ML15030A005

NRR E-mail Capture - RAI Regarding Pressure and Temperature Limits Reports (Ptlrs), Byron Station, Units 1 and 2

ML15030A005
Person / Time
Site:	Byron
Issue date:	01/29/2015
From:	Joel Wiebe Plant Licensing Branch III
To:	Gackstetter S Exelon Corp
References
Download: ML15030A005 (2)

Text

NRR-PMDAPEm Resource From: Wiebe, Joel Sent: Thursday, January 29, 2015 5:18 PM To: Nrccorrespondence-braidwood@exeloncorp.com Cc: Dwi Murray

Subject:

RAI Regarding Pressure and Temperature Limits Reports (PTLRs), Byron Station, Units 1 and 2 Steven Gackstetter, By letter dated February 13, 2014, (ADAMS Accession No. ML14044A019), Exelon Generation (the licensee) provided Pressure and Temperature Limits Reports (PTLRs), Byron Station, Units 1 and 2 to the U.S.

Nuclear Regulatory Commission (NRC) staff in accordance with Technical Specifications 5.6.6 for Byron Station, Units 1 and 2. Additional information is required to complete our review of this information.

Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix G requires that pressure-temperature (P-T) limits be developed to bound all ferritic materials in the reactor vessel (RV). Further, Sections I and IV.A of 10 CFR Part 50, Appendix G specify that all ferritic reactor coolant pressure boundary (RCPB) components outside of the RV must meet the applicable requirements of American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section III, Rules for Construction of Nuclear Facility Components.

As clarified in Regulatory Information Summary (RIS) 2014-11, Information on Licensing Applications for Fracture Toughness Requirements for Ferritic Reactor Coolant Pressure Boundary Components (ADAMS Accession No. ML14149A165), reactor vessel materials with the highest reference temperature may not always produce the most limiting P-T limits because the consideration of stress levels from structural discontinuities (such as nozzles) may produce a lower allowable pressure.

RAI Describe how the P-T limit curves for Byron Units 1 and 2 consider all ferritic pressure boundary components of the reactor vessel that are predicted to experience a neutron fluence exposure greater than 1x1017 n/cm2 (E

> 1 MeV) at the end of the licensed operating period.

If the current P-T limit curves do not consider all ferritic pressure boundary components of the reactor vessel that are predicted to experience a neutron fluence exposure greater than 1x1017 n/cm2 (E > 1 MeV) at the end of the licensed operating period, provide appropriately revised P-T limit curves to the NRC as required by Technical Specification 5.6.6.

A response is requested by March 2, 2015. If you have any questions regarding this matter, contact Joel S.

Wiebe at 301-415-6606 or by e-mail to Joel.Wiebe@nrc.gov.

1

Hearing Identifier: NRR_PMDA Email Number: 1839 Mail Envelope Properties (1A97AE0578A58B46BC77AA0B5DBD720201249964B4B7)

Subject:

RAI Regarding Pressure and Temperature Limits Reports (PTLRs), Byron Station, Units 1 and 2 Sent Date: 1/29/2015 5:17:48 PM Received Date: 1/29/2015 5:17:00 PM From: Wiebe, Joel Created By: Joel.Wiebe@nrc.gov Recipients:

"Dwi Murray" <Putri.Kusumawatimurray@exeloncorp.com>

Tracking Status: None "Nrccorrespondence-braidwood@exeloncorp.com" <Nrccorrespondence-braidwood@exeloncorp.com>

Tracking Status: None Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 2359 1/29/2015 5:17:00 PM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: