[Federal Register Volume 72, Number 127 (Tuesday, July 3, 2007)]
[Notices]
[Pages 36512-36514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-12855]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-280 and 50-281]


Virginia Electric And Power Company Surry Power Station, Unit 
Nos. 1 and 2; Exemption

1.0 Background

    The Virginia Electric and Power Company (the licensee) is the 
holder of Renewed Facility Operating License Nos. DPR-32 and DPR-37 
which authorize operation of the Surry Power Station, Unit Nos. 1 and 2 
(Surry 1 and 2). The license provides, among other things, that the 
facility is subject to all rules, regulations, and orders of the 
Nuclear Regulatory Commission (NRC, the Commission) now or hereafter in 
effect.
    The facility consists of two pressurized-water reactors located in 
Surry County, Virginia.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), Part 50, 
Appendix G requires that fracture toughness requirements for ferritic 
materials of pressure-retaining components of the reactor coolant 
pressure boundary of light water nuclear power reactors need to provide 
adequate margins of safety during any condition of normal operation, 
including anticipated operational occurrences and system hydrostatic 
tests, to which the pressure boundary may be subjected over its service 
lifetime; and Section 50.61 provides fracture toughness

[[Page 36513]]

requirements for protection against pressurized thermal shock (PTS) 
events. By letter dated June 13, 2006 (Agencywide Documents Access and 
Management System (ADAMS) Accession No. ML061650080), Virginia Electric 
and Power Company (Dominion) proposed exemptions from the requirements 
of 10 CFR Part 50, Appendix G and 10 CFR 50.61, to revise certain Surry 
1 and 2 reactor pressure vessel (RPV) initial (unirradiated) properties 
using Framatome Advanced Nuclear Power Topical Report (TR) BAW-2308, 
Revision 1, ``Initial RTNDT of Linde 80 Weld Materials.''
    The licensee requested an exemption from Appendix G to 10 CFR Part 
50 to replace the required use of the existing Charpy V-notch and drop 
weight-based methodology and allow the use of an alternate methodology 
to incorporate the use of fracture toughness test data for evaluating 
the integrity of the Surry 1 and 2 RPV circumferential beltline welds 
based on the use of the 1997 and 2002 editions of American Society for 
Testing and Materials (ASTM) Standard Test Method E 1921, ``Standard 
Test Method for Determination of Reference Temperature T0, 
for Ferritic Steels in the Transition Range,'' and American Society for 
Mechanical Engineering (ASME), Boiler and Pressure Vessel Code (Code), 
Code Case N-629, ``Use of Fracture Toughness Test Data to establish 
Reference Temperature for Pressure Retaining materials of Section III, 
Division 1, Class 1.'' The exemption is required since Appendix G to 10 
CFR Part 50, through reference to Appendix G to Section XI of the ASME 
Code pursuant to 10 CFR 50.55(a), requires the use of a methodology 
based on Charpy V-notch and drop weight data.
    The licensee also requested an exemption from 10 CFR 50.61 to use 
an alternate methodology to allow the use of fracture toughness test 
data for evaluating the integrity of the Surry 1 and 2 RPV 
circumferential beltline welds based on the use of the 1997 and 2002 
editions of ASTM E 1921 and ASME Code Case N-629. The exemption is 
required since the methodology for evaluating RPV material fracture 
toughness in 10 CFR 50.61 requires the use of the Charpy V-notch and 
drop weight data for establishing the PTS reference temperature 
(RTPTS).

3.0 Discussion

    Pursuant to 10 CFR 50.12(a), the Commission may, upon application 
by any interested person or upon its own initiative, grant exemptions 
from the requirements of 10 CFR Part 50 when (1) The exemptions are 
authorized by law, will not present an undue risk to public health or 
safety, and are consistent with the common defense and security; and 
(2) when special circumstances are present. These circumstances include 
the special circumstances that allow the licensee an exemption from the 
use of the Charpy V-notch and drop weight-based methodology required by 
10 CFR Part 50, Appendix G and 10 CFR 50.61. This exemption only 
modifies the methodology to be used by the licensee for demonstrating 
compliance with the requirements of 10 CFR Part 50, Appendix G and 10 
CFR 50.61, and does not exempt the licensee from meeting any other 
requirement of 10 CFR Part 50, Appendix G and 10 CFR 50.61.

Authorized by Law

    These exemptions would allow the licensee to use an alternate 
methodology to make use of fracture toughness test data for evaluating 
the integrity of the Surry 1 and 2 RPV circumferential beltline welds, 
and would not result in changes to operation of the plant. Section 
50.60(b) of 10 CFR Part 50 allows the use of alternatives to 10 CFR 
Part 50, Appendix G, or portions thereof, when an exemption is granted 
by the Commission under 10 CFR 50.12. In addition, Section 50.60(b) of 
10 CFR Part 50 permits different NRC-approved methods for use in 
determining the initial material properties. As stated above, 10 CFR 
50.12(a) allows the NRC to grant exemptions from the requirements of 10 
CFR Part 50, Appendix G and 10 CFR 50.61. The NRC staff has determined 
that granting of the licensee's proposed exemptions will not result in 
a violation of the Atomic Energy Act of 1954, as amended, or the 
Commission's regulations. Therefore, the exemptions are authorized by 
law.

No Undue Risk to Public Health and Safety

    The underlying purpose of Appendix G to 10 CFR Part 50 is to set 
forth fracture toughness requirements for ferritic materials of 
pressure-retaining components of the reactor coolant pressure boundary 
of light water nuclear power reactors to provide adequate margins of 
safety during any condition of normal operation, including anticipated 
operational occurrences and system hydrostatic tests, to which the 
pressure boundary may be subjected over its service lifetime. The 
methodology underlying the requirements of Appendix G to 10 CFR Part 50 
is based on the use of Charpy V-notch and drop weight data. The 
licensee proposes to replace the use of the existing Charpy V-notch and 
drop weight-based methodology by a fracture toughness-based methodology 
to demonstrate compliance with Appendix G to 10 CFR Part 50. The NRC 
staff has concluded that the exemptions are justified based on the 
licensee utilizing the fracture toughness methodology specified in BAW-
2308, Revision 1, within the conditions and limitations delineated in 
the NRC staff's safety evaluation (SE), dated August 4, 2005 (ADAMS 
Accession Number ML052070408). The use of the methodology specified in 
the NRC staff's SE will ensure that P-T limits developed for the Surry 
1 and 2 RPVs will continue to be based on an adequately conservative 
estimate of RPV material properties and ensure that the pressure-
retaining components of the reactor coolant pressure boundary retain 
adequate margins of safety during any condition of normal operation, 
including anticipated operational occurrences. This exemption only 
modifies the methodology to be used by the licensee for demonstrating 
compliance with the requirements of Appendix G to 10 CFR Part 50, and 
does not exempt the licensee from meeting any other requirement of 
Appendix G to 10 CFR Part 50.
    The underlying purpose of 10 CFR 50.61 is to establish requirements 
which ensure that a licensee's RPV will be protected from failure 
during a PTS event by evaluating the fracture toughness of RPV 
materials. The licensee seeks an exemption from 10 CFR 50.61 to use a 
methodology for the ``determination of adjusted/indexing reference 
temperatures.'' The licensee proposes to use ASME Code Case N-629 and 
the methodology outlined in its submittal, which are based on the use 
of fracture toughness data, as an alternative to the Charpy V-notch and 
drop weight-based methodology required by 10 CFR 50.61 for establishing 
the initial, unirradiated properties when calculating RTPTS 
values. The NRC staff has concluded that the exemption is justified 
based on the licensee utilizing the methodology specified in the NRC 
staff's SE regarding TR BAW-2308, Revision 1, dated August 4, 2005. 
This TR established an alternative method for determining initial 
(unirradiated) material reference temperatures for RPV welds 
manufactured using Linde 80 weld flux (i.e., ``Linde 80 welds'') and 
established weld wire heat-specific and Linde 80 weld generic values of 
this reference temperature. These weld wire heat-specific and Linde 80 
weld generic values may be used in lieu of the nil-ductility reference 
temperature (RTNDT)

[[Page 36514]]

parameter, the determination of which is specified by paragraph NB-2331 
of Section III of the ASME Code. Regulations associated with the 
determination of RPV material properties involving protection of the 
RPV from brittle failure or ductile rupture include Appendix G to 10 
CFR Part 50 and 10 CFR 50.61, the PTS rule. These regulations require 
that the initial (unirradiated) material reference temperature, 
RTNDT, be determined in accordance with the provisions of 
the ASME Code, and provide the process for determination of 
RTPTS, the reference temperature RTNDT, evaluated 
for the end of license fluence.
    In TR BAW-2308, Revision 1, the Babcock and Wilcox Owners Group 
(B&WOG) proposed to perform fracture toughness testing based on the 
application of the ``Master Curve'' evaluation procedure, which permits 
data obtained from sample sets tested at different temperatures to be 
combined, as the basis for redefining the initial (unirradiated) 
material properties of Linde 80 welds. NRC staff evaluated this 
methodology for determining Linde 80 weld initial (unirradiated) 
material properties and uncertainty in those properties, as well as the 
overall method for combining unirradiated material property 
measurements based on T0 values, property shifts from models 
in regulatory guide (RG) 1.99, Revision 2, which are based on Charpy V-
notch testing and a defined margin term to account for uncertainties in 
the NRC staff SE. Table 3 in the SE contains the NRC staff-accepted 
IRTTO and initial margin (denoted as [sigma]i) 
for specific Linde 80 weld wire heat numbers. In accordance with the 
conditions and limitations outlined in the NRC staff SE on TR BAW-2308, 
Revision 1, for utilizing the values in Table 3: the licensee has 
utilized the appropriate NRC staff-accepted IRTT0 and 
[sigma]i values for Linde 80 weld wire heat numbers; applied 
a chemistry factor of 167 [deg]F (the weld wire heat-specific chemical 
composition, via the methodology of RG 1.99, Revision 2, did not 
indicate that a higher chemistry factor should apply); applied a value 
of 28 [deg]F for [sigma][Delta] in the margin term; and submitted 
values for [Delta']RTNDT and the margin term for each Linde 
80 weld in the RPV through the end of the current operating license. 
Therefore, all conditions and limitations outlined in the NRC staff SE 
on TR BAW-2308, Revision 1, have been met for Surry 1 and 2.
    The use of the methodology in TR BAW-2308, Revision 1, will ensure 
the PTS evaluation developed for the Surry 1 and 2 RPVs will continue 
to be based on an adequately conservative estimate of RPV material 
properties and ensure the RPVs will be protected from failure during a 
PTS event. Also, when additional fracture toughness data relevant to 
the evaluation of the Surry 1 and 2 RPV circumferential welds is 
acquired as part of the surveillance program, this data must be 
incorporated into the evaluation of the Surry 1 and 2 RPV fracture 
toughness requirements.
    Based on the above, no new accident precursors are created by 
allowing an exemption to use an alternate methodology to comply with 
the requirements of 10 CFR 50.61 in determining adjusted/indexing 
reference temperatures; thus, the probability of postulated accidents 
is not increased. Also, based on the above, the consequences of 
postulated accidents are not increased. Therefore, there is no undue 
risk to public health and safety.
Consistent with Common Defense and Security
    The proposed exemption would allow the licensee to use an alternate 
methodology to allow the use of fracture toughness test data for 
evaluating the integrity of the Surry 1 and 2 RPV circumferential 
beltline welds. This change to Surry 1 and 2 has no relation to 
security issues. Therefore, the common defense and security is not 
impacted by these exemptions.

Special Circumstances

    Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii), 
are present whenever application of the regulation in the particular 
circumstances is not necessary to achieve the underlying purpose of the 
rule. The underlying purpose of 10 CFR part 50, Appendix G and 10 CFR 
50.61 is to protect the integrity of the reactor coolant pressure 
boundary by ensuring that each reactor vessel material has adequate 
fracture toughness. Therefore, since the underlying purpose of 10 CFR 
part 50, Appendix G and 10 CFR 50.61 is achieved by an alternative 
methodology for evaluating RPV material fracture toughness, the special 
circumstances required by 10 CFR 50(a)(2)(ii) for the granting of an 
exemption from portions of the requirements of 10 CFR Part 50, Appendix 
G and 10 CFR 50.61 exist.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the exemptions are authorized by law, will not present an 
undue risk to the public health and safety, and are consistent with the 
common defense and security. Also, special circumstances are present. 
Therefore, the Commission hereby grants the Virginia Electric and Power 
Company exemptions from the requirements of Appendix G to 10 CFR part 
50 and 10 CFR 50.61, to allow an alternative methodology that is based 
on using fracture toughness test data to determine initial, 
unirradiated properties for evaluating the integrity of the Surry 1 and 
2 RPV circumferential beltline welds with the following conditions:
    (1) The licensee must utilize the data and methodology specified in 
the NRC staff's safety evaluation (SE), dated August 4, 2005, which was 
based on: (a) Information submitted by the B&WOG in TR BAW-2308, 
Revision 1; (b) the August 19, 2003, response to an NRC staff Request 
for Additional Information (ADAMS Accession Number ML032380449); and 
(c) B&WOG letter dated March 25, 2005 (ADAMS Accession Number 
ML051320232);
    (2) When additional fracture toughness data relevant to the 
evaluation of the Surry 1 and 2 RPV circumferential welds is acquired 
as part of the ongoing plant RPV surveillance programs, the licensee 
must re-evaluate the fracture toughness of the units' RPV 
circumferential welds; and
    (3) The exemptions are granted for the licensee to utilize the most 
recent staff-approved version of BAW-2308 (currently BAW-2308, Revision 
1). Future revisions of BAW-2308 could affect fracture toughness data 
and analyses for Surry 1 and 2. Therefore, the licensee must review any 
future staff-approved revisions of BAW-2308 and update the units' 
fracture toughness assessments, based on the information in any staff-
approved revision of BAW-2308.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will not have a significant effect on the 
quality of the human environment (72 FR 35264).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 27th day of June 2007.

    For the Nuclear Regulatory Commission.
Catherine Haney,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. E7-12855 Filed 7-2-07; 8:45 am]
BILLING CODE 7590-01-P