with industry guidance (i.e., NDE Implementation Focus Group) and would most likely result in the identification of indications that could not be evaluated, resulting in unnecessary repairs. Further, attempting to examine first, and then qualify the procedure later, would most likely result in the use of a technique that could not be qualified, in addition to the identification of indications that could not be evaluated and require potentially unnecessary repairs. The hardships associated with the above options are discussed below:

Use Currently Qualified Manual Phased Array Examination Performing an inspection using a PDI-qualified manual ultrasonic phased array search unit with many angles, that is not qualified to the PNP weld geometry, would be a best effort informational exam producing inspection results that 2 of 7 wall leakage. This is unacceptable without significant hardship or compensating basis for ensuring leaktightness. Provide the basis for why the following nondestructive examinations could not be performed in this outage for each weld:

A. The use of an ASME Code Section XI Appendix VIII Supplement 10 qualified procedure using a manual phased array ultrasonic search unit with a large number of angles to examine the welds. The use of many angles could overcome the difficulties posed by the geometry of the weld. Additionally, if the manual phased array inspection procedure is validated by a later site-specific mockup demonstration, the inspection could be counted as a fully-qualified inspection.

B. Perform an eddy current or ultrasonic inspection from the inner diameter of the component to search for surface-breaking cracks.

C. Use a high-angle ultrasonic inspection method (e.g. a 70 degree refracted longitudinal search unit) to determine if any crack tips are in the outer 25% of the weld metal.

For A through C above, identify the estimated dose to complete the examination at each of the affected welds.

ENO Response A. To ensure reliable results of a manual phased array ultrasonic search unit with a large number of angles for examination of the subject welds, a Performance Demonstration Initiative (PDI) examination qualified to ASME Code,Section XI, Appendix VIII, Supplement 10 would be required. The complex geometry of the PNP subject welds will require mock-ups to be built in accordance with the industry standard Performance Demonstration Initiative (PDI), "Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds." The use of an existing ASME Code,Section XI, Appendix VIII, Supplement 10 qualified examination that is not PDI-qualified for the PNP weld complex geometry is not in accordance with industry guidance (Le., NDE Implementation Focus Group) and would most likely result in the identification of indications that could not be evaluated, resulting in unnecessary repairs. Further, attempting to examine first, and then qualify the procedure later, would most likely result in the use of a technique that could not be qualified, in addition to the identification of indications that could not be evaluated and require potentially unnecessary repairs. The hardships associated with the above options are discussed below:

Use Currently Qualified Manual Phased Array Examination Performing an inspection using a PDI-qualified manual ultrasonic phased array search unit with many angles, that is not qualified to the PNP weld geometry, would be a "best effort" informational exam producing inspection results that 2 of 7

could not be further characterized. ENOs current mock-up for the subject weld locations was designed before ASME Section Xl, Appendix VIII requirements were established. That is, this mock-up does not meet the Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds, Revision C, that was developed by the PDI. Still, the mockup was used in conjunction with a current PDI-qualified manual phased array procedure, equipment, and personnel to determine if a qualified examination on this complex configuration could be produced. During the testing, known flaws within the mockup specimen could not be reliably detected. After the testing, it was determined, with EPRI, that in order to produce reliable results, the NDE Implementation Focus Group (NIFG) recommendations would have to be followed, which includes building samples and procedures that meet the approved PDI site specific configuration mockup requirements, and meet the current ASME Section Xl, Appendix VIII, Code and Code Case N-770-1 requirements.

The hardship associated with creation of a qualified examination for using manual phased array with a large number of angles is that industry precedence for the PNP weld geometry has not been demonstrated to date. As such, conceptual designs would require industry vetting prior to fabricating mock-ups and procedures. Significant input from the industry, including the NIFG, is required because current ASME codes do not adequately address the complex geometry of the subject welds. The addition of more angles adds to the complexity of an already complex exam, without an equivalent increase in exam fidelity because each search unit will require that its focus be maintained, proper inside diameter (ID) impingement angles be maintained over the entire scan, mis-orientation of angles be minimized, required examination coverage be obtained, and a sufficient sound path for calibration be available. Procedure instructions to evaluate examination results require development, such as detailed profile and plotting instructions, and flaw placement and length / depth sizing. Further, NIFG recommendations would need to be incorporated, such as the performance of in-field walkdowns, evaluation of the applicability of encoded and non-encoded techniques, and performance of computer modeling to ensure an effective probe selection and scan plan.

In addition, EPRI review of the proposed technique, fabrication of mock-ups, purchase of ultrasonic testing probes, and delivery device (scanner) design and fabrication would also be required.

Examine Welds Now and Qualify Later Examining the subject welds in the current PNP refueling outage (1 R23), with an unqualified procedure and then attempting to qualify the procedure after the refueling outage, has a low probability of success. The low probability of success is based on the fact that an ASME, Section Xl, Appendix VIII weld configuration for this complex geometry does not exist and, as such, PDI demonstrating these configurations using the current PDI-qualified method is highly unlikely. ENO has explored the use of a currently qualified procedure by 3 of 7 could not be further characterized. ENO's current mock-up for the subject weld locations was designed before ASME Section XI, Appendix VIII requirements were established. That is, this mock-up does not meet the "Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds," Revision C, that was developed by the PDI. Still, the mockup was used in conjunction with a current PDI-qualified manual phased array procedure, equipment, and personnel to determine if a qualified examination on this complex configuration could be produced. During the testing, known flaws within the mockup specimen could not be reliably detected. After the testing, it was determined, with EPRI, that in order to produce reliable results, the NDE Implementation Focus Group (NIFG) recommendations would have to be followed, which includes building samples and procedures that meet the approved PDI site specific configuration mockup requirements, and meet the current ASME Section XI, Appendix VIII, Code and Code Case N-770-1 requirements.

The hardship associated with creation of a qualified examination for using manual phased array with a large number of angles is that industry precedence for the PNP weld geometry has not been demonstrated to date. As such, conceptual designs would require industry vetting prior to fabricating mock-ups and procedures. Significant input from the industry, including the NIFG, is required because current ASME codes do not adequately address the complex geometry of the subject welds. The addition of more angles adds to the complexity of an already complex exam, without an equivalent increase in exam fidelity because each search unit will require that its focus be maintained, proper inside diameter (ID) impingement angles be maintained over the entire scan, mis-orientation of angles be minimized, required examination coverage be obtained, and a sufficient sound path for calibration be available. Procedure instructions to evaluate examination results require development, such as detailed profile and plotting instructions, and flaw placement and length / depth sizing. Further, NIFG recommendations would need to be incorporated, such as the performance of in-field walkdowns, evaluation of the applicability of encoded and non-encoded techniques, and performance of computer modeling to ensure an effective probe selection and scan plan. In addition, EPRI review of the proposed technique, fabrication of mock-ups, purchase of ultrasonic testing probes, and delivery device (scanner) design and fabrication would also be required.

Examine Welds Now and Qualify Later Examining the subject welds in the current PNP refueling outage (1 R23), with an unqualified procedure and then attempting to qualify the procedure after the refueling outage, has a low probability of success. The low probability of success is based on the fact that an ASME,Section XI, Appendix VIII weld configuration for this complex geometry does not exist and, as such, PDI demonstrating these configurations using the current PDI-qualified method is highly unlikely. ENO has explored the use of a currently qualified procedure by 3 of 7

using an existing mock-up. The mock-up contained known flaws that could not consistently be identified using currently available manual phased array techniques, and the addition of angles would not change this result. Performing such an examination prior to qualification would result in a best effort informational exam which would most likely result in additional hardships associated with evaluation and disposition of results. Performance of a best effort NDE exam, without a PDI-qualified examination demonstrated to be effective for the applicable complex weld geometry, has a high probability of producing erroneous results, such as detecting indications that cannot be further interrogated to determine validity or size. Adding to the already high probability of erroneous results is the fact that the post-fabrication radiographs of the subject welds include acceptable indications that would be detected by a manual phased array examination without a process to further characterize and evaluate them. Since the indications could not be accurately characterized and evaluated, mitigation actions could likely be required.

Mitigation actions include development of a repair design(s) which has not been approved for these weld configurations.

In order to support implementation, tooling fabrication, mock-up testing, and qualification of procedures and personnel would have to be completed. For example, the hot leg drain line design includes removal of the line and installation of a weld overlay, which, based on weld geometry, would be a pad welded over the outside diameter of the pipe. Installation of such a pad would require an NRC-approved relief request. Depending on the design of the overlay, ultrasonic test procedures, personnel, and equipment may need to be qualified for the design. Finally, in order to implement this design, the reactor would have to be defueled, the hot leg would have to be drained, and hot leg plugs would have to be designed and installed. Implementation of this emergent weld overlay would have an outage schedule impact of greater than 30 days duration given the current configuration of PNP.

Dose Estimate The estimated dose to plant personnel to complete these examinations is 37 Rem. For mitigation, a dose of at least 27 Rem would be incurred for repair work plus another 68 Rem to remove and reinstall the reactor head, defuel and refuel the reactor, and remove and the reinstall the core support barrel. The examination dose is essentially the same dose as that incurred for the unplanned volumetric exam in the RAI-2.1 response. The repair dose is based on dose measured during the mitigation of Alloy 600 branch connection welds during the current refueling outage. The reactor disassembly and reassembly is based on dose measured during the current outage.

B. A PDI-qualified ultrasonic examination technique on this complex dissimilar metal weld configuration from the ID is not available. The tooling to perform an eddy current or ultrasonic inspection from the inner diameter of the components 4 of 7 using an existing mock-up. The mock-up contained known flaws that could not consistently be identified using currently available manual phased array techniques, and the addition of angles would not change this result. Performing such an examination prior to qualification would result in a "best effort" informational exam which would most likely result in additional hardships associated with evaluation and disposition of results. Performance of a "best effort" NDE exam, without a PDI-qualified examination demonstrated to be effective for the applicable complex weld geometry, has a high probability of producing erroneous results, such as detecting indications that cannot be further interrogated to determine validity or size. Adding to the already high probability of erroneous results is the fact that the post-fabrication radiographs of the subject welds include acceptable indications that would be detected by a manual phased array examination without a process to further characterize and evaluate them. Since the indications could not be accurately characterized and evaluated, mitigation actions could likely be required.

Mitigation actions include development of a repair design(s) which has not been approved for these weld configurations. In order to support implementation, tooling fabrication, mock-up testing, and qualification of procedures and personnel would have to be completed. For example, the hot leg drain line design includes removal of the line and installation of a weld overlay, which, based on weld geometry, would be a pad welded over the outside diameter of the pipe. Installation of such a pad would require an NRC-approved relief request. Depending on the design of the overlay, ultrasonic test procedures, personnel, and equipment may need to be qualified for the design. Finally, in order to implement this design, the reactor would have to be defueled, the hot leg would have to be drained, and hot leg plugs would have to be designed and installed. Implementation of this emergent weld overlay would have an outage schedule impact of greater than 30 days duration given the current configuration of PNP.

Dose Estimate The estimated dose to plant personnel to complete these examinations is 37 Rem. For mitigation, a dose of at least 27 Rem would be incurred for repair work plus another 68 Rem to remove and reinstall the reactor head, defuel and refuel the reactor, and remove and the reinstall the core support barrel. The examination dose is essentially the same dose as that incurred for the unplanned volumetric exam in the RAI-2.1 response. The repair dose is based on dose measured during the mitigation of Alloy 600 branch connection welds during the current refueling outage. The reactor disassembly and reassembly is based on dose measured during the current outage.

B. A POI-qualified ultrasonic examination technique on this complex dissimilar metal weld configuration from the 10 is not available. The tooling to perform an eddy current or ultrasonic inspection from the inner diameter of the components 4 of?

that contain the subject welds is not currently available. Access to the inner surface is limited. Creating a qualified examination and providing physical access to the inner surface of the subject welds would be a significant hardship to ENO. Further details on the hardships associate with just the hot leg drain nozzle weld follow. Similar hardships exist with the cold leg nozzle welds.

Examination Possibilities If access to the inside diameter was possible, and limited stay times could be achieved, a surface examination using either an eddy current probe or dye penetrant would be used. Currently, remote eddy current equipment for this type of examination is not readily available and would need to be developed and demonstrated. This would take several months or more to accomplish. Another option, if remote capabilities were developed, would be to perform a dye penetrant examination. Industry operating experience shows that dye penetrant testing has not provided reliable results for detecting primary water stress corrosion cracking (PWSCC) due to the tightness of the crack openings on the surface.

If indications were found, depth sizing would not be possible and external ultrasonic examination, as discussed in the response to RAI-2.2, subsection A, above, would still be required. This would most likely result in the performance of an unnecessary repair and associated hardships discussed in the RAI-2.2, subsection A, response above.

Physical Limitations Personnel access to the inside diameter of the A hot leg to perform internal examinations is extremely limited. Access would only be possible after defueling, and then inserting a line plug into the hot leg from the reactor vessel side, draining of the hot leg and then removal of the nozzle dam from the steam generator nozzle after draining. The internal piping would be a high radiation and high contamination entry for the examination personnel. PNP does not have a line plug for the 42-inch hot leg or the examination delivery system at the current time to support examinations of the inside surface of the weld.

Dose Estimate The complexity and options in performing this examination make an estimation of dose highly variable, but the dose incurred would exceed the dose (27 Rem) incurred during mitigation of Alloy 600 branch connection welds during the current refueling outage, due to limited inside surface access.

C.

The use of a high-angle ultrasonic inspection method (e.g., a 70 degree refracted longitudinal search unit) to determine whether any crack tips are in the outer 25% of the weld metal would involve the same hardships as the use of a qualified technique that is not qualified for the PNP complex weld geometry (see RAI-2.2, subsection A, response above). Similar to the RAI-2.2, subsection A, 5 of 7 that contain the subject welds is not currently available. Access to the inner surface is limited. Creating a qualified examination and providing physical access to the inner surface of the subject welds would be a significant hardship to ENO. Further details on the hardships associate with just the hot leg drain nozzle weld follow. Similar hardships exist with the cold leg nozzle welds.

Examination Possibilities If access to the inside diameter was possible, and limited stay times could be achieved, a surface examination using either an eddy current probe or dye penetrant would be used. Currently, remote eddy current equipment for this type of examination is not readily available and would need to be developed and demonstrated. This would take several months or more to accomplish. Another option, if remote capabilities were developed, would be to perform a dye penetrant examination. Industry operating experience shows that dye penetrant testing has not provided reliable results for detecting primary water stress corrosion cracking (PWSCC) due to the tightness of the crack openings on the surface. If indications were found, depth sizing would not be possible and external ultrasonic examination, as discussed in the response to RAI-2.2, subsection A, above, would still be required. This would most likely result in the performance of an unnecessary repair and associated hardships discussed in the RAI-2.2, subsection A, response above.

Physical Limitations Personnel access to the inside diameter of the "A" hot leg to perform internal examinations is extremely limited. Access would only be possible after defueling, and then inserting a line plug into the hot leg from the reactor vessel side, draining of the hot leg and then removal of the nozzle dam from the steam generator nozzle after draining. The internal piping would be a high radiation and high contamination entry for the examination personnel. PNP does not have a line plug for the 42-inch hot leg or the examination delivery system at the current time to support examinations of the inside surface of the weld.

Dose Estimate The complexity and options in performing this examination make an estimation of dose highly variable, but the dose incurred would exceed the dose (27 Rem) incurred during mitigation of Alloy 600 branch connection welds during the current refueling outage, due to limited inside surface access.

C. The use of a high-angle ultrasonic inspection method (e.g., a 70 degree refracted longitudinal search unit) to determine whether any crack tips are in the outer 25% of the weld metal would involve the same hardships as the use of a qualified technique that is not qualified for the PNP complex weld geometry (see RAI-2.2, subsection A, response above). Similar to the RAI-2.2, subsection A, 5 of 7

response, the same issues would arise when performing an examination without qualified procedure guidance, equipment and personnel. Recent industry operating experience and guidance cautions sites about performing examinations without demonstrated procedures, equipment and personnel. Use of only a high-angle 70 degree refracted longitudinal search unit would not confirm the presence or absence of a flaw, and would likely result in an unnecessary repair.

Dose Estimate The estimated dose to plant personnel to complete these examinations is 37 Rem. For mitigation, a dose of at least 27 Rem would be incurred for repair work plus another 68 Rem to remove and reinstall the reactor head, defuel and refuel the reactor, and remove and the reinstall the core support barrel. The examination dose is essentially the same dose as that incurred for the unplanned volumetric exam in the RAI-2.1 response. The repair dose is based on dose measured during the mitigation of Alloy 600 branch connection welds during the current refueling outage. The reactor disassembly and reassembly is based on dose measured during the current outage.

It should be noted that a primary basis for the proposed alternative in the relief request are the benefits of the post weld heat treatment (PWHT) that was performed during fabrication of the subject welds. Testing and extensive industry experience demonstrate that Alloy 600 weldments that have been exposed to PWHT after welding have greatly reduced susceptibility to the occurrence of PWSCC. Additionally, calculations performed show that should a flaw of engineering size, crack growth rates are acceptably low due to PWHT. Therefore, the benefits of PWHT provide reasonable assurance of structural integrity and leak tightness which supports deferral of the required volumetric examinations to the next refueling outage (1 R24).

3.

NRC Information Request Response to Question RAI-3.1 The NRC staffs understanding is that the licensees current proposed alternative is as follows;

1) Perform periodic system leakage tests in accordance with ASME Section XI Examination Category B-P. Table IWB-2500- 7 (Reference 10).

2) Perform visual and dye penetrant surface examinations of the welds in accordance with ASME requirements. During the 2012 (7R22) and 2074 (7R23) refueling outages, visual and external surface examinations of certain welds for which relief is requested identified no evidence of through-wall cracking or leakage for these components, as identified in Enclosure Table 1.

6 of 7 response, the same issues would arise when performing an examination without qualified procedure guidance, equipment and personnel. Recent industry operating experience and guidance cautions sites about performing examinations without demonstrated procedures, equipment and personnel. Use of only a high-angle 70 degree refracted longitudinal search unit would not confirm the presence or absence of a flaw, and would likely result in an unnecessary repair.

Dose Estimate The estimated dose to plant personnel to complete these examinations is 37 Rem. For mitigation, a dose of at least 27 Rem would be incurred for repair work plus another 68 Rem to remove and reinstall the reactor head, defuel and refuel the reactor, and remove and the reinstall the core support barrel. The examination dose is essentially the same dose as that incurred for the unplanned volumetric exam in the RAI-2.1 response. The repair dose is based on dose measured during the mitigation of Alloy 600 branch connection welds during the current refueling outage. The reactor disassembly and reassembly is based on dose measured during the current outage.

It should be noted that a primary basis for the proposed alternative in the relief request are the benefits of the post weld heat treatment (PWHT) that was performed during fabrication of the subject welds. Testing and extensive industry experience demonstrate that Alloy 600 weldments that have been exposed to PWHT after welding have greatly reduced susceptibility to the occurrence of PWSCC. Additionally, calculations performed show that should a flaw of engineering size, crack growth rates are acceptably low due to PWHT. Therefore, the benefits of PWHT provide reasonable assurance of structural integrity and leak tightness which supports deferral of the required volumetric examinations to the next refueling outage (1 R24).

3.

NRC Information Request - Response to Question RAI-3.1 The NRC staff's understanding is that the licensee's current proposed alternative is as follows; "1) Perform periodic system leakage tests in accordance with ASME Section XI Examination Category B-P, Table IW8-2500-1 (Reference 10).

2) Perform visual and dye penetrant surface examinations of the welds in accordance with ASME requirements. During the 2012 (1R22) and 2014 (1R23) refueling outages, visual and external surface examinations of certain welds for which relief is requested identified no evidence of through-wall cracking or leakage for these components, as identified in Enclosure Table 1.

6 of 7

Pursuant to 10 CFR 50.55a(a)(3)(ii), ENO proposes to perform appropriate actions to meet ASME Section Xl Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in Enclosure Table 1 of this request during the first refueling outage after a viable technology is developed to perform these examinations.

The NRC staff does not find the proposed alternative for future inspections by the licensee to be acceptable. At a minimum, the NRC staff would expect the licensee to clearly identify the regulatory requirements and how those regulatory requirements will be met. The NRC staff expects the licensee to comply with 10 CFR 50.55a(G)(6)(ii)(F) during the next scheduled refueling outage.

ENO Response Regulation 10 CFR 50.55a(g)(6)(ii)(F)(l) states Licensees of existing, operating pressurized water reactors as of July 21, 2011 shall implement the requirements of ASME Code Case N-770-1, subject to the conditions specified in paragraphs (g)(6)(ii)(F)(2) through (g)(6)(ii)(F)(1 0) of this section, by the first refueling outage after August 22, 2011.

Regulation 10 CFR 50.55a(g)(6)(ii)(F)(3) states that baseline examinations for welds in Code Case N-770-1, Table 1, Inspection Items A-i, A-2, and B, shall be completed by the end of the next refueling outage after January 20, 2012.

As discussed in the cover letter, ENO is revising the commitment made in Relief Request Number RR 4-18, dated February 25, 2014, as described below.

Commitment made by letter of February 25, 2014 (Reference 1):

ENO will perform appropriate actions to meet ASME Section XI Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in Attachment 1, Enclosure Table 1, of this request during the first refueling outage after a viable technology is developed to perform these examinations.

Revised commitment:

ENO will comply with 10 CFR 50.55a(g)(6)(ii)(F) for the welds identified in, Enclosure Table 1, of Relief Request Number RR 4-18, by the end of the next scheduled refueling outage (1 R24).

7 of 7 Pursuant to 10 CFR 50.55a(a)(3)(iiJ, ENO proposes to perform appropriate actions to meet ASME Section XI Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in Enclosure Table 1 of this request during the first refueling outage after a viable technology is developed to perform these examinations. 11 The NRC staff does not find the proposed alternative for future inspections by the licensee to be acceptable. At a minimum, the NRC staff would expect the licensee to clearly identify the regulatory requirements and how those regulatory requirements will be met. The NRC staff expects the licensee to comply with 10 CFR 50.55a(G)(6)(ii)(FJ during the next scheduled refueling outage.

ENO Response Regulation 10 CFR 50.55a(g)(6)(ii)(F)(1) states "Licensees of existing, operating pressurized water reactors as of July 21, 2011 shall implement the requirements of ASME Code Case N-770-1, subject to the conditions specified in paragraphs (g)(6)(ii)(F)(2) through (g)(6)(ii)(F)(10) of this section, by the first refueling outage after August 22, 2011."

Regulation 10 CFR 50.55a(g)(6)(ii)(F)(3) states that baseline examinations for welds in Code Case N-770-1, Table 1, Inspection Items A-1, A-2, and S, shall be completed by the end of the next refueling outage after January 20, 2012.

As discussed in the cover letter, END is revising the commitment made in Relief Request Number RR 4-18, dated February 25,2014, as described below.

Commitment made by letter of February 25,2014 (Reference 1):

END will perform appropriate actions to meet ASME Section XI Code Case N-770-1 examination requirements, as required, for those dissimilar metal welds identified in Attachment 1, Enclosure Table 1, of this request during the first refueling outage after a viable technology is developed to perform these examinations.

Revised commitment:

END will comply with 10 CFR 50.55a(g)(6)(ii)(F) for the welds identified in, Enclosure Table 1, of Relief Request Number RR 4-18, by the end of the next scheduled refueling outage (1 R24).

7 of 7

ATTACHMENT 2 RADIOLOGICAL DOSE ESTIMATES 3 Pages Follow ATTACHMENT 2 RADIOLOGICAL DOSE ESTIMATES 3 Pages Follow

DOSE RATES (mrem/hr)

Profile Dectection TWS Scaffold Insulation TOTAL CONTACT 12 Inch 0/A LDWA HOURS DOSE HOURS DOSE HOURS DOSE HOURS DOSE HOURS DOSE DOSE 2

Cold Leg 1

Charging Nozzle P-50A PCS-30-RCL-1A-11/2 120 70 50 14 1

184 0.75 105 1

140 11 650 6

200 1279 2 Cold Leg 2

Drain Nozzle P-50A PCS-30-RCL-1A-5/2 400 80 25 14 1

439 0.75 120 1

160 0

0 6

150 869 3 Cold Leg PZR Spray Nozzle P-50B PCS-30-RCL-1B-10/3 1800 320 150 20 1

1970 0.75 480 1

640 6

700 6

450 4240 2 Cold Leg P-SOB PCS-30-RCL-1B-5/2 700 120 60 20 1

780 0.75 180 1

240 0

0 6

250 1450 Drain Nozzle 2 Cold Leg Charging Nozzle P-SOC PCS-30-RCL-2A-11/2 120 80 25 23 1

168 0.75 120 1

160 6

420 6

150 1018 3 Cold Leg PZR 6

Spray Nozzle P-SOC PCS-30-RCL-2A-11/3 1800 330 150 23 1

1973 0.75 495 1

660 6

700 6

250 4078 2

Cold Leg Drain Nozzle P-SOC PCS-30-RCL-2A-5/2 780 130 50 23 1

853 0.75 195 1

260 0

0 6

250 1558 2 Cold Leg Drain /

8 Letdown Nozzle P-SOD PCS-30-RCL-2B-S/2 15000 300 200 35 1

15235 0.75 450 1

600 0

0 6

450 16735 2 Hot Leg Drain Nozzle AS/G PCS-42-RCL-1H-3/2 280 100 80 50 1

410 0.75 150 1

200 0

0 7

350 1110 22012 229 3060 I 2470 Profile

- 1 person at the weld, 1 person in the G/A, 1 firewatch in the LDWA Detection

- Requires 2 people at the weld or within arms length of the weld TWS

- Requires 2 people at the weld or within arms length of the weld Superviser Oversite - 1 person at all times in G/A to LDWA 2000 RP Technician (8% of prep and inspection dose) 2587 Scaffold and Insulation dose taken from work performed in 1R23 as tracked by work order Dose Rate data extracted from surveys PLP-1401-O291, PLP-1401-0459, PLP-1401-O27S, PLP-14O2-O500 and from dose reduction planning data DESCRIPTION Area 151 WELD ID Table 1 Dose Estimate for Unplanned Weld Prep and Examinations of ALLOY 600 Welds 2500 32337 Grand Total 36924 (all dose stated in mrem) 1 of 3 DESCRIPTION 1 2" Cold Leg Charging Nozzle 2 2" Cold Leg Drain Nozzle 3

3" Cold Leg PZR Spray Nozzle 4 2" Cold Leg Drain Nozzle 5

2" Cold Leg Charging Nozzle 6

3" Cold Leg PZR Spray Nozzle 7 2" Cold Leg Drain Nozzle 8

2" Cold Leg Drain /

Letdown Nozzle 9 2" Hot Leg Drain Nozzle Table 1 Dose Estimate for Unplanned Weld Prep and Examinations of ALLOY 600 Welds Area P-50A P-50A P-50B P-50B P-50C P-5OC P-50C P-50D AS/G 151 WELD ID DOSE RATES (mrem/hr)

Profile CONTACT 12 inch G/A LDWA HOURS DOSE PCS-30-RCL-lA-11/2 120 70 50 14 1

184 PCS-30-RCL -lA-5/2 400 80 25 14 1

439 PCS-30-RCL-1B-10/3 1800 320 150 20 1

1970 PCS-30-RCL-1B-5/2 700 120 60 20 1

780 PC5-30-RCL-2A-11/2 120 80 25 23 1

168 PCS-30-RCL-2A-11/3 1800 330 150 23 1

1973 PCS-30-RCL-2A-5/2 780 130 50 23 1

853 PCS-30-RCL-2B-5/2 15000 300 200 35 1

15235 PCS-42-RCL -1 H-3/2 280 100 80 50 1

410 1 22012 1 Profile - 1 person at the weld, 1 person in the G/A, 1 firewatch in the LDWA Detection - Requires 2 people at the weld or within arms length of the weld TWS - Requires 2 people at the weld or within arms length of the weld Superviser Oversite -1 person at all times in G/A to LDWA RP Technician (8% of prep and inspection dose)

Dectection HOURS DOSE 0.75 105 0.75 120 0.75 480 0.75 180 0.75 120 0.75 495 0.75 195 0.75 450 0.75 150

~

Scaffold and Insulation dose taken from work performed in 1R23 as tracked by work order TWS Scaffold Insulation TOTAL HOURS DOSE HOURS DOSE HOURS DOSE DOSE 1

140 11 650 6

200 1279 1

160 0

0 6

150 869 1

640 6

700 6

450 4240 1

240 0

0 6

250 1450,

1 160 6

420 6

150 1018 i 1

660 6

700 6

250 4078 1

260 0

0 6

250 1558 1

600 0

0 6

450 16735 1

200 0

0 7

350 1110 1 3060 J 1 2470 j l 2500 J 32337 Grand Total 36924 (all dose stated in mrem)

Dose Rate data extracted from surveys PLP-1401-0291, PLP-1401-0459, PLP-1401-0275, PLP-1402-0500 and from dose reduction planning data 1 of 3

Table 2 Dose Estimate for Weld Prep and Examinations of ALLOY 600 Welds With Additional Dose Reduction Planning Implemented DOSE RATES (mrem/hr)

Profile Detection TWS Scffold Insulation TOTAL DESCRIPTION Area SI WELD ID

CONTACT 12 inch G/A IoWA HOURS DOSE HOURS DOSE HOURS DOSE HOURS DOSE HOURS DOSE DOSE 2 Cold Leg 1

Charging Nozzle P-SOA PCS-30-RCL-1A-11/2 120 70 30 5

1 155 0.75 105 1

140 11 495 6

180 1075 2 Cold Leg P-SOA PCS-30-RCL-1A-5/2 400 50 20 S

1 425 0.75 75 1

100 0

0 6

120 720 2

Drain Nozzle 3 Cold Leg PZR Spray Nozzle P-SOB PCS-30-RCL-1B-10/3 900 150 80 20 1

1000 0.75 225 1

300 6

700 6

450 2675 2

Cold Leg Drain Nozzle P-SOB PCS-30-RCL-1B-5/2 500 60 40 20 1

560 0.75 90 1

120 0

0 6

250 1020 2

Cold Leg Charging Nozzle P-SOC PCS-30-RCL-2A-11/2 80 50 20 20 1

120 0.75 75 1

100 6

420 6

150 865 3 Cold Leg PZR 6

Spray Nozzle P-SOC PCS-30-RCL-2A-11/3 900 155 80 23 1

1003 0.75 233 1

310 6

700 6

250 2496 2 Cold Leg Drain Nozzle P-SOC PCS-30-RCL-2A-5/2 400 65 30 23 1

453 0.75 98 1

130 0

0 6

250 931 2 Cold Leg Drain /

P-50D PCS-30-RCL-2B-5/2 500 100 100 35 1

635 0.75 iSO 1

200 0

0 6

450 1435 8

Letdown Nozzle 2 Hot Leg Drain Nozzle AS/G PCS-42-RCL-1H-3/2 140 80 60 50 1

250 0.75 120 1

160 0

0 7

350 880 4601 1170 1560 2315 2450 12096 Profile

- 1 person at the weld, 1 person in the G/A, 1 firewatch in the LDWA Detection

- Requires 2 people at the weld or within arms length of the weld Grand Total 14564 TWS

- Requires 2 people at the weld or within arms length of the weld Superviser Oversite

- 1 person at all times in G/A to LDWA 1500 (all dose stated in mrem)

RP Technician (8% of prep and inspection dose) 968 Scaffold and Insulation dose taken from work performed in 1R23 as tracked by work order Dose Rate data extracted from surveys PLP-14O1-0291, PLP-1401-O459, PLP-1401-O275, PLP-14-2-0500 and from dose reduction planning data.

2 of 3 DESCRIPTION Area 1 2" Cold Leg P-50A Charging Nozzle 2 2" Cold leg P-50A Drain Nozzle 3 3" Cold leg PZR P-50B Spray Nozzle 4 2" Cold leg P-50B Drain Nozzle 5 2" Cold leg P-50C Charging Nozzle 6 3" Cold leg PZR P-50C Spray Nozzle 7 2" Cold leg P-5OC Drain Nozzle 8 2" Cold Leg Drain /

P-50D letdown Nozzle 9 2" Hot Leg AS/G Drain Nozzle Table 2 Dose Estimate for Weld Prep and Examinations of ALLOY 600 Welds With Additional Dose Reduction Planning Implemented 151 WELD 10 DOSE RATES (mrem/hr)

Profile CONTACT 12 inch G/A LDWA HOURS DOSE PCS-30-RCl-1A-11/2 120 70 30 5

1 155 PCS-30-RCl-1A-5/2 400 50 20 5

1 425 PCS-30-RCl-1B-10/3 900 150 80 20 1

1000 PCS-30-RCl-1B-5/2 500 60 40 20 1

560 PCS-30-RCl-2A-11/2 80 50 20 20 1

120 PCS-30-RCl-2A-11/3 900 155 80 23 1

1003 PCS-30-RCl-2A-5/2 400 65 30 23 1

453 PCS-30-RCl-2B-5/2 500 100 100 35 1

635 PCS-42-RCl-1H-3/2 140 80 60 50 1

250 l ~

Profile -1 person at the weld, 1 person in the G/A, 1 firewatch in the lDWA Detection - Requires 2 people at the weld or within arms length of the weld TWS - Requires 2 people at the weld or within arms length of the weld Detection TWS Scaffold HOURS DOSE HOURS DOSE HOURS DOSE 0.75 105 1

140 11 495 0.75 75 1

100 0

0 0.75 225 1

300 6

700 0.75 90 1

120 0

0 0.75 75 1

100 6

420 0.75 233 1

310 6

700 0.75 98 1

130 a

0 0.75 150 1

200 0

0 0.75 120 1

160 0

0

'- ~170 J 1560 2315 Grand Total Insulation HOURS DOSE 6

180 6

120 6

450 6

250 6

150 6

250 6

250 6

450 7

350 2450 14564 Superviser Oversite - 1 person at all times in G/A to LDWA 1 1500]

(all dose stated in mrem)

RP Technician (8% of prep and inspection dose) 968 Scaffold and Insulation dose taken from work performed in 1R23 as tracked by work order Dose Rate data extracted from surveys PLP-1401-0291, PLP-1401-0459, PLP-1401-0275, PlP-14-2'()500 and from dose reduction planning data.

2 of 3 TOTAL I DOSE 1075 720 I

2675 I

1020 865 2496 931 1435 880 12096

Acronyms and Component Identificaton Numbers PZR Pressurizer P-50A Primary Coolant Pump P-50A P-50B Primary Coolant Pump P-50B P-50C Primary Coolant Pump P-50C P-50D Primary Coolant Pump P-50D A S/G Steam Generator E-50A G/A General Area LDWA Low Dose Waiting Area Profile Examination Preparation Activities TWS Through Wall Sizing RP Radiation Protection 1 R23 Refueling Outage Number 23 3 of 3 Acronyms and Component Identification Numbers PZR - Pressurizer P-50A - Primary Coolant Pump P-50A P-50B - Primary Coolant Pump P-50B P-50C - Primary Coolant Pump P-50C P-50D - Primary Coolant Pump P-50D A S/G - Steam Generator E-50A G/A - General Area LDWA-Low Dose Waiting Area Profile - Examination Preparation Activities TWS - Through Wall Sizing RP - Radiation Protection 1 R23 - Refueling Outage Number 23 3 of 3