Entergy Nuclear Operations, Inc.

______

Palisades Nuclear Plant

t 27780 Blue Star Memorial HighwayCovert, Ml 49043-9530Tel 269 764 2000

Anthony J VitaleSite Vice President

PNP 2014-075

July 30, 2014

U. S. Nuclear Regulatory CommissionATTN: Document Control DeskWashington, DC 20555-0001

SUBJECT: Response to Request for Additional Information - Palisades - RR 4-17,Proposed Alternative, Request for Relief from Immediate ASME CodeFlaw Repair of Service Water System Manual Valve MV-SW135 - MF3192

Palisades Nuclear PlantDocket 50-255License No. DPR-20

REFERENCES: 1. Entergy Nuclear Operations, Inc. letter, PNP 2013-082, ReliefRequest Number 4-17, Proposed Alternative, Request for Relieffrom Immediate ASME Code Flaw Repair of Service Water SystemManual Valve MV-SW135, dated December 3, 2013 (ADAMSAccession No. ML13339A740)

2. NRC e-mail, Request for Additional Information - Palisades —

RR 4-17, Proposed Alternative, Request for Relief from ImmediateASME Code Flaw Repair of Service Water System Manual ValveMV-S W135 - MF3192, dated June 9, 2014 (ADAMS Accession No.ML14160A915)

Dear Sir or Madam:

In Reference 1, Entergy Nuclear Operations, Inc. (ENO) requested Nuclear RegulatoryCommission (NRC) approval of the Request for Relief for a Proposed Alternative for thePalisades Nuclear Plant (PNP). This Request for Relief was submitted because athrough-wall flaw was discovered in a service water system, 4-inch cast carbon steelvalve body within an ASME Class 3 system.

In Reference 2, the Nuclear Regulatory Commission (NRC) issued a request foradditional information (RAI). The response to the RAI is provided in the attachment.

This submittal contains no proprietary information.

• ~Entergy

PNP 2014-075

July 30, 2014

U. S. Nuclear Regulatory Commission AnN: 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: Response to Request for Additional Information - Palisades - RR 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135 - MF3192

Palisades Nuclear Plant Docket 50-255 License No. DPR-20

REFERENCES: 1. Entergy Nuclear Operations, Inc. letter, PNP 2013-082, Relief Request Number 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135, dated December 3, 2013 (ADAMS Accession No. ML13339A740)

2. NRC e-mail, Request for Additional Information - Palisades-

Dear Sir or Madam:

RR 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135 - MF3192, dated June 9,2014 (ADAMS Accession No. ML 14160A915)

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). This Request for Relief was submitted because a through-wall flaw was discovered in a service water system, 4-inch cast carbon steel valve body within an ASME Class 3 system.

In Reference 2, the Nuclear Regulatory Commission (NRC) issued a request for additional information (RAI). The response to the RAI is provided in the attachment.

This submittal contains no proprietary information.

PNP 201 4-075Page 2 of 2

This submittal makes no new commitments or revisions to previous commitments.

Sincerely,

ajv/jse

Attachment: 1. Response to Request for Additional Information - Palisades - RR 4-17,Proposed Alternative, Request for Relief from Immediate ASME CodeFlaw Repair of Service Water System Manual Valve MV-SW135 -

MF3192

cc: Administrator, Region Ill, USNRCProject Manager, Palisades, USNRCResident Inspector, Palisades, USNRC

PNP 2014-075 Page 2 of 2

This submittal makes no new commitments or revisions to previous commitments.

Sincerely,

ajv/jse

Attachment: 1. Response to Request for Additional Information - Palisades - RR 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135-MF3192

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

ATTACHMENT 1

Response to Request for Additional Information - Palisades - RR 4-17,Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair

of Service Water System Manual Valve MV-SWi 35 - MF3192

By letter dated December 3, 2013 (Reference 1), Entergy Nuclear Operations, Inc.(ENO) requested relief from certain requirements of American Society of MechanicalEngineers Boiler and Pressure Vessel Code (ASME Code), Section Xl, IWD-3000 whichestablished flaw size acceptance standards and provides analytical evaluation criteria.ENO proposed an alternative to the NRC conditionally approved Code Case N-51 3-3 totemporarily accept a through wall flaw in a moderate energy Class 3 valve.

In order to complete the review, the Nuclear Regulatory Commission (NRC) requestedadditional information as identified in the following request for additional information(RAI) questions (Reference 2).

1. Entergy Nuclear Operations, Inc. letter, PNP 2013-082, Relief Request Number4-17, Proposed Alternative, Request for Relief from Immediate ASME Code FlawRepair of Seivice Water System Manual Valve MV-SW135, dated December 3,2013 (ADAMS Accession No. ML13339A740)

2. NRC e-mail, Request for Additional Information - Palisades — RR 4-17, ProposedAlternative, Request for Relief from Immediate ASME Code Flaw Repair ofService Water System Manual Valve MV-S W135 - MF3192, dated June 9, 2014(ADAMS Accession No. ML1 41 60A91 5)

Nuclear Regulatory Commission (NRC) Request

1. Discuss the actual size of the pin hole in the MV-5W135 valve. Discuss the wallthickness at and around the ph hole.

Entergy Nuclear Operations, Inc (ENO) Response

1. The size of the pin hole in service water system manual valve MV-SW135 wasnot measured or calculated, although, judging from its measured leak rate of 3.5mL per minute, it was very small. The wall thickness in the vicinity of the leakwas measured by ultrasonic testing (UT) at the time the leak was discovered onOctober 25, 2013. The pin hole was encompassed by weld inspection pointsAPO1 and AQO1 and valve body inspection points APO2 and AQO2 (see UTexamination records for the weld and the valve body in the operability evaluationin Attachment 3 of the relief request). The measured wall thicknesses at weldinspection points APO1 and AQO1 were 0.256 inches and 0.215 inches,respectively. The measured wall thicknesses at valve body inspection pointsAPO2 and AQO2 were 0.672 inches and 0.692 inches, respectively. Theminimum wall thickness measured in the vicinity of the pin hole was at weld

Page 1 of 6

ATTACHMENT 1

Response to Request for Additional Information - Palisades - RR 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair

of Service Water System Manual Valve MV-SW135 - MF3192

By letter dated December 3, 2013 (Reference 1), Entergy Nuclear Operations, Inc. (ENO) requested relief from certain requirements of American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section XI, IWD-3000 which established flaw size acceptance standards and provides analytical evaluation criteria. ENO proposed an altemative to the NRC conditionally approved Code Case N-513-3 to temporarily accept a through wall flaw in a moderate energy Class 3 valve.

In order to complete the review, the Nuclear Regulatory Commission (NRC) requested additional information as identified in the following request for additional information (RAI) questions (Reference 2).

1. Entergy Nuclear Operations, Inc. letter, PNP 2013-082, Relief Request Number 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135, dated December 3, 2013 (ADAMS Accession No. ML 13339A740)

2. NRC e-mail, Request for Additional Information - Palisades - RR 4-17, Proposed Alternative, Request for Relief from Immediate ASME Code Flaw Repair of Service Water System Manual Valve MV-SW135 - MF3192, dated June 9,2014 (ADAMS Accession No. ML 14160A915)

Nuclear Regulatory Commission (NRC) Request

1. Discuss the actual size of the pin hole in the MV-SW135 valve. Discuss the wall thickness at and around the pin hole.

Entergy Nuclear Operations, Inc (ENO) Response

1. The size of the pin hole in service water system manual valve MV-SW135 was not measured or calculated, although, judging from its measured leak rate of 3.5 mL per minute, it was very small. The wall thickness in the vicinity of the leak was measured by ultrasonic testing (UT) at the time the leak was discovered on October 25,2013. The pin hole was encompassed by weld inspection points AP01 and A001 and valve body inspection points AP02 and A002 (see UT examination records for the weld and the valve body in the operability evaluation in Attachment 3 of the relief request). The measured wall thicknesses at weld inspection points AP01 and A001 were 0.256 inches and 0.215 inches, respectively. The measured wall thicknesses at valve body inspection points AP02 and A002 were 0.672 inches and 0.692 inches, respectively. The minimum wall thickness measured in the vicinity of the pin hole was at weld

Page 1 of 6

inspection point AOO1, which was 0.102 inches (see UT examination records forthe weld in the operability evaluation in Attachment 3 of the relief request).

UT thickness measurements were taken again on November21, 2013 and onDecember 19, 2013. The table below provides the thickness measurementstaken for these inspection points on these dates.

Table —Inspection Point Thickness Measurements (inches)

Weld Weld Valve Body Valve Body WeldDate Inspection Inspection Inspection Inspection Inspection

Point Point Point Point PointAPO1 AQO1 APO2 AQO2 AQOl

10/25/13 0.256 0.215 0.672 0.692 0.10211/21/13 0.251 0.211 0.675 0.699 0.10912/19/13 0.224 0.208 0.710 0.710 0.104

Pin Hole Leak

Page 2 of 6

inspection point A001 , which was 0.102 inches (see UT examination records for the weld in the operability evaluation in Attachment 3 of the relief request).

UT thickness measurements were taken again on November 21,2013 and on December 19, 2013. The table below provides the thickness measurements taken for these inspection points on these dates.

Table -Inspection Point Thickness Measurements (inches)

Weld Weld Valve Body Valve Body Weld Date Inspection Inspection Inspection Inspection Inspection

Point Point Point Point Point AP01 A001 AP02 A002 A001

10/25/13 0.256 0.215 0.672 0.692 0.102 11/21/13 0.251 0.211 0.675 0.699 0.109 12119/13 0.224 0.208 0.710 0.710 0.104

Pin Hole Leak

Page 2 of 6

NRC Request

2. Section 5 of the relief request states that “...the requested Code relief shall beused until Code repair/replacement activities are performed on the valve bodyeither during the next scheduled outage or when the predicted flaw size exceedsacceptance criteria...” (a) Clarify exactly what is meant by “Coderepair/replacement activities are performed on the valve body”. Does this meanthat a new valve will replace the degraded valve or repair only the original valvebody? If only the valve body is repaired, discuss how this can be performed perthe ASME Code, Section XI. (b) Discuss the flaw size that would exceed theacceptance criteria.

ENO Response

2. a) As discussed in the ENO relief request, the “Code repair/replacement activity”was to replace the valve. The valve was replaced in February 2014 duringrefueling outage 1 R23, as planned.

b) The flaw size that would exceed the acceptance criteria would be a flawlength greater than the allowable flaw lengths provided in Section 4.0 inStructural Integrity Associates, Inc. Report Number 1301385.401, “FlawTolerance Evaluation of Leaking MV-SW135 Service Water Valve Body,”which is contained within Attachment 3 of Reference 1. See additionaldiscussion under RAI question #5 below.

NRC Request

3. Page 5 of the Operability Evaluation report in the December 3, 2013 submittalstates that “... As a result of this Condition Report, a plan to detect cavitationthrough UT examinations and replace components with identified wall thinning asnecessary is being developed...” (a) Discuss whether this plan has beendeveloped. If yes, provide the detail of how the cavitation will be detected andwhat is the inspection frequency. If not, when will the plan will be complete. (b)Discuss the compensatory measures to mitigate the cavitation at the subjectvalve to prevent future degradation. (c) Page 14 of the Operability Evaluationreport states that under Long Term Actions, “Work Order 365955-0 1 will replaceMV-SW135 in the next refueling outage (1R23)...” Discuss how cavitation will bemitigated in the subject valve and associated piping system as a long term actionbecause the valve replacement does not mitigate the root cause of thedegradation (i.e. cavitation).

ENO Response

3. a) The cavitation inspection and replacement plan has been developed andimplemented. Cavitation damage will be identified by conducting UT

Page 3 of 6

NRC Request

2. Section 5 of the relief request states that " ... the requested Code relief shall be used until Code repair/replacement activities are performed on the valve body either during the next scheduled outage or when the predicted flaw size exceeds acceptance criteria ... " (a) Clarify exactly what is meant by IICode repair/replacement activities are performed on the valve body". Does this mean that a new valve will replace the degraded valve or repair only the original valve body? If only the valve body is repaired, discuss how this can be performed per the ASME Code, Section XI. (b) Discuss the flaw size that would exceed the acceptance criteria.

ENO Response

2. a) As discussed in the ENO relief request, the "Code repair/replacement activity" was to replace the valve. The valve was replaced in February 2014 during refueling outage 1 R23, as planned.

b) The flaw size that would exceed the acceptance criteria would be a flaw length greater than the allowable flaw lengths provided in Section 4.0 in Structural Integrity Associates, Inc. Report Number 1301385.401, "Flaw Tolerance Evaluation of Leaking MV-SW135 Service Water Valve Body," which is contained within Attachment 3 of Reference 1. See additional discussion under RAI question #5 below.

NRC Request

3. Page 5 of the Operability Evaluation report in the December 3,2013 submittal states that " ... As a result of this Condition Report, a plan to detect cavitation through UT examinations and replace components with identified wall thinning as necessary is being developed ... " (a) Discuss whether this plan has been developed. If yes, provide the detail of how the cavitation will be detected and what is the inspection frequency. If not, when will the plan will be complete. (b) Discuss the compensatory measures to mitigate the cavitation at the subject valve to prevent future degradation. (c) Page 14 of the Operability Evaluation report states that under Long Term Actions, "Work Order 365955-01 will replace MV-SW135 in the next refueling outage (1 R23) ... " Discuss how cavitation will be mitigated in the subject valve and associated piping system as a long term action because the valve replacement does not mitigate the root cause of the degradation (i.e. cavitation).

ENO Response

3. a) The cavitation inspection and replacement plan has been developed and implemented. Cavitation damage will be identified by conducting UT

Page 3 of 6

inspections to detect localized wall thinning at locations designated ascavitation-susceptible by a component cavitation risk ranking plan.Susceptible locations include locations downstream of throttle valves andorifices, locations where there is significant differential pressure, and locationswhere there is high velocity. Inspections will be prioritized based on therelative susceptibility of locations to cavitation degradation, and will take intoaccount plant operating experience, input from system hydraulic analyticalmodels, and risk of component failure. Inspection frequencies will be basedon inspection results and aforementioned factors, and will be conservativelychosen.

b) Compensatory measures to mitigate the effect of cavitation-induced erosionuntil the valve was replaced were not taken based on the expected materialloss rate and the short time duration remaining until valve replacement. Inlieu of mitigating actions, daily visual inspections and monthly UT inspectionswere conducted to validate the flaw analysis until valve replacement.

c) In lieu of eliminating the source of cavitation, the subject carbon steel valvewas replaced with a stainless steel valve in February 2014 during ascheduled refueling outage. Stainless steel is less susceptible tocavitation-induced erosion than carbon steel. Elsewhere, carbon steelcomponents that have been designated for replacement per the cavitationplan will be replaced with stainless steel components as well. Componentsreplaced under this plan will continue to be monitored, via UT inspections, forcavitation degradation under the site inspection program. Replacement ofcarbon steel components with stainless steel components is a commonindustry practice to mitigate the erosion of components due to cavitation.

NRC Request

4. Page 11 of the Operability Evaluation report states that “. .. Per section 3.2(b) [ofcode case N-513-3J the minimum wall thickness (tmin) to maintain designrequirements was calculated to be 0.020 inches...” The NRC staff finds that thetmin equation in Section 3.2(b) of Code Case N-513-3 may not be adequate andapplicable to a valve that experiences known cavitation. The corrosion rate ofcavitation can be unpredictable and aggressive. Discuss whether 0.020 incheswas used as an acceptable criterion to permit the valve to remain in service.

ENO Response

4. The 0.020 inches minimum wall thickness was not used as an acceptancecriterion for valve operability. Wall thickness was an input assumption in theevaluation that developed the through-wall flaw size acceptance criteria inSection 4.0 in Structural Integrity Associates, Inc. Report Number 1301385.401,“Flaw Tolerance Evaluation of Leaking MV-SW135 Service Water Valve Body,”

Page 4 of 6

inspections to detect localized wall thinning at locations designated as cavitation-susceptible by a component cavitation risk ranking plan. Susceptible locations include locations downstream of throttle valves and orifices, locations where there is significant differential pressure, and locations where there is high velocity. Inspections will be prioritized based on the relative susceptibility of locations to cavitation degradation, and will take into account plant operating experience, input from system hydraulic analytical models, and risk of component failure. Inspection frequencies will be based on inspection results and aforementioned factors, and will be conservatively chosen.

b) Compensatory measures to mitigate the effect of cavitation-induced erosion until the valve was replaced were not taken based on the expected material loss rate and the short time duration remaining until valve replacement. In lieu of mitigating actions, daily visual inspections and monthly UT inspections were conducted to validate the flaw analysis until valve replacement.

c) In lieu of eliminating the source of cavitation, the subject carbon steel valve was replaced with a stainless steel valve in February 2014 during a scheduled refueling outage. Stai'nless steel is less susceptible to cavitation-induced erosion than carbon steel. Elsewhere, carbon steel components that have been designated for replacement per the cavitation plan will be replaced with stainless steel components as well. Components replaced under this plan will continue to be monitored, via UT inspections, for cavitation degradation under the site inspection program. Replacement of carbon steel components with stainless steel components is a common industry practice to mitigate the erosion of components due to cavitation.

NRC Request

4. Page 11 of the Operability Evaluation report states that " ... Per section 3.2(b) [of code case N-513-3] the minimum wall thickness (tmin) to maintain design requirements was calculated to be 0.020 inches ... " The NRC staff finds that the tmin equation in Section 3.2(b) of Code Case N-513-3 may not be adequate and applicable to a valve that experiences known cavitation. The corrosion rate of cavitation can be unpredictable and aggressive. Discuss whether 0.020 inches was used as an acceptable criterion to permit the valve to remain in service.

ENO Response

4. The 0.020 inches minimum wall thickness was not used as an acceptance criterion for valve operability. Wall thickness was an input assumption in the evaluation that developed the through-wall flaw size acceptance criteria in Section 4.0 in Structural Integrity Associates, Inc. Report Number 1301385.401, "Flaw Tolerance Evaluation of Leaking MV-SW135 Service Water Valve Body,"

Page 4 of 6

which is contained within Attachment 3 of Reference 1. Since wall thickness wasan input assumption in the flaw size acceptance criteria evaluation, UT wallthickness measurements were used to validate conformance with evaluationassumptions.

The relief request states that replacement of MV-SW135 shall be performed nolater than when the predicted flaw size from either periodic inspection or by flawgrowth analysis exceeds the flaw size acceptance criteria, or the next refuelingoutage, whichever comes first.

As noted in the operability evaluation and the report, even if the actual wear rateexceeded the predicted wear rate, the ASME Code margins for MV-SW135 aremaintained as long as the degraded area with thickness below 0.102 inches isbounded by the corresponding allowable through-wall flaw lengths described inSection 4.0.

NRC Request

5. In the flaw evaluation by Structural Integrity Associates, lnc, Table 3 (page 9 of11) presents the allowable and critical flaw lengths with respect to the three valveuniform thickness. Based on Table 3 data, if the valve uniform thickness isreduced to 0.051 inches, the allowable circumference and axial flaw length are0.41 inches and 0.96 inches, respectively. It is not clear to the NRC staff howthese acceptance criteria will be used to disposition the pin hole in the subjectvalve. (a) If the valve thickness is not less than 0.051 inches but the pin holeextends to more than 0.41 inches, would the pin hole exceed the acceptancecriteria? (b) If the valve thickness is reduced to below 0.051 inches but thepin hole diameter is not more than 0.41 inches, would the valve be acceptable forservice? (c) Where should the valve thickness be measured to meet the 0.051inch criteria, i.e., at the pin hole or anywhere in the valve body? (d) Section 4 ofthe flaw evaluation states that “...ln addition, an allowable throughwallcircular opening of 1.5 inches resulted from a branch reinforcement evaluation...”How can this allowable through wall circular opening of 1.5 inches be used todisposition any pin hole expansion with respect to the allowable flaw length listedin Table 3. That is, which allowable flaw length dominates or governs for thedisposition of the pin hole in the valve?

ENO Response

5. a) If the valve thickness is 0.05 1 inches or greater and the pin hole diameterexceeds 0.41 inches in the circumferential direction, then the ASME Codestructural margin would not be met.

b) If the valve thickness is below 0.051 inches, then the evaluation would not beapplicable. Valve thicknesses below 0.051 inches were not evaluated. In this

Page 5 of 6

which is contained within Attachment 3 of Reference 1. Since wall thickness was an input assumption in the flaw size acceptance criteria evaluation, UT wall thickness measurements were used to validate conformance with evaluation assumptions.

The relief request states that replacement of MV-SW135 shall be performed no later than when the predicted flaw size from either periodic inspection or by flaw growth analysis exceeds the flaw size acceptance criteria, or the next refueling outage, whichever comes first.

As noted in the operability evaluation and the report, even if the actual wear rate exceeded the predicted wear rate, the ASME Code margins for MV-SW135 are maintained as long as the degraded area with thickness below 0.102 inches is bounded by the corresponding allowable through-wall flaw lengths described in Section 4.0.

NRC Request

5. In the flaw evaluation by Structural Integrity Associates, Inc, Table 3 (page 9 of 11) presents the allowable and critical flaw lengths with respect to the three valve uniform thickness. Based on Table 3 data, if the valve uniform thickness is reduced to 0.051 inches, the allowable circumference and axial flaw length are 0.41 inches and 0.96 inches, respectively. It is not clear to the NRC staff how these acceptance criteria will be used to disposition the pin hole in the subject valve. (a) If the valve thickness is not less than 0.051 inches but the pin hole extends to more than 0.41 inches, would the pin hole exceed the acceptance criteria ? (b) If the valve thickness is reduced to below 0.051 inches but the pin hole diameter is not more than 0.41 inches, would the valve be acceptable for service? (c) Where should the valve thickness be measured to meet the 0.051 inch criteria, i.e., at the pin hole or anywhere in the valve body? (d) Section 4 of the flaw evaluation states that " .. . In addition, an allowable throughwall circular opening of 1.5 inches resulted from a branch reinforcement evaluation ... " How can this allowable through wall circular opening of 1.5 inches be used to disposition any pin hole expansion with respect to the allowable flaw length listed in Table 3. That is, which allowable flaw length dominates or governs for the disposition of the pin hole in the valve?

ENO Response

5. a) If the valve thickness is 0.051 inches or greater and the pin hole diameter exceeds 0.41 inches in the circumferential direction, then the ASME Code structural margin would not be met.

b) If the valve thickness is below 0.051 inches, then the evaluation would not be applicable. Valve thicknesses below 0.051 inches were not evaluated. In this

Page 5 of 6

situation, either a new evaluation to support continued valve service would berequired or the valve would have to be removed from service.

c) The valve thickness should be measured to meet the 0.05 1 inch criteria inareas known to be thinned due to cavitation-induced erosion, such as nearthe pin hole leak.

d) The minimum flaw length given governs. The allowable through-wall openingof 1.5 inches is based on a branch reinforcement evaluation for a valve bodythat is 0.102 inches thick. So, this length would govern for the axial direction(i.e., 1.5 inches versus the 2.11 inches allowable calculated using the planarapproach). For the circumferential direction, the 1.23 inches allowable flawlength that was calculated using the planar approach would govern.

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situation, either a new evaluation to support continued valve service would be required or the valve would have to be removed from service.

c) The valve thickness should be measured to meet the 0.051 inch criteria in areas known to be thinned due to cavitation-induced erosion, such as near the pin hole leak.

d) The minimum flaw length given governs. The allowable through-wall opening of 1.5 inches is based on a branch reinforcement evaluation for a valve body that is 0.102 inches thick. So, this length would govern for the axial direction (Le., 1.5 inches versus the 2.11 inches allowable calculated using the planar approach). For the circumferential direction, the 1.23 inches allowable flaw length that was calculated using the planar approach would govern.

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