L-17-070, Reply to Request for Additional Information Related to License Renewal Commitment

Reply to Request for Additional Information Related to License Renewal Commitment

ML17054D480
Person / Time
Site:	Davis Besse
Issue date:	02/22/2017
From:	Boles B FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CAC MF7626, L-17-070
Download: ML17054D480 (15)

Text

FENOC' 5501 North State Route 2 RrstEnergy Nuclear Operating Company Oak Harbor. Ohio 43449 Brian D. Boles 419-321-7676 Vice President, Fax: 419-321-7582 Nuclear February 22, 2017' L-17-070 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Davis-Besse Nuclear Power Station, Unit No. 1 Docket No. 50-346, License Number NPF-3 Reply to Request for Additional Information Related to License Renewal Commitment No. 42 (CAC MF7626)

By letter dated April 21, 2016 (Agencywide Documents Access and Management, System (ADAMS) Accession No. ML16112A079), FirstEnergy Nuclear Operating Company (FENOC) submitted a Fatigue Monitoring Program evaluation for Davis-Besse Nuclear Power Station, Unit No. 1 (DBNPS), to address License Renewal Commitment 42. By letter dated September26, 2016 (ADAMS Accession No.

ML16270A447), FENOC submitted a reply to a U.S. Nuclear Regulatory Commission (NRC) request for additional information regarding FENOC's April 21, 2016 letter.

By letter dated January 23, 2017 (ADAMS Accession No. ML16364A279), the NRC requested additional information to complete its review of FENOC's Fatigue Monitoring Program evaluation. Attachment 1 provides the FENOC reply to the NRC request for additional information. Attachment 2 provides a regulatory commitment to complete fatigue evaluations for nickel-based alloys (NBA) and low-alloy steel (LAS) components and submit the evaluations. These evaluations will be submitted on or before April 28, 2017.

If there are any questions or if additional information is required, please contact Mr. Patrick McCloskey, Manager- Regulatory Compliance, at (419) 321-7274.

Davis-Besse Nuclear Power Station, Unit No. 1 L-17-070 Page2 Attachments:

1. Reply to Request for Additional Information Related to Davis-Besse Nuclear Power Station, Unit No. 1 (DBNPS), License Renewal Commitment 42

2. Regulatory Commitment List cc: NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager Utility Radiological Safety Board

Attachment 1 L-17-070 Reply to Request for Additional"lnformation (RAI) Related to Davis-Besse Nuclear Power St~tion, Unit No. 1 (DBNPS),

License Renewal Commitment 42 Page 1 of 12 By letter dated January 23, 2017 (ADAMS Accession No. ML16364A279), the NRG requested additional information to complete its review of FirstEnergy Nuclear Operating Company's (FENOC's) Fatigue Monitoring Program evaluation. The requested information is provided below. The NRG staff request is shown in bold text, followed by the FENOC reply.

NRC STAFF RAI

Background

Section 2.C(11), "License Renewal Conditions," of Renewed Facility Operating License No. NPF-3 specifies that the Commitments in Appendix A of NUREG-2193, Supplement 1, "Safety Evaluation Report Related to the l..icense Renewal of Davis-Besse Nuclear Power Station," published April 2016 (ADAMS Accession No. ML16104A350), are part of the DBNPS Updated Final Safety Analysis Report.

License renewal Commitment No. 42 in Appendix A of NUREG 2193, Supplement 1, states the following:

Enhance the Fatigue Monitoring Program to:

• Evaluate additional plant-specific component locations in the reactor coolant pressure boundary that may be more limiting than those considered in NUREG/CR-62601* This evaluation will include identification of the most limiting fatigue location exposed to reactor coolant for.each material type (i.e., [carbon steel] CS, [low-alloy steel] LAS, [stainless steel] SS, and [nickel-based alloy] NBA) and that each bounding material/location will be evaluated for the effects of the reactor coolant environment on fatigue usage. Nickel-based alloy items will be evaluated using NUREG/CR-690!>2. Submit the evaluation to the NRC 1 year prior to the period of extended operation.

Enclosure B of the licensee's letter dated June 17, 2011 (ADAMS Accession No.

ML11172A389), provides AREVA Report No. 51-9157140-001. Table 3-9 of the AREVA Report contains the environmentally-assisted fatigue (EAF) values for the NUREG/CR-6260 locations. Table 3-8 of the AREVA Report contains a summary of 1 NUREG/CR-6260, "Application of NUREG/CR-5999 Interim Fatigue Curves to Selected Nuclear Power Plant Components, dated February 1995, ADAMS Accession No. ML031480219.

2 NUREG/CR-6909 "Effect of LWR Coolant Environments on the Fatigue Life of Reactor Materials," dated February 2007.

L-17-070 Page 2 of 12 the reactor coolant system pressure boundary locations with environmentally-adjusted cumulative usage factor (CUFen) values that exceed the limit of 1.0.

In its April 21, 2016, letter, the licensee submitted the results of its evaluations associated with Commitment No. 42. The letter stated that locations were screened in accordance with the methodology of Electric Power Research Institute (EPRI) Technical Report 1024995, "Environmentally Assisted Fatigue Screening[:] Process and Technical Basis for Identifying EAF Limiting Locations," dated 2012. The letter also identified the most limiting locations for each of the four material types (i.e., CS, LAS, SS, and NBA). The CUFen values are provided for two of the four limiting locations. The CUFen values are not provided for the LAS and NBA locations. The LAS and NBA locations reference EPRI Technical Report 1024995.

By email dated August 26, 2016 (ADAMS Accession No. ML16242A008), the NRC staff requested additional information regarding the licensee's April 21, 2016, letter. The licensee responded to this request by letter dated September 26, 2016.

However, this response did not fully address the staff's request.

In the August 26, 2016, email, the NRC staff asked for the following information in Request (1 ):

Describe the plant-specific methodology and criteria used to rank locations and select the most limiting locations for EAF. Describe relevant factors for each step of the process, such as thermal zones, material types, transient complexity, temperature effects, and complexity of the systems (as applicable). Justify the use of different material types to bound locations. Justify that the process is appropriately conservative.

In addition, the NRC staff asked for the following information in Request (4):

State the locations being managed by the fatigue monitoring program to maintain the CUFen values below the limit of 1.0 through the period of extended operation. Provide the CUFen values for the locations being managed by the fatigue monitoring program.

The licensee's response to Request (1) did not justify the use of different material types to bound locations and did not justify that the process is appropriately conservative. In Table 1 of the licensee's September 26, 2016, letter, the licensee provided information regarding the screening of initial sentinel locations. The NBA and LAS locations in Table 3-9 of AREVA Report No. 51-9157140-001 are not bounded by the locations provided in Table 1 of the September 26, 2016, letter.

L-17-070 Page 3 of 12 The licensee's response to Request (4) states that Table 2 of the licensee's September 26, 2016, letter "lists the CUFen value for the components evaluated."

Table 2 appears to only include the non-NUREG/CR-6260 locations being tracked by the licensee's allowable operating transient cycle program to maintain the CUFen values below the limit of 1.0 through the period of extended operation.

Request The numbering is continued from the NRC staffs previous request for additional information issued by email dated August 26, 2016. - -

(5) a. Justify the use of different material types to bound locations.

b. Justify the elimination of NBA and LAS locations with CUFen values that are more limiting than NBA and LAS locations considered in NUREG/CR-6260.

c. Justify that the process is appropriately conservative if the allowable operating transient cycle program is tracking NBA and LAS locations that do not have the highest CUFen values and are not bounding for the respective material types.

d. Provide the list of EAF locations being tracked by the fatigue monitoring program, if it is revised. *

(6) Provide both the NUREG/CR-6260 and non-NUREG/CR-6260 locations being managed by the fatigue monitoring program to maintain the CUFen values below the limit of 1.0 through the period of extended operation. Provide the CUFen value, American Society of Mechanical Engineers Code CUF value, material type, and environmental correction factor (Fen) for each EAF location being managed by the fatigue monitoring program.

(7) License renewal Commitment No. 23 states:

In association with the time-limited aging analysis for effects of environmentally assisted fatigue of the high-pressure injection (HPI) nozzle safe end including the associated Alloy 82/182 weld (weld that connects the safe end to the nozzle), replace the HPI nozzle safe end, including the associated Alloy 82/182 weld, for all four HPI nozzles prior to the period of extended operation. Apply the Fat_igue Monitoring Program to evaluate the environmental effects and manage cumulative fatigue damage for the replacement HPI nozzle safe ends and associated welds.

In its April 21, 2016, [letter,] the licensee stated that:

Due to higher than expected dose rates, the elbows immediately upstream of the HPI nozzles were not replaced as originally planned.

L-17-070 Page 4 of 12 The evaluation performed for Commitment 42 assumed these elbows would be replaced prior to entry into the period of extended operation, and therefore would have no appreciable fatigue life. The Fatigue Monitoring Program will be applied to these elbows as part of Commitment 23 to evaluate the environmental effects and manage cumulative fatigue damage for the elbows along with the replacement HPI nozzle safe ends and associated welds. This evaluation will be complete prior to October 22, 2016, as currently documented in NUREG-2193.

By letter dated November 18, 2016 (ADAMS Accession No. ML16327A066),

the licensee stated that it had completed those activities noted in license renewal commitments applicable to DBNPS, which are part of the DBNPS Updated Final Safety Analysis Report.

Confirm that the elbows immediately upstream of the HPI nozzles impacted by the completion of Commitment No. 23 are bounded by the limiting EAF locations that are being tracked. Confirm that the plant-specific methodology and criteria used to rank locations and select the most limiting locations for EAF was consistently applied to these locations.

FENOC REPLY TO RAI (5) a. Justify the use of different material types to bound locations.

b. Justify tl:le elimination of NBA and LAS locations with CUFen values that

. are more limiting than NBA and LAS locations considered in NUREG/CR-6260.

c. Justify that the process is appropriately conservative if the allowable operating transient cycle program is tracking NBA and LAS locations that do riot have the highest CUFen values and are not bounding for the respective material types.

d. Provide the list of EAF locations being tracked by the fatigue monitoring program, if it is revised.

RESPONSE RAI (5) a - d In response to issues (5) a - c, in lieu of justifying the use of different materials to bound locations, FENOC will evaluate the limiting NBA and LAS for EAF for 60-year projected cycles. In addition, Davis-Besse plans to evaluate the remaining locations with EAF greater than 1.0 that were considered bounded by other locations. These locations were identified in FENOC Letter dated September 26, 2016 (ADAMS Accession No. ML16270A447), Table 1.

L-17-070 Page 5 of 12 See Attachment 2 to this letter for the regulatory commitment.

In response to issue (5) d, as discussed in FENOC Letter dated September 26, 2016 (ADAMS Accession No. ML16270A447), response to Question 4, all locations are being tracked by the Fatigue Monitoring Program. See Table 1 at the end of this section for the current list of EAF locations being managed by the Fatigue Monitoring Program.

(6) Provide both the NUREG/CR-6260 and non-NUREG/CR-6260 locations being managed by the fatigue monitoring program to maintain the CUFen values below the limit of 1.0 through the period of extended operation. Provide the CUFen value, American Society of Mechanical Engineers Code CUF value, material type, and environmental correction factor (Fen) for each EAF location being managed by the fatigue monitoring program.

RESPONSE RAI (6)

See Table 1 at the end of this section for the current list of Reactor Coolant System (RCS) pressure boundary components in contact with the RCS Environment being managed for EAF by the Fatigue Monitoring Program.

(7) License renewal Commitment No. 23 states:

In association with the time-limited aging analysis for effects of environmentally assisted fatigue of the high-pressure injection (HPI) nozzle safe end including the associated Alloy 82/182 weld (weld that connects the safe end to the nozzle}, replace the HPI nozzle safe end, including the associated Alloy 82/182 weld, for all four HPI nozzles prior

• to the period of extended operation. Apply the Fatigue Monitoring Program to evaluate the environmental effects and manage cumulative

• fatigue damage for the replacement HPI nozzle safe ends and associated welds.

In its April 21, 2016, [letter,] the licensee stated that:

Due to higher than expected dose rates, the elbows immediately upstream of the HPI nozzles were not replaced as originally planned.

The evaluation performed for Commitment 42 assumed these elbows would be replaced prior to entry into the period of extended operation, and therefore would have no appreciable fatigue life. The Fatigue Monitoring Program will be applied to these elbows as part of Commitment 23 to evaluate the environmental effects and manage cumulative fatigue damage for the elbows along with the replacement HPI nozzle safe ends and associated welds. This evaluation will be complete prior to October 22, 2016, as currently documented in NUREG-2193.

L-17-070 Page 6 of 12 By letter dated November 18, 2016 (ADAMS Accession No. ML16327A066),

the licensee stated that it had completed those activities noted in license renewal commitments applicable to DBNPS, which are part of the DBNPS Updated Final Safety Analysis Report.

Confirm that the elbows immediately upstream of the HPI nozzles impacted by the completion of Commitment No. 23 are bounded by the limiting EAF locations that are being tracked. Confirm that the plant-specific methodology and criteria used to rank locations and select the most limiting locations for EAF was consistently applied to these locations.

RESPONSE RAI (7)

An EAF evaluation was performed for the High Pressure Injection (HPI) Piping and elbowlet connection in accordance with NUREG/CR-5704, "Effects of LWR Coolan.t Environments on Fatigue Design Curves of Austenitic Stainless Steels."

The results of the evaluation are included in Table 1, below.

L-17-070 Page 7 of 12 Table 1: Reactor Coolant System (RCS) Components Managed by the Fatigue Monitoring Program Material Component Location CUF CUFadj Fen CUFen Notes Type RV Closure, Head LAS O.o3 2.45 0.07 RV Closure, Vessel LAS 0.02 2.45 0.05 CROM Housing, Adapter SS 0.014 15.35 0.21 CROM Housing, Body CROM Housing, Blind Flanges

. Ni-Cr-Fe SS 0.08 0.0024 4.78 15.35 0.38 0.04 CROM Housing, Motor Tube Flanges SS 0.00 15.35 0 Inlet Nozzle LAS 0.829 0.146 2.45 0.358 NUREGICR-6260 Location Outlet Nozzle LAS 0.768 0.335 2.45 0.821 NUREGICR-6260 Location Reactor Vessel Core Flood Nozzle to Safe End SS 0.064 15.34 0.982 Core Flood Nozzle LAS 0.504 2.45 0. 123 NUREGICR-6260 Location lncore Instrument Nozzles Ni-Cr-Fe 0.770 0.206 4. 16 0.857 NUREG/CR-6260 Location Segmented Skirt, Head to Skirt Structure cs 0.254 1.74 0.44 RV Shell, Nozzle Belt LAS 0.024 2.45 0.059 RV Shell, Lower Head LAS 0.024 2.45 0.059 NUREGICR-6260 Location Continuous Vent Nozzle, Reducer to Pipe Weld SS 0.001 15.35 0.02 Continuous Vent Nozzle, J-Groove Weld Ni-Cr-Fe 0.9 4.78 4.31 See Note 10 Reactor Coolant RC pump cover, cooling hole ligament SS 0.56 NIA NIA See Note 1 Pumps RC pump cover, bearing cavity SS 0.964 0.032 15.35 0.49

L-17-070 Page 8 of 12 Table 1: Reactor Coolant System (RCS) Components Managed by the Fatigue Monitoring Program, cont.

Material Component Location CUF CUFadj Fen CUFen Notes Type Spray Nozzle, Nozzle cs 0.01 1.74 0.02 Spray Nozzle, Safe End Ni-Cr-Fe 0.01 4.78 0.05 Spray Nozzle, Nozzle I Head Juncture cs 0.01 1.74 0.02 Spray Nozzle, Weld Overlay Ni-Cr-Fe 0.01 4.78 0.05 Surge Nozzle, Inside Radius cs 0.182 1.74 0.317 NUREG/CR-6260 Location Surge Nozzle, Safe End SS 0.108 0.0581 15.35 0.892 NUREG/CR-6260 Location Surge Nozzle, Piping to Safe End Weld SS 0.6 19 1.49 0.922 NUREG/CR-6260 Location Vessel Suooort Lugs, Support cs 0.01 1.74 0.02 Vessel Suooort Lugs, Shell cs 0.01 1.74 0.02 Heater Bundle Closure, Cover Plate LAS 0.05 2.45 0.123 Heater Bundle Closure, Diaphragm Plate SS 0.41 *

• 0.92 *See Note 3 Heater Bundle Closure, Seal Weld SS 0.66 *

• 0.75 *See Note 3 Pressuriz.er Shel~ Heater Belt Transition cs 0.13 1.74 0.23 3" Pressuriz.er Relief Nozzle, Nozzle cs Exempt See Note 4 3" Pressuriz.er Relief Nozzle, Safe End SS Exempt See Note 4 3" Pressuriz.er Relief Nozzle, Uooer Head cs Exempt See Note 4 Other Openings, Vent Nozzle Ni-Cr-Fe Exempt See Note 5 Other Openings, Level Sensing Nozzle (Upper) Ni-Cr-Fe Exempt See Note 5 Other Openings, Level Sensing Nozzle (Lower) Ni-Cr-Fe Exempt See Note 5 Other Openings, Level Sensing Nozzle (Lower) Opening Ni-Cr-Fe 0. 166 4.78 0.793 Other Openings, Thermowell Nozzle Ni-Cr-Fe Exempt See Note 5 Other Openings, Thennowell Nozzle Opening Ni-Cr-Fe 0.166 4.78 0.793 Other Openings, Sampling Nozzle Ni-Cr-Fe Exempt See Note 5 Other Openings, Sampling Nozzle Opening Ni-Cr-Fe 0.166 4.78 0.793 Other Openings, Manway cs Exempt See Note 5

L-17-070 Page 9 of 12 Table 1: Reactor Coolant System (RCS) Components Managed by the Fatigue Monitoring Program, cont.

Material Component Location CUF CUFadj Fen CUFen Notes Tvoe Primary Manwavs LAS 0.34 2.45 0.83 Primary Manway Diaphragm Seal Welds See Note 6 Primary Handhole Cover LAS 0.37 2.45 0.91 Primary Handhole Diaphragm Seal Weld See Note 6 Inlet Nozzle I Primary Head Juncture LAS 0.79 2.45 1.94 See Note 10 Primary Outlet Nozzles LAS 0.14 2.45 0.34 Outlet Nozzle I Primary Head Junctures LAS 0.25 2.45 0.61 Lower Primary Head away from Outlet Nozzles LAS 0.11 2.45 0.27 Steam Generators Upper Primary Head I Tubesheet Knuckle including Vent I LAS 0.28 2.45 0.69 (See Note 1) Level Sensing and Acoustic Sensor Lower Primary Head I Tubesheet Knuckle LAS 0.08 2.45 0.20 Perforated Tubesheets, Postulated Thin Ligament (Primary LAS 0.39 2.45 0.96 Side)

Lower Spherical I Flat Head Juncture LAS 0.33 2.45 0.81 Lower Flat Head LAS 0.10 2.45 0.25 Tubes Ni-Cr-Fe 0.36 4.78 1.72 See Note 10 Tube Seal Welds Ni-Cr-Fe 0.42 4.78 2.01 See Note 10 Tube Plug Seal Welds Ni-Cr-Fe 0.23 4.78 1.10 See Note 10

L-17-070 Page 10of12 Table 1: Reactor Coolant System (RCS) Components Managed by the Fatigue Monitoring Program, cont.

Material Component Location CUF CUFadj Fen CUFen Notes Type Hot Leg Piping cs 0.827 1.74 1.44 See Note 10 Uooer Cold Leg Piping cs 0.59 1.74 0. 10 Lower Cold Leg cs 0. 183 1.74 0.32 Pressurizer Surge Line, Hot Leg Surge Nozzle Inside Radius cs 0.445 1.74 0.774 NUREG/CR-6260 Location Pressurizer Surge Line, Piping Adjacent to Outboard End of Reactor Coolant SS 0.179 0.0385 9.05 0.348 NUREG/CR-6260 Location Hot Leg Surge Nozzle (End of Hot Leg Weld Overlay)

System (RCS)

Pressurizer Surge Line, Piping Elbows SS 0.6463 0.0833 11.13 0.927 NUREG/CR-6260 Location Piping Pressurizer Surge Line, Piping Straights SS 0.7658 0.0953 9.85 0.939 NUREG/CR-6260 Location Reactor Coolant Pump Discharge Nozzle SS 0.0007 15.35 0.01 Reactor Coolant Pump Suction Nozzle SS 0.0004 15.35 0.01 Spray Line Piping (Node 73) SS 0.486 9.013 4.38 See Note 10 Spray Line Piping (Node 81) SS 0.454 9.013 4.09 See Note 10 Decay Heat Nozzle cs 0.89 0.5269 1.74 0.92

L-17-070 Page 11 of 12 Table 1: Reactor Coolant System (RCS) Components Managed by the Fatigue Monitoring Program, cont.

Material Component Location CUF CUFadj Fen CUFen Notes Type HPl/MU Nozzle cs 0.226 0.271 1.74 0.472 NUREG/CR-6260 Location NUREG/CR-6260 Location HPl/MU Nozzle, Safe End including Weld SS 0.141 0.064

• 0.434

• See Note 8 Letdown Piping SS 0.604 0.04774 15.35 0.73 RC Drain Nozzles SS 0.132 0.1184

• 0.8866 *See Note 9 HPI Lines SS 0.9115 0.008 15.35 0.123 Reactor Coolant HPI Lines, Elbow let SS 0.981 0.045 15.35 0.691 System (RCS)

Core Flood Piping SS 0.582 0.23967 2.55 0.61 Piping Continuous Vent Line SS 0.0318 15.35 0.49 Core Flood Tank Discharge Check Valves SS 0.02839 15.35 0.44 Decay Heat Containment Isolation Valves SS 0.14594 0.01268 15.35 0.19 Decay Heat Bypass Containment Isolation Valves SS 0.02732 15.35 0.42 Low Pressure Injection Check Valves SS 0.14099 0.00935 15.35 0.14 Low Pressure Injection Containment Isolation Valves SS 0.18261 0.01294 15.35 0.20 Decay Heat Decay Heat Class l Piping SS 0.23303 2.55 0.595 NUREG/CR-6260 Location Piping

L-17-070 Page 12 of 12 Ta ble 1: Reacto r Coolant System (RCS) Components Managed by the Fatigue Monitoring Program, cont.

NOTES (1) Location not exposed to RCS environment, therefore not subject to EAF.

(2) Not a RCS Pressure Boundary Component.

(3) Detailed elastic and elastic-plastic analyses completed to determine adjusted usage factors. For the elastic portion of the fatigue usage, the maximum Fen factor of 15.35 is conservatively applied . For the elastic-plastic portion, a detailed Fen calculation is performed.

(4) These nozzles are shown acceptable by satisfying requirements of paragraphs N-415.1 and N-450 of ASME Section III - 1968 Edition with Summer 1968 Addenda.

(5) These nozzles are shown acceptable by satisfying the requirements of paragraph N-415.l of ASME Section III - 1968 Edition with Summer 1968 Addenda (6) Covers are sealed using gaskets and seal welds were not used, therefore fatigue calculations not required.

(7) Only primary RCS Pressure Boundary locations with CUF greater than 0.052 are evaluated for EAF.

(8) EAF CUF using integrated strain rate Fen factors.

(9) CUFen determined using NUREG/CR-6909 rules. The strain amplitude is less than the strain amplitude threshold of 0.10% in all cases, Fen does not need to be applied.

(10) These locations were considered bounded by other locations. See response to Question 5.

Attachment 2 L-17-070 Regulatory Commitment List Page 1 of 1 The followi ng list identifies those actions committed to by FirstEnergy Nuclear Operating Company (FENOC) for the Davis-Besse Nuclear Power Station , Unit No. 1 (Davis-Besse) in this document. Any other actions discussed in the submittal represent intended or planned actions by FENOC. They are described only as information and are not Regulatory Commitments. Please notify Mr. Patrick McCloskey, Manager - Regulatory Compliance, at (419) 321-7274 , of any questions regarding this document or associated Regulatory Commitments .

Regulatory Commitment Due Date

1. FENOC will evaluate the limiting nickel-based April 28, 2017 alloy (NBA) and low-alloy steel (LAS) components for environmentally-assisted fatigue (EAF) for 60-year projected cycles. In addition ,

Davis-Besse plans to evaluate the remaining locations with EAF greater than 1.0 that were considered bounded by other locations. These locations were identified in FENOC Letter dated September 26 , 2016 (ADAMS Accession No.

ML16270A447), Table 1. FENOC will submit the results of the evaluations to the Nuclear Regulatory Commission .