PNP 2014-019, Relief Request Number RR 4-19 Proposed Alternative to the Requirements of ASME Code Case N-638-4

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Relief Request Number RR 4-19 Proposed Alternative to the Requirements of ASME Code Case N-638-4
ML14057A766
Person / Time
Site: Palisades 
Issue date: 02/26/2014
From: Vitale A
Entergy Nuclear Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
PNP 2014-019
Download: ML14057A766 (9)
v • d • e


Text

Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant

27780 Blue Star Memorial Highway Covert, Ml 49043-9530 Tel 269 764 2000 Anthony J. Vitale Site Vice President PNP 2014-019 February 26, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Relief Request Number RR 4-19 Proposed Alternative to the Requirements of ASME Code Case N-638-4 Palisades Nuclear Plant Docket 50-255 License No. DPR-20

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(a)(3)(ii), Entergy Nuclear Operations, Inc. (ENO) hereby requests NRC approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). This alternative is for the current fourth 10-year ISI interval.

The request 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-638-4, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique, dated October 5, 2006.

To support the startup of PNP following the current refueling outage, ENO requests approval of this alternative by March 8, 2014.

This letter contains no new commitments and no revised commitments.

Sincerely,%,

ajv/jse AE

~ ntergy PNP 2014-019 February 26, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 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

SUBJECT:

Relief Request Number RR 4 Proposed Alternative to the Requirements of ASME Code Case N-638-4 Palisades Nuclear Plant Docket 50-255 License No. DPR-20

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(a)(3)(ii), Entergy Nuclear Operations, Inc. (ENO) hereby requests NRC approval of the Request for Relief for a Proposed Alternative for the Palisades Nuclear Plant (PNP). This alternative is for the current fourth 10-year lSI interval.

The request 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-638-4, "Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique," dated October 5,2006.

To support the startup of PNP following the current refueling outage, ENO requests approval of this alternative by March 8, 2014.

This letter contains no new commitments and no revised commitments.

Sincerely, ajv/jse

PNP 201 4-019 Page 2

Attachment:

Relief Request Number RR4-19 Proposed Alternative cc:

Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USN RC PNP 2014-019 Page 2

Attachment:

Relief Request Number RR4-19 Proposed Alternative cc:

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

ATTACHMENT ENTERGY NUCLEAR OPERATIONS, INC.

PALISADES NUCLEAR PLANT RELIEF REQUEST NUMBER RR 4-19 PROPOSED ALTERNATIVE in Accordance with 10 CFR 50.55a(a)(3)(ii)

Hardship or Unusual Difficulty Without Compensating Increase in Level of Quality and Safety 1.

ASME Code Component(s) Affected! Applicable Code Edition Components / Numbers:

Pressurizer Safety Relief Valve RV-1 041, weld number PCS-6-PRS-1 Cl-i Code of Record:

American Society of Mechanical Engineers (ASME) Section Xl, 2001 Edition through 2003 Addenda as amended by 10 CFR 50.55a ASME Code Case N-638-4, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique,Section XI, Division 1, (Reference 2)

==

Description:==

Dissimilar metal in the pressurizer safety relief valve nozzle Unit / Inspection Interval:

Palisades Nuclear Plant (PNP)/ Fourth 10-Year Interval

===2.

Applicable Code Requirements===

Code Case N-638-4 allows for ambient temperature temper bead welding of ferritic materials without the requirement for elevated preheat or post weld heat treatment. In addition, Code Case N-638-4, paragraph 1(b), requires that the depth of the weld shall not be greater than one-half of the ferritic base metal thickness.

The NRC approved Code Case N-638-4 in Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, (Reference 5) with the following conditions:

(1) Demonstration for ultrasonic examination of the repaired volume is required using representative samples which contain construction type flaws.

(2) The provisions of 3(e)(2) or 3(e)(3) may only be used when it is impractical to use the interpass temperature measurement methods described in 3(e)(1), such as in situations where the weldment area is inaccessible (e.g., internal bore welding) or when there are extenuating radiological conditions.

The RG 1.147 conditions do not apply to the planned repair/replacement activity at Palisades as discussed in Sections 3 and 4 below. Condition (1) does not apply because radiography will be used for the required volumetric examination per the Construction Code (Reference 7). The use of radiography as a volumetric examination method complies with paragraph 4(a) of N-638-4. Condition (2) does not apply because interpass temperature 1 of 5 ATTACHMENT ENTERGY NUCLEAR OPERATIONS, INC.

PALISADES NUCLEAR PLANT RELIEF REQUEST NUMBER RR 4-19 PROPOSED ALTERNATIVE in Accordance with 10 CFR 50.55a(a)(3)(ii)

Hardship or Unusual Difficulty Without Compensating Increase in Level of Quality and Safety

1. ASME Code Component(s) Affected I Applicable Code Edition Components / Numbers:

Pressurizer Safety Relief Valve RV-1 041, weld number PCS-6-PRS-1 C1-1 Code of Record:

American Society of Mechanical Engineers (ASME)Section XI, 2001 Edition through 2003 Addenda as amended by 10 CFR 50.55a ASME Code Case N-638-4, "Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique,Section XI, Division 1,n (Reference 2)

==

Description:==

Dissimilar metal in the pressurizer safety relief valve nozzle Unit / Inspection Interval: Palisades Nuclear Plant (PNP)/ Fourth 10-Year Interval

2. Applicable Code Requirements

Code Case N-638-4 allows for ambient temperature temper bead welding of ferritic materials without the requirement for elevated preheat or post weld heat treatment. In addition, Code Case N-638-4, paragraph 1 (b), requires that the depth of the weld shall not be greater than one-half of the ferritic base metal thickness".

The NRC approved Code Case N-638-4 in Regulatory Guide (RG) 1.147, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1,n (Reference 5) with the following conditions:

(1) Demonstration for ultrasonic examination of the repaired volume is required using representative samples which contain construction type flaws.

(2) The provisions of 3(e)(2) or 3(e)(3) may only be used when it is impractical to use the interpass temperature measurement methods described in 3(e)(1), such as in situations where the weldment area is inaccessible (e.g., internal bore welding) or when there are extenuating radiological conditions.

The RG 1.147 conditions do not apply to the planned repair/replacement activity at Palisades as discussed in Sections 3 and 4 below. Condition (1) does not apply because radiography will be used for the required volumetric examination per the Construction Code (Reference 7). The use of radiography as a volumetric examination method complies with paragraph 4(a) of N-638-4. Condition (2) does not apply because interpass temperature 1 of 5

measurement will be performed by direct measurement using the provision of 3(e)(1) and will not be performed using the provisions of either 3(e)(2) or 3(e)(3).

===3.

Reason for Request===

During the current 1 R23 refueling outage, Entergy Nuclear Operations, Inc. (ENO) performed an ultrasonic examination on pressurizer safety relief valve RV-1 041 weld PCS-6-PRS-1C1-1 (RV-1041). The examination revealed two axial indications in the root area of the weld. The weld containing the indications is a dissimilar metal weld (DMW) between the pressurizer nozzle and flange for the safety relief valve. These two indications did not meet applicable acceptance criteria under ASME Section XI, Table IWB-3410, Acceptance Standards, and require a repair/replacement activity to return the weld to an acceptable condition.

In the existing design, the pressurizer safety relief valve nozzle configuration contains materials that are susceptible to primary water stress corrosion cracking (PWSCC). First, the safety relief valve weld neck flange was manufactured from SB-i 66, UNS N06600 (Alloy 600) nickel alloy while the DMW attaching the flange to the vessel nozzle was fabricated from Alloy 82/1 82 filler metal. The nozzle was manufactured from A-508, Class 2 material, and the pressurizer upper head is A-533, Grade B Class 1. The pressurizer nozzle and upper head materials are low alloy steels which are not susceptible to PWSCC. See Figure 1.

The new DMW will be installed and examined in accordance with the 1992 Edition of ASME Section III, Subsection NB. However, in lieu of the preheat and postweld heat treatment requirements of the Construction Code, ENO plans to install the Alloy 52M weld buttering across the face and full circumference of the weld end preparation of the A-508, Class 2 nozzle using the ambient temperature temper bead provisions of Code Case N-638-4.

Because Code Case N-638-4, paragraph 1(b) limits the depth of the weld to one-half of the ferritic base metal thickness, ENO will propose an alternative to this requirement in Section 4.

Hardship If this repair/replacement activity was exclusively performed in accordance with the Construction Code, then conventional postweld heat treatment, as prescribed in the Construction Code for this repair/replacement activity, would have to be performed in the field, and would result in unnecessary radiological exposure to maintenance personnel.

Resistance heating blankets would have to be attached to the relief valve nozzle and surrounding area using a capacitor discharge stud welding process. Thermocouples would also have to be attached to the relief valve nozzle using a capacitor discharge welding process to monitor postweld heat treatment temperatures. Prior to heat-up, thermal insulation would also have to be installed. Upon completion of postweld heat treatment, the insulation, heating blankets, studs, and thermocouples would have to be removed from the nozzle. Thermocouples and stud welds would be removed by grinding, and ground removal areas would be subsequently examined by the liquid penetrant or magnetic particle method.

This process would result in approximately 1 Rem of added dose as compared to the alternative.

Although Subsections IWA-4600 and IWA-4630 of ASME Section XI provide requirements for temper bead welding without postweld heat treatment, these requirements would also 2 of 5 measurement will be performed by direct measurement using the provision of 3(e)(1) and will not be performed using the provisions of either 3(e)(2) or 3(e)(3).

3. Reason for Request

During the current 1 R23 refueling outage, Entergy Nuclear Operations, Inc. (ENO) performed an ultrasonic examination on pressurizer safety relief valve RV-1041 weld PCS-6-PRS-1C1-1 (RV-1041). The examination revealed two axial indications in the root area of the weld. The weld containing the indications is a dissimilar metal weld (DMW) between the pressurizer nozzle and flange for the safety relief valve. These two indications did not meet applicable acceptance criteria under ASME Section XI, Table IWB-3410, "Acceptance Standards," and require a repair/replacement activity to return the weld to an acceptable condition.

In the existing design, the pressurizer safety relief valve nozzle configuration contains materials that are susceptible to primary water stress corrosion cracking (PWSCC). First, the safety relief valve weld neck flange was manufactured from SB-166, UNS N06600 (Alloy 600) nickel alloy while the DMW attaching the flange to the vessel nozzle was fabricated from Alloy 821182 filler metal. The nozzle was manufactured from A-508, Class 2 material, and the pressurizer upper head is A-533, Grade B Class 1. The pressurizer nozzle and upper head materials are low alloy steels which are not susceptible to PWSCC. See Figure 1.

The new DMW will be installed and examined in accordance with the 1992 Edition of ASME Section III, Subsection NB. However, in lieu of the preheat and postweld heat treatment requirements of the Construction Code, ENO plans to install the Alloy 52M weld buttering across the face and full circumference of the weld end preparation of the A-508, Class 2 nozzle using the ambient temperature temper bead provisions of Code Case N-638-4.

Because Code Case N-638-4, paragraph 1 (b) limits the depth of the weld to one-half of the ferritic base metal thickness, ENO will propose an alternative to this requirement in Section 4.

Hardship If this repair/replacement activity was exclusively performed in accordance with the Construction Code, then conventional postweld heat treatment, as prescribed in the Construction Code for this repair/replacement activity, would have to be performed in the field, and would result in unnecessary radiological exposure to maintenance personnel.

Resistance heating blankets would have to be attached to the relief valve nozzle and surrounding area using a capacitor discharge stud welding process. Thermocouples would also have to be attached to the relief valve nozzle using a capacitor discharge welding process to monitor postweld heat treatment temperatures. Prior to heat-up, thermal insulation would also have to be installed. Upon completion of postweld heat treatment, the insulation, heating blankets, studs, and thermocouples would have to be removed from the nozzle. Thermocouples and stud welds would be removed by grinding, and ground removal areas would be subsequently examined by the liquid penetrant or magnetic particle method.

This process would result in approximately 1 Rem of added dose as compared to the altemative.

Although Subsections IWA-4600 and IWA-4630 of ASME Section XI provide requirements for temper bead welding without postweld heat treatment, these requirements would also 2 of 5

involve unnecessary radiological exposure to site personnel for the same reasons as a conventional postweld heat treatment. These requirements involve elevated preheating, monitoring of interpass temperature, and a postweld hydrogen bakeout, which are accomplished and controlled using the same methods described above for a conventional postweld heat treatment. This process would also result in approximately 1 Rem of added dose as compared to the alternative.

Therefore, utilizing this proposed alternative to Code Case N-638-4 will result in a significant reduction in radiological exposure to site personnel.

===4.

Proposed Alternative and Basis for Use===

Pursuant to 10 CFR 50.55a(a)(3)(ii), ENO proposes an alternative to the provision in paragraph 1(b) of N-638-4 that limits the depth of the weld to one-half the ferritic base metal thickness. More specifically, ENO proposes to use the new alternative provision in paragraph 1 (b)(1) of N-638-5 which states:

(1) Through-wall circumferential welds are permitted if the following restrictions are met:

(a)

For repair/replacement activities associated with existing welds, the existing weld (including any associated buttering) shall be removed in its entirety.

(b)

Temper bead buttering shall be applied across the entire face of the weld preparation area on the base materials requiring tempering, and shall extend around the full circumference of the joint.

Proposed Alternative ENO will replace this existing nozzle/flange assembly with a modified design. The modification will replace the existing SB-166, Alloy 600 weld neck flange with an SA-182 F316 austenitic stainless steelfiange, which is not susceptible to PWSCC. The Alloy 82/1 82 weld material will be removed and the nozzle cut back slightly to assure that all of the original weld metal is removed. The new DMW between the stainless steel weld neck flange and low alloy steel nozzle will be made with ERNiCrFe-7A (Alloy 52M) weld metal. The weld neck flange will be slightly longer to make up for the removal of the original weld metal, but the overall length from the vessel to the safety valve bolted flanged joint will remain the same. The change is essentially like-for-like in its geometry, with only the materials being changed. The new materials are not susceptible to PWSCC. See Figure 2 for additional details.

The welding operation for the DMW, as shown in Figure 2, includes the following basic steps:

1.

Install Alloy 52M weld buttering across the entire face and circumference of the weld end preparation of the A-508, Class 2 nozzle.

2.

Install ER3O8L buffer layer and Alloy 52M buttering across the entire face and circumference of the weld end preparation of the SA-1 82, F31 6 stainless steel flange.

3.

Complete the Alloy 52M groove weld.

3 of 5 involve unnecessary radiological exposure to site personnel for the same reasons as a conventional postweld heat treatment. These requirements involve elevated preheating, monitoring of interpass temperature, and a postweld hydrogen bakeout, which are accomplished and controlled using the same methods described above for a conventional postweld heat treatment. This process would also result in approximately 1 Rem of added dose as compared to the alternative.

Therefore, utilizing this proposed alternative to Code Case N-638-4 will result in a significant reduction in radiological exposure to site personnel.

4. Proposed Alternative and Basis for Use

Pursuant to 10 CFR 50.55a(a)(3)(ii), ENO proposes an alternative to the provision in paragraph 1 (b) of N-638-4 that limits the depth of the weld to "one-half the ferritic base metal thickness." More specifically, ENO proposes to use the new alternative provision in paragraph 1 (b)(1) of N-638-5 which states:

(1) Through-wall circumferential welds are permitted if the following restrictions are met:

(a)

For repair/replacement activities associated with existing welds, the existing weld (including any associated buttering) shall be removed in its entirety.

(b)

Temper bead buttering shall be applied across the entire face of the weld preparation area on the base materials requiring tempering, and shall extend around the full circumference of the joint.

Proposed Alternative ENO will replace this existing nozzle/flange assembly with a modified design. The modification will replace the existing S8-166, Alloy 600 weld neck flange with an SA-182 F316 austenitic stainless steel flange, which is not susceptible to PWSCC. The Alloy 821182 weld material will be removed and the nozzle cut back slightly to assure that all of the original weld metal is removed. The new DMW between the stainless steel weld neck flange and low alloy steel nozzle will be made with ERNiCrFe-7A (Alloy 52M) weld metal. The weld neck flange will be slightly longer to make up for the removal of the original weld metal, but the overall length from the vessel to the safety valve bolted flanged joint will remain the same. The change is essentially like-for-like in its geometry, with only the materials being changed. The new materials are not susceptible to PWSCC. See Figure 2 for additional details.

The welding operation for the DMW, as shown in Figure 2, includes the following basic steps:

1. Install Alloy 52M weld buttering across the entire face and circumference of the weld end preparation of the A-508, Class 2 nozzle.
2. Install ER308L buffer layer and Alloy 52M buttering across the entire face and circumference of the weld end preparation of the SA-182, F316 stainless steel flange.
3. Complete the Alloy 52M groove weld.

3 of 5

Basis for Use Code Case N-638-4 and 5 specify requirements for performing ambient temperature temper bead welding using the machine gas Tungsten Arc Welding (GTAW) process. Research by the Electric Power Research Institute (EPRI) and other organizations on the use of an ambient temperature temper bead welding operation using the machine GTAW process is documented in EPRI Report GC-1 11050, Ambient Temperature Preheat for Machine GTAW Temper Bead Applications. According to the EPRI report, repair welds performed with an ambient temperature temper bead procedure utilizing the machine GTAW welding process exhibit mechanical properties equivalent or better than those of the surrounding base material. Laboratory testing, analysis, successful procedure qualifications, and successful repairs have all demonstrated the effectiveness of this process. EPRI Report GC-1 11050, Section 6.0 concluded the following:

Repair of RPV components utilizing machine GTAW temper bead welding at ambient temperature produces mechanical properties that are commonly superior to those of the service-exposed substrate. The risk of hydrogen delayed cracking is minimal using the GTAW process. Cold stress cracking is resisted by the excellent toughness and ductility developed in the weld HAZ (heat affected zone). Process design and geometry largely control restraint considerations, and these factors are demonstrated during weld procedure qualification.

ENO plans to deposit the Alloy 52M butter layers to the weld end preparation of the low alloy steel A-508, Class 2 nozzle using Code Case N-638-4. However, paragraph 1(b) of N-638-4 limits the depth of the weld to one-halt the ferritic base material thickness. The incorporation of this weld depth limitation is likely the result of concerns related to the high restraint that a repaired weld would experience if a localized or partial-depth weld repair was performed. As stresses build under a high degree of restraint, cracking may occur at detect locations.

It should be noted that paragraph 1(b) of N-638-5 also limits the depth of weld repairs to one-half the thickness of the ferritic base material. While paragraph 1(b)(1) does allow through-wall circumferential welds to be made, the following two requirements must be met:

a)

The existing weld (including any associated buttering) shall be removed in its entirety.

b) Temper bead buttering shall be applied across the entire face of the weld preparation area on the base materials requiring tempering, and shall extend around the full circumference of the joint.

The restrictions in paragraphs 1 (b)(1) of N-638-5 preclude the high restraint associated with localized and partial-depth weld repairs. Regarding the PNP pressurizer nozzle DMW, only the weld butter will be deposited with the ambient temperature temper bead rules of N-638-4. Upon completion of all welding, the DMW will be nondestructively examined in accordance with paragraph 4(a) of Code Case N-638-4. These nondestructive examinations will be performed at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third temper bead layer and will include liquid penetrant and radiographic examinations.

One other point should be considered. The provisions of Code Case N-638, and its revisions, ensure that the impact properties of the ferritic heat affected zone (HAZ) are not adversely affected when using the ambient temperature termper bead welding process.

4 of 5 Basis for Use Code Case N-638-4 and 5 specify requirements for performing ambient temperature temper bead welding using the machine gas Tungsten Arc Welding (GTAW) process. Research by the Electric Power Research Institute (EPRI) and other organizations on the use of an ambient temperature temper bead welding operation using the machine GTAW process is documented in EPRI Report GC-111 050, "Ambient Temperature Preheat for Machine GTAW Temper Bead Applications." According to the EPRI report, repair welds performed with an ambient temperature temper bead procedure utilizing the machine GTAW welding process exhibit mechanical properties equivalent or better than those of the surrounding base material. Laboratory testing, analysis, successful procedure qualifications, and successful repairs have all demonstrated the effectiveness of this process. EPRI Report GC-111050, Section 6.0 concluded the following:

"Repair of RPV components utilizing machine GTAW temper bead welding at ambient temperature produces mechanical properties that are commonly superior to those of the service-exposed substrate. The risk of hydrogen delayed cracking is minimal using the GTAW process. Cold stress cracking is resisted by the excellent toughness and ductility developed in the weld HAZ (heat affected zone). Process design and geometry largely control restraint considerations, and these factors are demonstrated during weld procedure qualification."

ENO plans to deposit the Alloy 52M butter layers to the weld end preparation of the low alloy steel A-508, Class 2 nozzle using Code Case N-638-4. However, paragraph 1 (b) of N-638-4 limits the depth of the weld to one-half the ferritic base material thickness. The incorporation of this weld depth limitation is likely the result of concerns related to the high restraint that a repaired weld would experience if a localized or partial-depth weld repair was performed. As stresses build under a high degree of restraint, cracking may occur at defect locations. It should be noted that paragraph 1 (b) of N-638-5 also limits the depth of weld repairs to one-half the thickness of the ferritic base material. While paragraph 1 (b)(1) does allow through-wall circumferential welds to be made, the following two requirements must be met:

a) The existing weld (including any associated buttering) shall be removed in its entirety.

b) Temper bead buttering shall be applied across the entire face of the weld preparation area on the base materials requiring tempering, and shall extend around the full circumference of the joint.

The restrictions in paragraphs 1 (b)(1) of N-638-5 preclude the high restraint associated with localized and partial-depth weld repairs. Regarding the PNP pressurizer nozzle DMW, only the weld butter will be deposited with the ambient temperature temper bead rules of N-638-4. Upon completion of all welding, the DMW will be nondestructively examined in accordance with paragraph 4(a) of Code Case N-638-4. These nondestructive examinations-will be performed at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third temper bead layer and will include liquid penetrant and radiographic examinations.

One other point should be considered. The provisions of Code Case N-638, and its revisions, ensure that the impact properties of the ferritic heat affected zone (HAZ) are not adversely affected when using the ambient temperature termper bead welding process.

4 of 5

That said, utilization of paragraph 1 (b)(1) of Code Case N-638-5 has no effect on the impact properties established during welding procedure qualification or create any adverse metallurgical conditions in the ferlitic HAZ. Rather, as noted above, utilization of machine GTAW temper bead welding at ambient temperature produces mechanical properties that are commonly superior to those of the service-exposed substrate.

The proposed alternative of this request provides an acceptable level of quality and safety.

The weld butter on the low alloy steel pressurizer safety valve nozzle will be installed using Alloy 52M filler metal using a qualified ambient temperature temper bead welding procedure.

The safety valve flange will be replaced with SA-1 82 F31 6 austenitic stainless steel and will be welded to the nozzle using Alloy 52M. Alloy 52M and SA-1 82 F31 6 are not susceptible to PWSCC. Except as proposed regarding paragraph 1 (b)(1) of N-638-5, ENO will comply with all other provisions of Code Case N-638-4 during the repair/replacement activity.

Therefore, ENO requests that the NRC staff authorize the proposed alternative in accordance with 10 CFR 50.55a(a)(3)(ii).

===5.

Duration of Proposed Alternative===

The proposed alternative applies to the remainder of the fourth ISI interval for PNP, scheduled to end on December 12, 2015.

6.

References 1.

ASME Code,Section XI, 2001 Edition through 2003 Addenda.

2.

ASME Section Xl, Code Case N-638-4, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique, October 5, 2006.

4.

ASME Section Xl, Code Case N-638-5, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique, April 27, 2009.

5.

Regulatory Guide 1.147, lnservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 16, October2010.

6.

ASME Section III, 1965 Edition, with Addenda through Winter 1966 7.

ASME Section III, Subsection NB, 1992 Edition/No Addenda 8.

EPRI Report GC-1 11050, Ambient Temperature Preheat for Machine GTAW Temper Bead Applications 7.

Enclosure Figure 1

- Pressurizer Safety Valve Nozzle Details Figure 2

- Safety Valve Nozzle Flange Repair/Replacement 5 of 5 That said, utilization of paragraph 1 (b)(1) of Code Case N-638-5 has no effect on the impact properties established during welding procedure qualification or create any adverse metallurgical conditions in the feriitic HAZ. Rather, as noted above, utilization of machine GTAW temper bead welding at ambient temperature produces mechanical properties that are commonly superior to those of the service-exposed substrate.

The proposed alternative of this request provides an acceptable level of quality and safety.

The weld butter on the low alloy steel pressurizer safety valve nozzle will be installed using Alloy 52M filler metal using a qualified ambient temperature temper bead welding procedure.

The safety valve flange will be replaced with SA-182 F316 austenitic stainless steel and will be welded to the nozzle using Alloy 52M. Alloy 52M and SA-182 F316 are not susceptible to PWSCC. Except as proposed regarding paragraph 1 (b)(1) of N-638-5, ENO will comply with all other provisions of Code Case N-638-4 during the repair/replacement activity.

Therefore, ENO requests that the NRC staff authorize the proposed alternative in accordance with 10 CFR 50.55a(a)(3)(ii).

5. Duration of Proposed Alternative

The proposed alternative applies to the remainder of the fourth lSI interval for PNP, scheduled to end on December 12, 2015.

6. References
1. ASME Code,Section XI, 2001 Edition through 2003 Addenda.
2. ASME Section XI, Code Case N-638-4, "Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique," October 5,2006.
4. ASME Section XI, Code Case N-638-5, "Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique," April 27, 2009.
5. Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1," Revision 16, October 2010.
6. ASME Section III, 1965 Edition, with Addenda through Winter 1966
7. ASME Section III, Subsection NB, 1992 Edition/No Addenda
8. EPRI Report GC-111050, "Ambient Temperature Preheat for Machine GTAW Temper Bead Applications"
7. Enclosure Figure 1 - Pressurizer Safety Valve Nozzle Details Figure 2 - Safety Valve Nozzle Flange Repair/Replacement 5 of 5

ENCLOSURE Figure 1 Pressurizer Safety Valve Nozzle Existing Design Flange Material; SB-I 66 Alloy 600 Weld Detail EE1 ENCLOSURE Figure 1 Pressurizer Safety Valve Nozzle Existing Design Weld Material:

Flange Material:

Alloy 82/182 S8-166 Alloy 600 Weld Detail "En ItII "i

0 I.}..

\\

II'.

t;,;t.

to Weld Detail "E" Clad Material:

ft"-t-----i A-304

[. ": I Nozzle Material:

A-508 64 Class 2 PCS-6-PRS-1 C1-1 "Nozzle to Flange Joint Weld"

ENCLOSURE Figure 2 Safety Valve Nozzle Flange Repair/Replacement NOTES 1.

REFERENCE DIMENSIONS FRON PALISADES DRAWINCI lIt-LA SHEET USA 2.

APPLICABLE ASME CODE FOR REPAIR/REPLACEMENT IS 2001 EDITiON OF ASlIlE COOS SECTION XI, WITH ADDENDA THROUCH 2003.

LOCATE FUSION LINE BETWEEN NOZZLE AND NOZZLE BUTTER. FIRST CUT SHALL BE MADE AT CENTER OF WELD TO ENSURE THAT EXCESS ORIGINAL NOZZLE MATERIAL IS NOT REMOVED.

COrUPLErLy REMOVE ORIGINAL WELO MATERIAL AND BUTTER PLUS A$ OF BASE METAL ON THE NOZZLE SIDE, 4.

MACHINED SURFACES AND SURFACES TO RE WELDED SHELL GE VISUALLY EXAMINED AND LIQUID PENETRANT EXAMINED RMGR TO WELDING INACCORDANCE WiTH AISlE CODA SECflON III, SUBSECTION NR-35.

S BUTTER SHALL BE APPliED USING AMBIENTTEMPERTXURE TEMPERBEAPTECHNIQUE PER COOS CPSE N-5384 TO ACHIEVE SUFFICIENT THICKNESS 10 ALLOW PROPER WELD FIT UP AFTER WELD PREPARAflGN IS MACNINED FINAL NOZZLE BUTTER THICKNESS SHALL BE GREATER THEN UJS.

6.

SUFFER{ITEM 61 MATERLALINALL BE ASME CODE. SECTION II SFA-59, ERSOEL CERTIFIED TO SECTION III. NB 0 THE CODE, 7.

DIMENSION APPLIES AFTER MACHINING AND/OR GRINDING WELD TO SUITABLE CONDITION FOR ROE.

WELD PREPARATiON AND FiNAL MACHINED DETAILS. AS APPLICABLE, SHALL BE PRDVIDEI)

BY INSTALLER. DIMENSION SHALL BE MEASUHED AND RECORDED.

FINAL BUTT WELD SHALL BE RADIODRAPHED AND LIQUID FTIIETRENT EXAMINED iN ACCORDANCE WITH NB-522S. IF REQUIRED A PSI UI.TRUAOIIlIC EXAMINATiON SHALL 41.50 BE PERFORMED PER SilIUiI FOR COMPLIANCE WITH THE DESIGN SPECIRCATION.

10.

FILLER METAL (ITEM 3) FOR THE NOZZLE AND AANGE GUTTER AND FILLER METAL FOR THE BUTIWBU) (lIEN 4) SHALL BE RIME CODE, SECTION II, SPA-SIR, ERNICrFs,7A (ALLOY SGMl, CERTIFIED TO SECTION III SUBSECTION NB OF THE. ASME 000!.

15.

FINAL SURFACE FINISH OF WELDS SHALL BE 250 HIN FUME OR SMOOTHER. THE WELD CROWN SHALL BE GROUND FLUSH WITH THE SURROUNDING BASS MATERIAL PART liST 1

MATERIAL SAFETY RIUEF A5O&-64 CLASS 2 2.

CLADDING STAINLESS STEEL 304 2.

BUTTER ALLOY 52M 4

WELD ALLOY 52M SMALL TONGUE 5

AND GROOVE SA-182F316 FLANGE j

BUFFER LAYER 30& STAINLESS STEEl, 22 (NOM)

STEP 1; REMOVAL OF ALL ALLOY 82/182 h FROM THE NOZZLE.

-_--.75 (NON)

TJ

+O,.

.22 (NON) 3.OO oo (REF.)

\\j___.1o (NoM)L>

(MOM)

WELD PREPARATION OF NOZZLE BUTTER 10 (NOM)

(NON)

IEE2: WELD OF BUTTER STEP 4: WELD PREPARATLON OF FLANGE BUTTER FINAL CONFLGILRATlON WELD FLANGE ENCLOSURE Figure 2 Safety Valve Nozzle Flange Repair/Replacement

.22" (NOM) mu: REMOVAL OF ALL ALLOY 82/182 ~

FROM THE NOZZlE.

V'"

03.00* ~8:gg.7 (REF.)

mf.Z: WELD OF BUTTER

[?

PART LIST MATERIAL

l.
)A';J:*MI~II:/"

A*508-64 CLASS 2

2.

CLADDING STAINLESS STEEL 304

3.

SUTTER ALLOY 52M

4.

WELD ALLOY 52M SMALL TONGUE

5.

AND GROOVE SA*I82F316 FLANGE

6.

SUFFER l A YER 308L STAINlESS STEB.

~:

WELD PREPARATION OF NOZZlE BUTTER I'>.'>.'>.'>.'>.'>.'>.'>.'>.'>. '>.1fS'i'-37.S* (NOM) ~

STEP 4: WELD PREPARATION OF FLANGE BUTTER

.22" (NOM) ct>6.00" (REF.)

I ¢3.00* +.g:g; (REF.)

(1)6.00" (REF.)

FINAL CONFIGIIRATION: WELD FLANGE NOTES

1.

REFERBICE DlMEH5IONS FROM PALISADES DRAWING M1-l.A SHEET 986.

2.

APPUCABlI! A5II! 0(1)£ FOR RI!PAlR/RS'lACSiIENT IS 2001 EDmON OF A5ME CODE SECnOH XI, WITH ADDENDA THROIICIH 2003.

~

L.OCATE FUSION LINE lli1WEEII NOZZLE AND NOUIJi BIIlTER. fiRST arr SHALL BE MADE V

AT CENTIR OF WELD TO ENSURE THAT EXCESS ORIGIIIAL NOZ2l.E MATEIIIAL IS NOT REMOVCD.

COMPLETLY REMOVE ORIGINAL WELD MATERiAl AND 8UTTER PLUS Uri" OF BAS£ MEl'AL ON THE NOZZLE SIDE.

4.

MAalIIIED SlJRFAaS AND SURFACES TO BE W!l.IlED SHALL BE VISUALLY EXAMIIIED AND UQUiO PEHETRANf EXAMINED PRlDR TO WELDING IN ACCORDANCE WITH ASME CODE, SEcnON III. SUIlSECl10H Ns.63152 *

~

BU11l!R SHAI.lSE APPUED USING AM8IDIT TEMI'!RI.lUR! lSIIPI!R8EAD TECltNlQUE V

PER COO! CASe N-63&4 TO ACHlM SUFflCfI!NT THICKNESS TO AIJ.I:IN PROPER WELD FIT UP AFTER WELD PREPARAnON IS MAaIINED. PINAL NOZZI.E BUT1'ER THICKNESS SHAll.

IE GREATER THAN 1/11".

6.

BUFFER (ITEM B) MATERIALSHAlL BE ASME CODE, SECTlON u. SfA.5.9. ER3OBL. CERTIFIED TO S£CTION nt. NB Of THE COD£.

fi:-.,. DIMENSION APPUES AFTER MACfllNlNG AND/OR GRINDING WELD TO SUITABLE V

CONDmON FOR NDE.

ra:-... YaD PREPARA110N AND RNAL MACMIIIED DETAlI.S, AS API'I..ICA8I.E. SHALL BE PROYIDED V

S'( IIISTALLER. DIMENSION SHALL BE IIIEASURIID AND RECORDED.

f9:-... ANAL IIUT1' weLD SHALL BE RADIDGRAPHED AND UQUID PENE'lRANT £XAMINIiD IN V

ACCORDANCE WITH N8-li222.lf REQUIRED A PSI ULTRASONIC EXl\\MlNAnDN SHALL AlSO BE PERFORMED PER 1I&61U(b1 FOR COIIPUANC& WITH THE OESIIJN SPECIfICATION.

10. fiLLER r.m'AL OTEM 3) f()R THE NOZZlE AND FlANGE 8IJITeR AND FIUER METAL FOR TIlE 8UTfWELD (ITEM 4) SHI<U BE ASME COD!!. SllcnON II, SPMI.:1A, eRNlCrt+7A (ALL.O'Y I12M~

CERTIFIED TO SECnDN 01, SUBSECrlON lIB OF ntE ASME ODOE.

U.

fiNAL SURFACE fINISH Of weLDS SHAll BE 250 !'IN RIllS OR SMOOTHER. THE YaD CROWlII SHALL BE GROUND FWSH WlTHTHESURROUIfDlNG!IASf MATEIIIAL.

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