View source for L-10-278, Supplemental Information Related to a Request to Incorporate the Use of Alternative Methodologies for the Development of RPV P-T Curves, and Request for Exemption from Certain Requirements Contained in 10 CFR 50.61 and 10 CFR 50, App. G

{{Adams
| number = ML102861221
| issue date = 10/08/2010
| title = Supplemental Information Related to a Request to Incorporate the Use of Alternative Methodologies for the Development of RPV P-T Curves, and Request for Exemption from Certain Requirements Contained in 10 CFR 50.61 and 10 CFR 50, App. G
| author name = Byrd K
| author affiliation = FirstEnergy Nuclear Operating Co
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000346
| license number = NPF-003
| contact person = 
| case reference number = L-10-278, TAC ME1127, TAC ME1128
| document type = Letter type:L
| page count = 5
| project = TAC:ME1127, TAC:ME1128
| stage = Supplement
}}

=Text=
{{#Wiki_filter:FENOC            -" %
Davis-Besse Nuclear Power Station 5501 N. State Route 2 FirstEnergyNuclear OperatingCompany                                                         Oak Harbor,Ohio 43449 October 8, 2010 L-1 0-278                                                            10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

==SUBJECT:==

Davis-Besse Nuclear Power Station Docket No. 50-346, License No. NPF-3 Supplemental Information Related to a Request to Incorporate the Use of Alternative Methodologies for the Development of RPV P-T Curves, and Request for Exemption from Certain Requirements Contained in 10 CFR 50.61 and 10 CFR 50, Appendix G (TAC NOS. MEl 127 AND MEl 128)
By letter dated April 15, 2009 [Agencywide Documents Access and Management System (ADAMS) Accession No. ML091130228], as supplemented by letter dated December 18, 2009 (ADAMS Accession No. ML093570103), the FirstEnergy Nuclear Operating Company (FENOC) submitted to the Nuclear Regulatory Commission (NRC) a license amendment request and, an exemption request for the Davis-Besse Nuclear Power Station (DBNPS). The proposed amendment would incorporate the use of alternate methodologies for the development of the reactor pressure vessel pressure-temperature (P-T) limit curves into the DBNPS Technical Specifications.
The proposed exemption would exempt DBNPS from certain requirements contained in 10 CFR 50.61 and 10 CFR Part 50, Appendix G.
By letter dated July 14, 2010 (ADAMS Accession No. ML101940393), the NRC staff requested additional information (RAI) on the proposed amendment to complete its review. FENOC letter dated August 26, 2010 provided the response to the RAI.
On September 3, 2010, a teleconference was held between the FENOC and NRC staffs to discuss the RAI response. During the teleconference clarifications of the RAI responses and the December 18, 2009 submittal were discussed, and are provided in the attachment.
tAN01

Davis-Besse Nuclear Power Station L-1 0-278 Page 2 of 2 There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Mr. Thomas A. Lentz, Manager- Fleet Licensing, at (330) 761-6071.
I declare under penalty of perjury that the foregoing is true and correct. Executed on October_, 2010.
Sincerely, Kendall W. Byrd Director, Site Performance Improvement

==Attachment:==

Supplemental Response To Request For Additional Information cc:   NRC Region III Administrator NRC Project Manager NRC Resident Inspector Executive Director, Ohio Emergency Management Agency, State of Ohio (NRC Liaison)
Utility Radiological Safety Board

Attachment L-10-278 Supplemental Response To Request For Additional Information Page 1 of 3 On September 3, 2010, a teleconference was conducted between the FirstEnergy Nuclear Operating Company (FENOC) and the Nuclear Regulatory Commission (NRC) staffs to discuss a Request for Additional Information (RAI) submitted by FENOC on August 26, 2010. During the teleconference, clarifications to the RAI responses and the associated license amendment request dated December 18, 2009 were discussed. The NRC staff questions are in bold, followed by the FENOC responses.
NRC Staff Question 1 The response to Question #3 of the RAI refers to a 28.770 F temperature differential between the reactor coolant and the limiting location in the reactor vessel wall. Was this temperature differential based on a 50 0 F/hour step change heatup or a 75 0F/hour step change heatup?

===Response===
The temperature differential was controlled more by the heat transfer characteristics of the fluid and metal than the heatup rate, and was essentially the same for both the 50 degrees Fahrenheit (&deg;F)/hour step change heatup and the 75 0F/hour step change heatup.
NRC Staff Question 2 What is the basis for the margin term of 4.570 F added to the temperature differential between the reactor coolant and limiting (1/4t) location in the vessel wall?

===Response===
The 4.57&deg;F term is a correction factor to reflect the difference in the temperature differential analysis performed with the adjusted reference temperature (ART) values used in the April 15, 2009 submittal and the revised ART values used in the December 18, 2009 submittal. The temperature differential would be slightly different for the two different ART values, at the reactor coolant temperature corresponding to each ART value. The 4.57&deg;F term is the difference between the ART values determined by the two different methods for the limiting material. The 4.57&deg;F would bound the actual difference between the temperature differential values for the two different ART values.

Attachment L-1 0-278 Page 2 of 3 NRC Staff Question 3 Confirm that the 28.77&deg;F temperature differential is from the reactor coolant to the 1/4t location versus the 3/4t location and that the 1/4t location is the controlling location for the DBNPS reactor vessel during heatup with respect to allowable pressure.

===Response===
The 28.77&deg;F temperature differential is the reactor coolant to the 1/4t location versus the 3/4t location. The 1/4t location is the controlling location for the DBNPS reactor vessel during heatup with respect to allowable pressure.
NRC Staff Question 4 Confirm that the chemistry factors used to calculate the ART for welds WF-182-1 and WF-233 were determined from the RG 1.99, Rev. 2 tables rather than using the minimum chemistry factor of 167 required by the staff safety evaluation of BAW-2308.

===Response===
The chemistry factors were determined using the Regulatory Guide 1.99, "RADIATION EMBRITTLEMENT OF REACTOR VESSEL MATERIALS," Revision 2 tables.
NRC Staff Question 5 Page 10 of 16 of Enclosure A to the December 18, 2009 submittal provides an uncorrected maximum pressure value of 625 psig below 235'F. This is different from the currently approved P-T curves for Davis Besse. Is the 625OF [correct unit is psig] value from the new PTLR that has not yet been submitted to the NRC?

===Response===
Yes, the 625 pounds per square inch (psig) value is the uncorrected value for the maximum pressure below 235OF from the new.PTLR. However, in the new PTLR the pressure appearing on the P-T curves will be the corrected pressure (corrected for the actual measurement location), which is lower.

Attachment L-10-278 Page 3 of 3 References
: 1. Letter from Barry S. Allen to NRC dated April 15, 2009, 

==Subject:==
 "Davis-Besse Nuclear Power Station, Unit No. 1, Docket No. 50-346, License No. NPF-3, License Amendment Request to Incorporate the Use of Alternate Methodologies for the Development of Reactor Pressure Vessel Pressure-Temperature Limit Curves, and Request for Exemption from Certain Requirements Contained in 10 CFR 50.61 and 10 CFR 50, Appendix G" (ADAMS Accession No. ML091130228).
: 2. Letter from Barry S. Allen to NRC dated December 18, 2009, 

==Subject:==
 "Davis-Besse Nuclear Power Station, Unit No. 1, Docket No. 50-346, License No. NPF-3, Supplemental Information Related to a License Amendment Request to Incorporate the Use of Alternate Methodologies for the Development of Reactor Pressure Vessel Pressure-Temperature Limit Curves, and-Request for Exemption from Certain Requirements Contained in 10 CFR 50.61 and 10 CFR 50, Appendix G (TAC No. ME1 127 - License Amendment Request, ME-1 128 Exemption Request)" (ADAMS Accession No. ML093570103).
: 3. Letter from Barry S. Allen to NRC dated August 26, 2010, 

==Subject:==
 "Davis-Besse Nuclear Power Station, Docket No. 50-346, License No. NPF-3, Response to a Request for Additional Information Related to a License Amendment Request to Incorporate the Use of Alternative Methodologies for the Development of RPV P-T Curves, and Request for Exemption from Certain Requirements Contained In 10 CFR 50.61and 10 CFR 50, Appendix G (TAC NOS. ME1127 and 1128)."}}