1CAN061401, Unit 1, Response to Request for Additional Information Regarding Proposed Exemption for Alternative Initial Reference Temperature Values

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Unit 1, Response to Request for Additional Information Regarding Proposed Exemption for Alternative Initial Reference Temperature Values
ML14177A302
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 06/26/2014
From: Pyle S
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
1CAN061401, TAC MF3700
Download: ML14177A302 (7)
v • d • e


Text

Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4704 Stephenie L. Pyle Manager, Regulatory Assurance Arkansas Nuclear One 1CAN061401 June 26, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852

SUBJECT:

Response to Request for Additional Information Regarding Proposed Exemption for Alternative Initial Reference Temperature Values Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. DPR-51

REFERENCES:

1. Entergy letter dated March 20, 2014, Request for Exemption from Certain 10 CFR 50.61 and 10 CFR 50, Appendix G Requirements (1CAN031403) (ML14083A640)
2. NRC letter dated June 4, 2014, Arkansas Nuclear One, Unit 1 -

Request for Additional Information Regarding Proposed Exemption for Alternative Initial Reference Temperature Values (TAC No. MF3700)

(ML14148A382)

Dear Sir or Madam:

By letter dated March 20, 2014 (Reference 1), Entergy Operations, Inc. (Entergy) submitted an exemption request for Arkansas Nuclear One, Unit 1 (ANO-1). The exemption request is from certain requirements in 10 CFR 50.61, "Fracture toughness requirements for protection against pressurized thermal shock events," and 10 CFR 50, Appendix G, "Fracture Toughness Requirements," for the proposed use of alternative initial reference temperature values for Linde 80 welds used in fabricating the ANO-1 reactor vessel.

The NRC has reviewed the submittal and has determined that in order for the staff to complete its review of the exemption, additional information is required. The purpose of this submittal is to provide the requested response. The response is attached.

This letter contains no new regulatory commitments.

1CAN061401 Page 2 of 2 If you have any questions or require additional information, please contact me.

Sincerely, ORIGINAL SIGNED BY DAVID B. BICE FOR STEPHENIE S. PYLE SLP/rwc

Attachment:

Response to Request for Additional Information Exemption Request Regarding Alternative Initial Reference Temperature Values for Certain Welds cc: Mr. Marc L. Dapas Regional Administrator U. S. Nuclear Regulatory Commission, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Peter Bamford MS O-8B3 One White Flint North 11555 Rockville Pike Rockville, MD 20852

Attachment to 1CAN061401 Response to Request for Additional Information Exemption Request Regarding Alternative Initial Reference Temperature Values for Certain Welds

Attachment to 1CAN061401 Page 1 of 4 Response to Request for Additional Information Exemption Request Regarding Alternative Initial Reference Temperature Values for Certain Welds By letter dated March 20, 2014 (Agencywide Documents Access and Management System Accession No. ML14083A640), Entergy Operations, Inc., submitted an exemption request for Arkansas Nuclear One, Unit 1 (ANO-1). The exemption is relating to use of alternative initial reference temperature values for Linde 80 welds used in fabricating the ANO-1 reactor vessel. In order for the U.S. Nuclear Regulatory Commission (NRC) staff to complete its review of the exemption, a response to the following request for additional information is requested.

1. The request dated March 20, 2014, does not explain values of chemistry factor which are used to calculate the reference temperature (RTNDT). The NRC needs this information to ensure that the RTNDT calculation is in accordance with the conditions and limitations in Topical Report BAW-2308, Revision 1-A and 2-A, Initial RTNDT of Linde 80 Weld Materials, regarding chemistry factors. Please provide the values of chemistry factor used along with the detailed calculation for RTNDT.

Entergy Response:

The following information is related to the pressurized thermal shock calculation (i.e., the fluence is calculated at the clad / base metal interface. The only difference between the determination of the RTNDT for the adjusted reference temperature and the PTS value is where the fluence is determined. The chemistry factor is not impacted by the fluence factor.

The chemistry factor and the determination of RTNDT are provided in this attachment for all of the ANO-1 reactor vessel material for completeness. The forgings and plates are not impacted by the request for the exemption to use BAW-2308.

The determination of RTNDT is provided below.

RTNDT is the mean value of the adjustment in reference temperature caused by irradiation and is calculated per 10 CFR 50.61 or Regulatory Guide (RG) 1.99, Revision 2 (same methodology) as follows:

RTNDT = (CF) x (FF) (1) where CF is the Chemistry Factor and FF is the fluence factor.

The CF is a function of the materials copper (Cu) and nickel (Ni) content (Cu weight percent (wt%) and Ni wt%, respectively). When determining the CF, the Cu wt% and Ni wt% are best estimate values for the material, which are normally the mean of the measured values for the material when available.

Attachment to 1CAN061401 Page 2 of 4 The Cu and Ni contents for the ANO-1 reactor vessel (RV) beltline materials are reported in BAW-2313. The Cu wt% and Ni wt% values for the forgings and plates are from measured data reported on the ANO-1 RV materials certified material test reports (CMTRs). The Cu wt% and Ni w% values for the Linde 80 welds are statistically determined best estimates for each weld wire heat.

The CF is determined from Table 1 (for weld metals) and Table 2 (for base metals) in 10 CFR 50.61. Linear interpolation is permitted. Using Linde 80 weld metal initial RTNDT from BAW-2308 requires a minimum CF of 167.0.

Table 1 lists the chemistry factors for the ANO-1 RV beltline materials.

Table 1: 10 CFR 50.61 Chemistry Factors for the ANO-1 RV Materials Material Identification Cu wt% Ni wt% Chemistry Factor Beltline Materials (ID)/Acceptance [Note A] [Note A] [Note B]

No.

Lower Nozzle Belt Forging AYN 131 0.03 0.70 20.0 Upper Shell Plate 1 C5120-2 0.17 0.55 122.75 Upper Shell Plate 2 C5114-2 0.15 0.52 105.6 Lower Shell Plate 1 C5120-1 0.17 0.55 122.75 Lower Shell Plate 2 C5114-1 0.15 0.52 105.6 LNBF to US Circ. Weld WF-182-1 0.24 0.63 177.95 US 1 to US 2 Axial Welds (2) WF-18 0.19 0.57 167.0 US to LS Circ. Weld WF-112 0.27 0.59 182.55 LS 1 to LS 2 Axial Welds (2) WF-18 0.19 0.57 167.0 US = Upper Shell LNBF = Lower Nozzle Belt Forging LS = Lower Shell Circ. = Circumferential Notes:

A. The reported Cu wt% and Ni wt% values for beltline forgings and plates are from measured data; the reported Cu wt% and Ni wt% values for beltline welds are weld-wire heat best estimates.

B. The Chemistry Factor is calculated per 10 CFR 50.61 or RG 1.99, Revision 2 Tables 1 and 2 (linear interpolation allowed) with a minimum of 167.0 for Linde 80 weld metals per BAW-2308.

Attachment to 1CAN061401 Page 3 of 4 In accordance with 10 CR 50.61, the FF is determined as follows:

FF = f(0.28 - 0.10logf) (2) where f (1019 n/cm2, E > 1.0 MeV) is the projected peak fluence at the clad / base metal interface.

The projected peak fluence value was determined using the methodology provided in BAW-2241-P-A..

Table 2 lists the FFs for the ANO-1 RV beltline materials at 54 Effective Full Power Years (EFPY).

Table 2: Fluence Factors at 54 EFPY for the ANO-1 RV Materials 54 EFPY Peak Material Fluence Beltline Materials Fluence ID Factor (1019 n/cm2)

Lower Nozzle Belt Forging (start of 12" thickness) AYN 131 0.113 0.442 Lower Nozzle Belt Forging (start of 8.44" thickness) AYN 131 0.142 0.491 Lower Nozzle Belt Forging (at LNBF to US Weld ) AYN 131 1.21 1.053 Upper Shell Plate 1 C5120-2 1.34 1.081 Upper Shell Plate 2 C5114-2 1.34 1.081 Lower Shell Plate 1 (8.44" thickness) C5120-1 1.32 1.077 Lower Shell Plate 2 (8.44" thickness) C5114-1 1.32 1.077 LNBF to Upper Shell Circumferential Weld WF-182-1 1.21 1.053 US 1 to US 2 Axial Welds (2) WF-18 1.06 1.016 Upper Shell to Lower Shell Circumferential Weld WF-112 1.28 1.069 LS 1 to LS 2 Axial Welds (2) WF-18 1.14 1.037 LNBF = Lower Nozzle Belt Forging US = Upper Shell LS = Lower Shell

Attachment to 1CAN061401 Page 4 of 4 The RTNDT values are calculated by multiplying the chemistry factors and fluence factors.

The 54 EFPY RTNDT values for the ANO-1 RV beltline materials are presented in Table 3.

Table 3: RTNDT Values for the ANO-1 RV Materials at 54 EFPY Beltline Materials Material ID CF FF RTNDT (°F)

Lower Nozzle Belt Forging (start of 12" thickness) AYN 131 20.0 0.442 8.8 Lower Nozzle Belt Forging (start of 8.44" thickness) AYN 131 20.0 0.491 9.8 Lower Nozzle Belt Forging (at LNBF to US Weld) AYN 131 20.0 1.053 21.1 Upper Shell Plate 1 C5120-2 122.75 1.081 132.7 Upper Shell Plate 2 C5114-2 105.6 1.081 114.2 Lower Shell Plate 1 (8.44" thickness) C5120-1 122.75 1.077 132.2 Lower Shell Plate 2 (8.44" thickness) C5114-1 105.6 1.077 113.8 LNBF to Upper Shell Circumferential Weld WF-182-1 177.95 1.053 187.4 US 1 to US 2 Axial Welds (2) WF-18 167.0 1.016 169.7 Upper Shell to Lower Shell Circumferential Weld WF-112 182.55 1.069 195.1 LS 1 to LS 2 Axial Welds (2) WF-18 167.0 1.037 173.1 LNBF = Lower Nozzle Belt Forging US = Upper Shell LS = Lower Shell

°F = degrees Fahrenheit

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