RS-15-292, Response to NRC Requests for Additional Information, Set 13, Dated November 3, 2015 Related to the License Renewal Application

Response to NRC Requests for Additional Information, Set 13, Dated November 3, 2015 Related to the License Renewal Application

ML15344A347
Person / Time
Site:	LaSalle
Issue date:	12/10/2015
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-15-292, TAC MF5346, TAC MF5347
Download: ML15344A347 (21)

Text

Michael P. Gallagher Vice President, License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way Kennett Square, PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-15-292 December 10, 2015 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-37 4

Subject:

Response to NRC Requests for Additional Information, Set 13, dated November 3, 2015 related to the LaSalle County Station, Units 1 and 2, License Renewal Application (TAC Nos. MF5347 and MF5346)

References:

1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon),

to NRC Document Control Desk, dated December 9, 2014, "Application for Renewed Operating Licenses"

2. Letter from Jeffrey S. Mitchell, US NRC to Michael P. Gallagher, Exelon, dated November 3, 2015, "Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 13 (TAC Nos. MF5347 and MF5346)"

3. E-mail from Jeffrey S. Mitchell, US NRC to John G. Hufnagel, Exelon, dated December 2, 2015 In Reference 1, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the LaSalle County Station (LSCS), Units 1 and 2. In Reference 2, the NRC requested additional information to support staff review of the LRA. Note that although Reference 2 indicates that a response would be provided within 30 days, Reference 3 authorized submittal of the response by December 14, 2015.

Enclosure A contains the response to this request for additional information.

Enclosure 8 contains updates to sections of the LRA affected by the response.

There are no new or revised regulatory commitments contained in this letter.

December 10, 2015 U.S. Nuclear Regulatory Commission Page 2 If you have any questions, please contact Mr. John Hufnagel, Licensing Lead, LaSalle License Renewal Project, at 610-765-5829.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on /2-IO "lO/S""

Respectfully,

~

Vice President - License Renewal Projects Exelon Generation Company, LLC

Enclosures:

A: Response to Set 13 Request for Additional Information B: LSCS License Renewal Application Updates cc: Regional Administrator- NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Project Manager, NRR-DORL- LaSalle County Station NRC Senior Resident Inspector, LaSalle County Station Illinois Emergency Management Agency - Division of Nuclear Safety

RS-15-292 Enclosure A Page 1 of 10 Enclosure A Response to Set 13 Request for Additional Information related to the LaSalle County Station (LSCS) License Renewal Application (LRA)

RAI 4.3.3-1a

RS-15-292 Enclosure A Page 2 of 10 RAI 4.3.3-1a

Background:

License renewal application (LRA) Section 4.3.3 states that the location with the highest ASME cumulative usage factor (CUF) for each material within a Class 1 system that normally contacts liquid reactor coolant will be considered limiting. The applicant defined the criteria for determining a bounded location as: a) must be affected by the same transients as the analyzed location, b) must have a lower ASME CUF than the analyzed location, and c) must be made from the same material or, if of a different material, the bounded material must have a lower environmentally assisted fatigue correction factor (Fen) value than the bounding material. The LRA further states that the environmental fatigue analyses will be managed by the Fatigue Monitoring program, which includes corrective actions that could result in revisions to the analyses. The LRA states that the environmental fatigue analyses will be reviewed and updated if necessary to ensure that the limiting locations have been satisfactorily evaluated for reactor water environmental effects.

In its response to RAI 4.3.3-1, by letter dated August 6, 2015, the applicant stated that the leading location bounds a location of a differing material for the Reactor Core Isolation Cooling (RCIC),

Residual Heat Removal (RHR) Supply and Return, Reactor Recirculation, and Reactor Water Cleanup systems. In its response, the applicant provided its justification to selecting a stainless steel location to bound a carbon steel location within the system to monitor for the effects of environmentally-assisted fatigue (EAF). In addition to the limiting location selection criteria listed above, the applicant also justified its selection by stating that the fatigue analysis for the leading location was performed using a more rigorous methodology.

Issue:

In its response, the applicant provided Table 1 and Table 2 which contain the ASME CUF -

highest location and Bounding Fen Multiplier values for stainless steel and carbon steel locations with the highest CUF values. The staff is unclear if the ASME CUF - highest location values represent the environmentally-adjusted CUF values. The staff is also unclear on how the Bounding Fen Multiplier values were calculated and why these values differ from the Fen values provided in LRA Tables 4.3.3-3 and 4.3.3-4.

Also, the applicant stated that for Unit 1, the Reactor Recirculation system, RHR Supply and Return system, and Reactor Water Cleanup system are subjected to similar transients. For Unit 2, the applicant stated that the Reactor Recirculation system and Reactor Water Cleanup system are subjected to similar transients. LRA Section 4.3.3 uses the term same when referencing transient sets. The staff is unclear if the similar transients represent the same transient set for each system.

After selecting the limiting locations for these systems, the applicant stated that the CUF values were refined based on NUREG/CR-6909 and 60-year transient cycle projections. In Table 1 and Table 2 in the applicants response to RAI 4.3.3-1, the applicant provided the ASME CUF values for the highest stainless steel and carbon steel locations. Because the applicant determined that the stainless steel locations were limiting, the applicant stated that the environmental fatigue evaluations were not performed on the bounded carbon steel locations. The staff needs additional information on how the applicant refined the ASME CUF values for the limiting locations to calculate the NUREG/CR-6909 60-year projected CUF values, to ensure that if the same

RS-15-292 Enclosure A Page 3 of 10 methodology was performed on the carbon steel locations, the resulting refinement would produce an effect on the carbon steel location which is either proportional to that for the stainless steel location or provides assurance that the stainless steel location will remain bounding. The staff needs reasonable assurance that after refinement of these ASME CUF values, the stainless steel locations would remain the limiting locations.

The LRA states that the environmental fatigue analyses will be reviewed and updated if necessary to ensure that the limiting locations have been satisfactorily evaluated for reactor water environmental effects. The staff is unclear if the applicant will review only those locations that the applicant had initially determined are limiting (locations included in LRA Tables 4.3.3-1 through 4.3.3-4) or if the applicant will re-evaluate its limiting location screening determination to ensure that locations selected are still the most limiting in the system or subsystem. If the applicant is only reviewing the environmental fatigue analyses for the locations in LRA Tables 4.3.3-1 through 4.3.3-4, the staff needs additional justification on how the applicant ensures that the limiting locations have not changed, especially accounting for systems that include different materials.

Request:

1. In reference to Table 1 and Table 2 in the response to RAI 4.3.3-1:

a) Clarify if the ASME CUF - highest location values represent the environmentally-adjusted CUF values.

b) Clarify how the Bounding Fen Multiplier values were calculated.

2. For Unit 1, clarify if the Reactor Recirculation system, RHR Supply and Return system, and Reactor Water Cleanup system are subjected to the same set of transients. For Unit 2, clarify if the Reactor Recirculation system and Reactor Water Cleanup system are subjected to the same set of transients. If not, justify that the fatigue analyses for these systems can be evaluated together when there are discrepancies in the transient input set for the fatigue analyses.

3. When performing environmental fatigue evaluations for the selected limiting locations:

a) Describe how the CLB ASME CUF values in Table 1 and Table 2 were refined to achieve the 60-year NUREG/CR-6909 CUF values represented in the LRA.

b) Justify that the methodology applied to refine the CUF values of the stainless steel locations would provide an effect on the carbon steel location which is either proportional to that for the stainless steel location or provides assurance that the stainless steel location will remain bounding.

4. When initiating corrective actions to review and update environmental fatigue analyses, clarify if the selection of limiting locations will also be evaluated and updated, as necessary. If not, justify how the applicant will ensure that the limiting locations have not changed, especially accounting for systems that include different materials. Provide any necessary updates or clarifications to the UFSAR supplement.

RS-15-292 Enclosure A Page 4 of 10 Exelon Response:

Responses to Requests:

1a. The ASME CUF values in Tables 1 and 2 in the response to RAI 4.3.3-1 are not environmentally-adjusted CUF values. These are the limiting (i.e. highest ASME CUF) values listed within the ASME Section III, Class 1 fatigue analyses for these subsystems.

1b. The bounding Fen multipliers, shown in Table 1 and Table 2 in the response to RAI 4.3.3-1, were used in justifying that the environmental fatigue analyses of certain stainless steel locations are bounding for carbon steel components within the affected subsystems. As further described in the response to Request 3b below, the methodology used to evaluate environmental fatigue will no longer credit the environmental fatigue analyses of stainless steel components to bound carbon steel components. Therefore, the comparisons shown in the Response to RAI 4.3.3-1 that were based upon these bounding Fen multipliers are no longer utilized, including the data provided in Table 1 and Table 2. However, in response to Request 1b, the following information is provided.

The following assumptions were used in developing these bounding Fen values:

When calculating the environmental multiplier for carbon steels, the sulfur content is assumed > 0.015 weight%. This conservatively maximizes the environmental multiplier.

When calculating the environmental multiplier for carbon steels, the strain rate is conservatively assumed < 0.001%/sec. This conservatively maximizes the environmental multiplier.

When calculating the environmental multiplier for stainless steel, the strain rate is conservatively assumed < 0.0004%/sec. This conservatively maximizes the environmental multiplier.

Average transient temperatures were used in computing Fen values, as permitted in NUREG/CR-6909, Appendix A, Incorporating Environmental Effects Into Fatigue Evaluations. When using average transient temperatures in computing the Fen value and when performing load-pair-specific Fen evaluations, if a minimum transient temperature is lower than the NUREG/CR-6909 threshold temperature of 302°F (150°C),

then 302°F is the minimum temperature used in computing the average . This is a conservative approach as higher temperatures can result in higher Fen values.

Computation of Bounding Stainless Steel Fen Value The computation of the bounding Fen multiplier for the Class 1 components fabricated from stainless steel is shown below. The NUREG/CR-6909 Fen equation for stainless steel provides a fixed value for transformed dissolved oxygen, O*, so this bounding Fen value is applicable to all Class 1 piping systems since there are no variables that change by system.

RS-15-292 Enclosure A Page 5 of 10

SS Fen = exp(0.734 -T*O* * ),

where:

T* = transformed service temperature, O* = transformed dissolved oxygen (DO) value, and

• = transformed strain rate, as shown below:

T* = (T-150)/175 (for temperatures 150ºC and < 325 ºC)

For Bounding SS Fen, T = maximum possible service temperature, 573ºF (300.6ºC)

T* = (300.6-150)/175 = 0.8606 O* = 0.281 for all dissolved oxygen levels (per NUREG/CR-6909), and

• = ln(0.0004/0.4) for strain rates < 0.0004%/sec (slowest) = -6.908 Thus:

Bounding SS Fen = exp(0.734 - (0.8606)(0.281)(-6.908))

Bounding SS Fen = 11.07 Computation of Bounding Carbon Steel Fen Value for RH, RR, and RT Piping Systems The computation of the bounding Fen multiplier for the Class 1 components fabricated from carbon steel that are located within the Reactor Recirculation (RR), RHR Supply and Return (RH), and Reactor Water Cleanup (RT) piping systems is shown below. The NUREG/CR-6909 equation for carbon steel includes a variable for transformed dissolved oxygen, O*, that is a function of Dissolved Oxygen (DO) content. The DO value varies by location within the reactor coolant pressure boundary and varies as a function of water chemistry controls, including the use of Hydrogen Water Chemistry and Noble Metal Chemical Addition (HWC/NMCA) to reduce oxygen content. One Fen multiplier was computed using the DO value applicable during Normal Water Chemistry (NWC) operations, when no HWC/NMCA controls are in effect. A separate Fen multiplier was computed using the DO value applicable during HWC/NMCA operations. The 60-year average Fen value for carbon steel applicable to all three of the RH, RR, and RT piping systems were determined using a weighted average based on 60-year HWC/NMCA availability projections for each unit. The NUREG/CR-6909 Fen equation for carbon steel is shown below:

CS Fen = exp(0.632 -0.101S*T*O* * ),

where:

S = Sulfur content - assumed >0.015 wt. % (most conservative assumption)

S* = 0.015 for S > 0.015 wt. %

RS-15-292 Enclosure A Page 6 of 10 T = service temperature (ºC)

T* = 0 for T <150ºC T* = (T-150) (for temperatures 150ºC and < 350ºC)

DO = dissolved oxygen (ppm)

O* = 0 for DO 0.04 ppm O* = ln(DO/0.04) (for DO > 0.04ppm and <0.5ppm)

• = ln(0.001) for strain rates < 0.001%/sec = -6.908.

For Bounding CS Fen during NWC conditions at Maximum Operating Temperature:

T = maximum service temperature, 573ºF (300.6ºC)

T* = (300.6-150) = 150.6 DO = 0.162 ppm with NWC in RR/RH/RT Piping during NWC conditions O* (NWC - RR/RH/RT Piping) = ln(0.162/0.04) = 1.3987 during NWC conditions

• = ln(0.001) for strain rates < 0.001%/sec = -6.908.

Thus:

RR/RH/RT CS Fen (NWC) = exp(0.632 -0.101S*T*O* * )

RR/RH/RT CS Fen (NWC) = exp(0.632 -(0.101)(0.015)(150.6)(1.3987)(-6.908))

RR/RH/RT CS Fen (NWC) = 17.06 For Bounding CS Fen during HWC/NMCA Conditions at Maximum Operating Temperature:

DO = 0.011 ppm with HWC/NMCA in RR/RH/RT Piping O* (HWC/NMCA - RR/RH/RT Piping) = 0

RR/RH/RT CS Fen (HWC/NMCA) = exp(0.632 -0.101S*T*O* * )

RR/RH/RT CS Fen (HWC/NMCA) = exp(0.632 -(0.101)(0.015)(150.6)(0)(-6.908))

RR/RH/RT CS Fen (HWC/NMCA) = exp(0.632)

RR/RH/RT CS Fen (HWC/NMCA) = 1.88 The overall CS Bounding Fen values were determined using a 60-year weighted average between the NWC Fen value and the HWC/NMCA Fen value, as shown below:

Unit 1 RR/RH/RT HWC/NMCA 60-year average availability = 70.2%

Unit 1 RR/RH/RT NWC 60-year average availability = 29.8%

RS-15-292 Enclosure A Page 7 of 10 Thus:

Unit 1 RR/RH/RT Piping Bounding CS Fen = (Fen-NWC x 0.298 + Fen-HWC/NMCA x 0.702)

Unit 1 RR/RH/RT Piping Bounding CS Fen = 6.40 Unit 2 RR/RH/RT HWC/NMCA 60-year average availability = 73.5%

Unit 2 RR/RH/RT NWC 60-year average availability = 26.5%

and:

Unit 2 RR/RH/RT Piping Bounding CS Fen = (Fen-NWC x 0.265 + Fen-HWC/NMCA x 0.735)

Unit 2 RR/RH/RT Piping Bounding CS Fen = 5.90 Differences Between Bounding Fen Values and Fen Values In Class 1 Piping EAF Analyses The bounding Fen multiplier values described above differ from the Fen values provided in LRA Tables 4.3.3-3 and 4.3.3-4 for several reasons, primarily related to different temperature assumptions. The assumptions for the remaining variables were unchanged from the bounding cases described above. In some cases, the temperature used as input in computing the Fen multiplier within the Class 1 piping environmental fatigue analysis for a given component is not the bounding reactor vessel maximum temperature of 573ºF (300.6ºC) shown above. The maximum operating temperature of the subsystem, which is 552ºF for the RR, RH, and RT piping systems, was used in some of the environmental fatigue analyses. However, NUREG/CR-6909, Appendix A, also permits the use of average operating temperatures in determining the Fen multipliers, which were used in some of the environmental fatigue analyses. NUREG/CR-6909, Appendix A also permits computation of individual Fen multipliers for each transient pair within the fatigue analysis. In these cases, the average temperatures for the two transients within each transient pair were used to determine the Fen value for that line in the fatigue analysis. Each transient pair in the analysis may have a different Fen value. In these cases, the Fen value shown in LRA Tables 4.3.3-3 and 4.3.3-4 is a weighted average Fen for the analysis, determined by dividing the total CUFen by the 6909 CUF value.

2. For Unit 1, the Reactor Recirculation system, RHR Supply and Return system, and Reactor Water Cleanup system are subjected to the same set of design transients. Likewise, for Unit 2, the Reactor Recirculation system, RHR Supply and Return system, and the Reactor Water Cleanup system are subjected to the same set of design transients. It should be noted that for each unit, additional environmental fatigue analyses have been completed such that the limiting location for each material in each of these systems has been evaluated separately, as shown in response 3b below.

3a. The refinements used in developing the NUREG/CR-6909 CUF values, as permitted in Appendix A of NUREG/CR-6909, consist of the following:

Using NUREG/CR-6909 fatigue curves for the applicable materials instead of the ASME Code fatigue curves.

Using the average operating temperature for the transients instead of the bounding design temperature to determine the NUREG/CR-6909 CUF value. When average

RS-15-292 Enclosure A Page 8 of 10 temperatures are used, the minimum temperature used for any transient is 302ºF (150ºC), the threshold temperature value for the NUREG/CR-6909 fatigue curve for carbon steel.

Using reduced numbers of cycles based upon the 60-year cycle projections shown in LRA Tables 4.3.1-1 and 4.3.1-2. There is an existing commitment within the Fatigue Monitoring program to impose cycle limits corresponding to the lowest numbers of cycles analyzed within the environmental fatigue analyses prior to the period of extended operation (Enhancement 1 of Commitment 43).

3b. For Unit 1 and Unit 2, the additional environmental fatigue analyses described below have been prepared in order to confirm that the environmental fatigue analyses performed for the stainless steel locations previously determined to be limiting are in fact bounding for all carbon steel components within the applicable systems. These additional environmental fatigue analyses have been prepared for limiting carbon steel locations within piping systems that were considered bounded by environmental fatigue analyses of stainless steel components. These additional analyses confirm that the environmental fatigue analyses for the limiting stainless steel locations bound the carbon steel components within these piping systems. The results of these additional analyses are added to LRA Tables 4.3.3-3 and 4.3.3-4, as shown in Enclosure B.

With the generation of these additional environmental fatigue analyses for carbon steel locations, the limiting location for each material within the Class 1 piping systems affected by the same transients has now been separately evaluated for environmental fatigue. Therefore, there is no longer a need to credit the environmental fatigue analyses prepared for stainless steel components to bound carbon steel components. LRA Section 4.3.3 is revised to delete reference to the bounding of one material with the environmental fatigue analysis of another material, as shown in Enclosure B.

Unit 1 For Unit 1, additional environmental fatigue analyses have been prepared so that each system has at least one environmental fatigue analysis for each material within the system, as described below. An additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 1RR-01, Node 302, which is bounding for all carbon steel components in the Unit 1 RR piping system. The resulting CUFen value for Node 302 is 0.445. An additional environmental fatigue analysis has been prepared for the limiting stainless steel location in subsystem 1RR-01, Node Y71, which is bounding for all stainless steel components in the Unit 1 RR piping system. The resulting CUFen value for Node Y71 is 0.823. These new results are added to LRA Table 4.3.3-3, as shown in Enclosure B.

For Unit 1, the environmental fatigue analysis of the limiting stainless steel location in subsystem 1RH-01, Node 55, has been revised to account for a small increase in fatigue usage associated with a locked snubber that was evaluated in a revision to the ASME fatigue analysis. The resulting CUFen value for Node 55 is 0.977, as shown in the revised LRA Table 4.3.3-3 in Enclosure B.

RS-15-292 Enclosure A Page 9 of 10 For Unit 1, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 1RH-01, Node 295B, which is bounding for all carbon steel components in the Unit 1 RH piping system. The resulting CUFen value for Node 295B is 0.691. This new carbon steel limiting location is added to LRA Table 4.3.3-3, as shown in Enclosure B.

For Unit 1, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 1RT-05, Node (Data Point) 10, which is bounding for all carbon steel components in the Unit 1 RT piping system. The resulting CUFen value for Node 10 is 0.077. These new results are added to LRA Table 4.3.3-3, as shown in Enclosure B.

For Unit 1, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in the Reactor Core Isolation Cooling system (RI), subsystem 1RI-03, Node 10A, which is bounding for all carbon steel components within the RI piping system. The resulting CUFen value for Node 10A is 0.823. These new results are added to LRA Table 4.3.3-3, as shown in Enclosure B.

Unit 2 For Unit 2, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 2RR-01, Node 455, which is bounding for all carbon steel components in the Unit 2 RR piping system. The resulting CUFen value for Node 455 is 0.2315.

This new carbon steel limiting location has been added to LRA Table 4.3.3-4, as shown in Enclosure B. The limiting stainless steel location within the Unit 2 RR piping system, Node B390, was previously evaluated, as shown in LRA Table 4.3.3-4.

For Unit 2, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 2RH-08, Node 336, which is bounding for all carbon steel components in the Unit 2 RH piping system. The resulting CUFen value for Node 336 is 0.5460.

This new carbon steel limiting location is added to LRA Table 4.3.3-4, as shown in Enclosure B.

For Unit 2, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 2RT-05, Node 830, which is bounding for all carbon steel components in the Unit 2 RT piping system. The resulting CUFen value for Node 830 is 0.2065.

These new results are added to LRA Table 4.3.3-4, as shown in Enclosure B.

For Unit 2, an additional environmental fatigue analysis has been prepared for the limiting carbon steel location in subsystem 2RI-03, Node (Data Point) 10A, which is bounding for all carbon steel components within the Unit 2 RI piping system. The resulting CUFen value for Node 10A is 0.8484. These new results are added to LRA Table 4.3.3-4, as shown in Enclosure B.

Note: A typographical error was corrected in LRA Table 4.3.3-2, as shown in Enclosure B.

RS-15-292 Enclosure A Page 10 of 10 Conclusion The additional environmental fatigue analyses performed for the limiting carbon steel locations within the systems described above confirm that the environmental fatigue analyses of the stainless steel locations are bounding for the carbon steel components. However, since the limiting carbon steel locations have now been satisfactorily evaluated for environmental fatigue, there is no longer a need to credit the stainless steel locations as bounding. Therefore, LRA Section 4.3.3 is revised to delete reference to the bounding of one material with the environmental fatigue analysis of another material, as shown in Enclosure B. LRA Tables 4.3.3-3 and 4.3.3-4 and the applicable notes are also revised to delete the bounding comparisons for dissimilar materials and to clarify the materials associated with individual node points, as shown in Enclosure B. The environmental fatigue analysis results presented in LRA Tables 4.3.3-3 and 4.3.3-4 demonstrate that the limiting location for each material type within each Class 1 piping system/subsystem group affected by the same transients has been satisfactorily evaluated for environmental fatigue in accordance with NUREG/CR-6909 methodology.

4. When initiating corrective actions to review and update environmental fatigue analyses, the selection of limiting locations will also be evaluated and updated, as necessary. The existing implementing procedure states that the sample of locations qualified for environmental fatigue must continue to bound the remaining locations in the reactor coolant pressure boundary that are not evaluated for reactor water environmental effects. LRA Appendix A, Section A.3.1.1 (i.e. the UFSAR Supplement), and LRA Appendix B, Section B.3.1.1 are revised to clarify that the corrective action confirms that either the locations analyzed for environmental fatigue remain limiting or, if a new limiting location is identified, it is also analyzed for environmental fatigue.

RS-15-292 Enclosure B Page 1 of 9 Enclosure B LSCS License Renewal Application Updates Resulting from the Response to the following RAI:

RAI 4.3.3-1a Note: To facilitate understanding, portions of the LRA have been repeated in this Enclosure, with revisions indicated. Previously submitted information (e.g., LRA, RAI responses) is shown in normal font. Changes due to this submittal are highlighted with bolded italics for inserted text and strikethroughs for deleted text.

RS-15-292 Enclosure B Page 2 of 9 As a result of the response to RAI 4.3.3-1a, provided in Enclosure A of this letter, the second complete paragraph of the TLAA Evaluation subsection of LRA Section 4.3.3 on LRA page 4-78, is revised as follows:

4.3.3 ENVIRONMENTAL FATIGUE ANALYSES FOR RPV AND CLASS 1 PIPING The Fen factors were applied to the 60-year CUF values and the resulting 60-year CUFen values do not exceed the design Code limit of 1.0, as shown in Tables 4.3.3-1 through 4.3.3-4. The NUREG/CR-6260 locations are noted in the tables. In several cases, a single RPV location was analyzed for environmental fatigue, but the analysis also represents another RPV location that is bounded. Likewise, in some cases, one Class 1 piping location was evaluated for environmental fatigue but the analysis also represents another piping location that is bounded.

The bounded location must be affected by the same transients as the analyzed location, must have a lower ASME CUF than the ASME CUF value of the analyzed location, and must either be made from the same material or, if of a different material, the bounded material must have a lower Fen value than the bounding material. Notes are provided below each table providing the basis for the bounding determination when applicable.

RS-15-292 Enclosure B Page 3 of 9 As a result of the response to RAI 4.3.3-1a, provided in Enclosure A of this letter, LRA Tables 4.3.3-3 and 4.3.3-4, starting on LRA page 4-87, and associated notes are revised as follows:

Table 4.3.3-3 LSCS Unit 1 - Class 1 Piping System Environmental Fatigue Analysis Results Piping System Location Node Material 60-Year Fen CUFen 6909 CUF Reactor Recirculation Piping Socket Weld Y71 Stainless 0.430 1.91 0.823 1RR (note 3) Steel Reactor Recirculation Piping 1RR- Socket Weld 302 Carbon 0.178 2.50 0.445 01 - (note 3) Steel N/A N/A Bounded by 1RH-01 Piping (note 11)

Low Pressure Core Spray Injection RPV Nozzle 5 Carbon 0.105 8.36 0.878 Piping 1LP (note 4) Steel High Pressure Core Spray Injection RPV Nozzle 5 Carbon 0.019 8.37 0.159 Piping 1HP (note 4) Steel RHR Supply and Return Piping Valve End 55 Stainless 0.315 3.10 0.977 1RH (note 5) Steel 0.308 3.04 0.937 (note 14)

RHR Supply and Return Piping Elbow 295B Carbon 0.311 2.22 0.691 1RH (note 5) Steel Feedwater 1FW (note 6) RPV Safe End A100 Carbon 0.413 1.89 0.776 Steel Standby Liquid Control (SLC) Elbow 70 Stainless 0.226 2.08 0.471 1SC-02 Steel Reactor Core Isolation Cooling 6 Sch 120160 10A Carbon 0.223 3.69 0.823 1RI-03 LR Elbow Steel N/A N/A Bounded by RPV N7 Head Spray Nozzle Outer Flange (note 12)

Reactor Water Cleanup Piping Center Line Data Carbon 0.012 6.40 0.077 1RT-05 Run Pipe Point 10 Steel N/A N/A Bounded by Branch 1RH-01 Connection Piping (note 13)

RS-15-292 Enclosure B Page 4 of 9 Notes 3 - 6: These notes correspond to component listings 3 - 6 specified in NUREG/CR-6260, Section 5.6 (Reference 4.8.13) for the Class 1 piping locations in a Newer Vintage General Electric Plant.

Note 11: (Not used) The carbon steel Node 302 in analysis 1RR-01 has an ASME CUF value of 0.673, which is bounded by the ASME CUF value of 0.954 for the stainless steel Node 55 in analysis 1RH-01. Since the ASME CUF value is higher and since the Fen multiplier for stainless steel is higher than the multiplier for carbon steel, the environmental fatigue analysis for the 1RH-01 piping system bounds the 1RR-01 piping system.

Note 12: (Not used) Thecarbon steel Node 10A in analysis 1RI-03 has an ASME CUF value of 0.912, based upon an ASME NB-3600 fatigue analysis. This carbon steel pipe elbow is welded to the stainless steel N7 Head Spray Nozzle Outer Flange that has an ASME CUF value of 0.91 for Node 376IJ that is based upon an ASME NB 3200 analysis with a finite element model. Since the degree of rigor is higher for the NB-3200 analysis and since the Fen multiplier for stainless steel is higher than the Fen multiplier for carbon steel in this system, the stainless steel flange Node 376IJ was selected as the limiting location. The environmental fatigue analysis for Node 366 of the stainless steel Unit 1 N7 Head Spray nozzle provided in LRA Table 4.3.3-1 bounds the Unit 1 carbon steel RCIC piping system. Node 366 in the environmental fatigue analysis is the same inside surface location as Node 376IJ in the CLB ASME fatigue analysis.

Note 13: (Not used) The carbon steel Node 10 in analysis 1RT-05 has an ASME CUF value of 0.012, which is bounded by the ASME CUF value of 0.954 for the stainless steel Node 55 in analysis 1RH-01. Since the ASME CUF value is higher and since the Fen multiplier for stainless steel is higher than the multiplier for carbon steel, the environmental fatigue analysis for the 1RH-01 piping system bounds the 1RT-05 piping system.

Note 14: The environmental fatigue analysis of stainless steel node 55, Valve End, in subsystem 1RH-01 was revised to account for additional fatigue usage associated with a locked snubber evaluated in a revision to the ASME fatigue analysis.

RS-15-292 Enclosure B Page 5 of 9 Table 4.3.3-4 LSCS Unit 2 - Class 1 Piping System Environmental Fatigue Analysis Results Piping System Location Node Material 6909 6909 CUFen CUF Fen Reactor Recirculation Piping - 2RR-01 SW Half B390 Stainless 0.2866 3.36 0.9625

- (note 3) Coupling Steel (Note 17)

Reactor Recirculation Piping - SW Valve 455 Carbon 0.0943 2.46 0.2315 2RR (note 3) Steel Low Pressure Core Spray Injection RPV Nozzle Node 5 Carbon N/A N/A Bounded by Piping - 2LP (note 4) Safe End Steel RPV N5 LPCS Nozzle, Safe End-to-Piping Weld, Carbon Steel Point 22 (note 13)

High Pressure Core Spray Injection RPV Nozzle Data Carbon N/A N/A Bounded by Piping - 2HP-01 (note 4) Safe End Point 5 Steel the RPV N16 HPCS Nozzle, Safe End-to-Piping Weld, Carbon Steel Point 22 (note 14)

RHR Supply and Return Piping - 2RH- Valve End 55 Stainless 0.2004 2.98 0.5969 01 - (note 5) Steel RHR Supply and Return Piping - Socket 336 Carbon 0.2505 2.18 0.5460 2RH (note 5) Weld Steel Feedwater Piping - 2FW (note 6) Half A113 Carbon 0.4180 1.88 0.7858 Coupling Steel Reactor Water Cleanup Suction Piping Valve End 830 Carbon 0.035 5.90 0.2065 2RT-05 Steel N/A N/A Bounded by 2RR-01 Reactor Recirculation Suction Piping, (note 15)

Standby Liquid Control (SLC) Piping - Elbow 320 Stainless 0.1300 2.08 0.2704 2SC-01C Steel Reactor Core Isolation Cooling Piping - 6 Sch 120 Data Carbon 0.1932 4.39 0.8484 2RI-03 Short Point Steel N/A N/A Bounded by Radius 10A RPV N7 Elbow nozzle (note 16)

RS-15-292 Enclosure B Page 6 of 9 Notes 3 - 6: These notes correspond to component listings 3 - 6 specified in NUREG/CR-6260, Section 5.6 (Reference 4.8.13) for the Class 1 piping locations in a Newer Vintage General Electric Plant.

Note 13: The carbon steel location Node 05 in analysis 2LP-01 has an ASME CUF value of 0.276, which is bounded by the carbon steel N5 RPV nozzle carbon steel safe end-to-pipe weld, Node point 22, which has an ASME CUF value of 0.323. Therefore, the environmental fatigue analysis of the N5 nozzle safe end-to-pipe weld provided in Table 4.3.3-2 is bounding for the 2LP-01 Unit 2 LP piping system.

Note 14: The carbon steel location Node (Data Point) 5 in analysis 2HP-01 has an ASME CUF value of 0.165, which is bounded by the carbon steel N16 RPV nozzle carbon steel safe end-to-pipe weld, Node point 22, which has an ASME CUF value of 0.323. Therefore, the environmental fatigue analysis of the N16 RPV nozzle safe end-to-pipe weld provided in Table 4.3.3-2 is bounding for the 2HP-01 Unit 2 HP piping system.

Note 15: (Not used) The carbon steel Node 830 in analysis 2RT-05 has an ASME CUF value of 0.036, which is bounded by the ASME CUF value of 0.716 for the stainless steel Node B390 in analysis 2RR-01. Since the ASME CUF value is higher and since the Fen multiplier for stainless steel is higher than the multiplier for carbon steel, the environmental fatigue analysis for the 2RR-01 piping system bounds the 2RT-01 piping system.

Note 16: (Not used) The carbon steel Node 10A in analysis 2RI-03 has an ASME CUF value of 0.837, based upon an ASME NB-3600 fatigue analysis. This carbon steel pipe elbow is welded to the stainless steel N7 Head Spray Nozzle Outer Flange that has an ASME CUF value of 0.91 for Node 376IJ that is based upon an ASME NB-3200 analysis with a finite element model. Since the degree of rigor is higher for the ASME NB-3200 analysis and since the Fen multiplier for stainless steel is higher than the Fen multiplier for carbon steel in this system, the stainless steel flange Node 376IJ was selected as the limiting location. The environmental fatigue analysis for Node 366 of stainless steel Unit 2 N7 Head Spray nozzle provided in LRA Table 4.3.3-2 bounds the Unit 2 carbon steel RCIC piping system. Node 366 in the environmental fatigue analysis is the same inside surface location as Node 376IJ in the CLB ASME fatigue analysis.

Note 17: (Not used) There are stainless steel and carbon steel components present within the Unit 2 Reactor Recirculation piping subsystem 2RR-01. The stainless steel component with the highest ASME CUF value within the system is Node B390, which has a CUF value of 0.716. The carbon steel component with the highest ASME CUF value is Node 455, which has an ASME CUF value of 0.418. Since the ASME CUF value is higher for stainless steel Node B390 and since the Fen multiplier for stainless steel is higher than the Fen multiplier for carbon steel in this system, Node B390 was selected as the limiting location within this system and the environmental fatigue analysis for stainless steel Node B390 is bounding for the carbon steel and stainless steel components within the system.

RS-15-292 Enclosure B Page 7 of 9 In the process of responding to RAI 4.3.3-1a, a typographical error was identified in LRA Table 4.3.3-2 on LRA page 4-85 in the Node column for the N16 High Pressure Core Spray- Safe End-to-Piping Weld. The table is revised as follows:

Table 4.3.3-2 LSCS Unit 2 - (CB&I) Reactor Pressure Vessel (RPV) Environmental Fatigue Analysis Results RPV Component Node Material 60-year 6909 60-year 6909 CUF Fen CUFen N11 Core P Nozzle N/A Nickel Alloy 0.1933 3.75 0.7245 N12, N13, and N14 Instrument Nozzles N/A N/A N/A N/A Bounded by N19 CRD Penetration (note 8)

N15 Drain Nozzle N/A N/A N/A N/A Bounded by N4 Feedwater Nozzle (note 9)

N16 High Pressure Core Spray - Safe Point 22 N/A Carbon Steel 0.1006 3.58 0.3598 End-to-Piping Weld - (note 4)

N16 High Pressure Core Spray Nozzle - Point 3 Low Alloy 0.0021 3.95 0.0083 Forging - (note 4) Steel N16 High Pressure Core Spray Nozzle - N/A Low Alloy 0.1945 5.02 0.9758 Nozzle / Vessel Intersection - (note 4) Steel N16 High Pressure Core Spray Nozzle - Point 13 Nickel Alloy 0.3148 2.84 0.8950 Thermal Sleeve - (note 4)

N16 High Pressure Core Spray Nozzle - Point 16 Stainless 0.0868 4.80 0.1766 Thermal Sleeve - (note 4) Steel N17 Seal Leak Detection Nozzle N/A N/A N/A N/A Not Analyzed for Cyclic Operation (note 10)

N19 CRD Penetration N/A Stainless 0.1733 5.26 0.9118 Steel N19 CRD Penetration - N/A Nickel Alloy 0.1275 3.75 0.4778 Stub Tube-to-Vessel Weld N20 In-Core Housing Penetration Element 152 Stainless 0.067 9.26 0.6360 Steel

RS-15-292 Enclosure B Page 8 of 9 As a result of the response to RAI 4.3.3-1a, provided in Enclosure A of this letter, Appendix A, Section A.3.1.1, Fatigue Monitoring, on LRA page A-44, fourth paragraph, is revised as follows:

A.3.1.1 Fatigue Monitoring Environmental fatigue analyses have been prepared for the limiting locations within the Unit 1 and Unit 2 reactor pressure vessels and for ASME Class 1 piping systems. In some cases, reduced numbers of cycles were analyzed, based on 60-year projections that justify the reduced numbers of cycles. The Fatigue Monitoring program will be enhanced by incorporating the most limiting numbers of cycles for each transient type used in the environmental fatigue analyses as administrative cycle limits. If an administrative cycle limit is approached, corrective actions are triggered, which may include revision of the affected environmental fatigue calculations and an expansion of the sample of locations evaluated for environmental fatigue, if warranted. The corrective action confirms that either the locations analyzed for environmental fatigue remain limiting or, if a new limiting location is identified, it is also analyzed for environmental fatigue.

RS-15-292 Enclosure B Page 9 of 9 As a result of the response to RAI 4.3.3-1a, provided in Enclosure A of this letter, Appendix B, Section B.3.1.1, Fatigue Monitoring, LRA page B-182, fourth paragraph of the Program Description, is revised as follows:

B.3.1.1 Fatigue Monitoring Program Description Environmental fatigue analyses have also been prepared for the limiting locations within the Unit 1 and Unit 2 reactor pressure vessels and for ASME Class 1 piping systems. In some cases, reduced numbers of cycles were analyzed, based on 60-year projections that justify the reduced numbers of cycles. The Fatigue Monitoring program will be enhanced by incorporating the most limiting numbers of cycles for each transient type as administrative cycle limits. If an administrative cycle limit is approached, corrective actions are triggered, which may include revision of the affected environmental fatigue calculations and an expansion of the sample of locations evaluated for environmental fatigue if warranted. The corrective action confirms that either the locations analyzed for environmental fatigue remain limiting or, if a new limiting location is identified, it is also analyzed for environmental fatigue.