[Federal Register Volume 75, Number 52 (Thursday, March 18, 2010)]
[Notices]
[Pages 13142-13144]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-5927]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-250 and 50-251; NRC-2010-0025]
Florida Power and Light Company; Turkey Point, Units 3 and 4;
Exemption
1.0 Background
Florida Power and Light Company (FPL, the licensee), is the holder
of Facility Operating License Nos. DPR-31 and DPR-41, which authorize
operation of the Turkey Point, Unit Nos. 3 and 4 (Turkey Point 3 and
4). The license provides, among other things, that the facility is
subject to all rules, regulations, and orders of the U.S. Nuclear
Regulatory Commission (NRC, the Commission) now or hereafter in effect.
The facility consists of two pressurized-water reactors located in
Florida City, Florida.
2.0 Request
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 10 CFR 50.61 provides fracture toughness requirements for
protection against pressurized thermal shock (PTS) events. By letter
dated March 18, 2009, (Agencywide Documents Access and Management
System (ADAMS) Accession No. ML090920408), FPL proposed exemptions from
the requirements of 10 CFR Part 50, Appendix G and 10 CFR 50.61, to
revise certain Turkey Point 3 and 4, reactor pressure vessel (RPV)
initial (unirradiated) properties using Framatome Advanced Nuclear
Power Topical Report (TR) BAW-2308, Revisions 1A and 2A, ``Initial
RTNDT of Linde 80 Weld Materials.'' This exemption addresses
only those parts of the regulations (i.e., 10 CFR 50.61 and 10 CFR Part
50, Appendix G) which discuss the definition or use of unirradiated
nil-ductility reference temperature, RTNDT(U), and its
associated uncertainty, [sigma][Delta]. All other
requirements of 10 CFR 50.61 and 10 CFR part 50, Appendix G are
unchanged by this exemption.
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 Turkey Point 3 and 4 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 Turkey Point 3 and 4 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).
On February 3, 2010, a new rule, 10 CFR 50.61a, ``Alternate
Fracture Toughness Requirements for Protection Against PTS Events,''
became effective. The NRC staff reviewed this new rule against Turkey
Point's exemption request and determined that there is no effect on the
exemption request. The new rule does not modify the requirements from
which the licensee has sought an exemption, and the alternative
provided by the new rule does not address the scope of issues
associated with both 10 CFR 50.61 and 10 CFR part 50, Appendix G that
the requested exemption does.
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. The licensee requested 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 Turkey Point 3 and 4 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
[[Page 13143]]
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, Revisions 1A and 2A, within the conditions and limitations
delineated in the NRC staff's safety evaluations (SEs), dated August 4,
2005 (ADAMS Accession Number ML052070408) and March 24, 2008
(ML080770349). The use of the methodology specified in the NRC staff's
SEs will ensure that pressure and temperature limits developed for the
Turkey Point 3 and 4 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
that ensure 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 SEs regarding TR BAW-2308, Revisions 1A and 2A, dated August 4,
2005, and March 24, 2008. 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) 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, IRTNDT, 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 To values (i.e., IRTTo),
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 IRTTo 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. Additionally,
the NRC's SE for TR BAW-2308, Revision 2 concludes that the revised
RTPTS values for Linde 80 weld materials are acceptable for
referencing in plant specific licensing applications as delineated in
TR BAW-2308, Revision 2 and to the extent specified under Section 4.0,
Limitations and Conditions, of the SE, which states: ``Future plant-
specific applications for RPVs containing weld heat 72105, and weld
heat 299L44, of Linde 80 welds must use the revised IRTTo
and [sigma]i, values in TR BAW-2308, Revision 2.''
Therefore, all conditions and limitations outlined in the NRC staff SEs
on TR BAW-2308, Revisions 1A and 2A, have been met for Turkey Point 3
and 4.
The use of the methodology in TR BAW-2308, Revisions 1A and 2A will
ensure the PTS evaluation developed for the Turkey Point 3 and 4 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.
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 Turkey Point 3 and 4 RPV
circumferential beltline welds. This change to Turkey Point 3 and 4 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.
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4.0 Conclusion
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), the exemptions are authorized by law, will not endanger life
or property or common defense and security, and is, otherwise, in the
public interest. Therefore, the Commission hereby grants the Florida
Power and Light Company exemptions from portions of 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 of fracture toughness test data to
determine initial, unirradiated properties for evaluating the integrity
of the Turkey Point RPV circumferential beltline welds. This exemption
addresses only those parts of the regulations (i.e., 10 CFR 50.61 and
10 CFR part 50, Appendix G) which discuss the definition or use of
unirradiated nil-ductility reference temperature, RTNDT(U),
and its associated uncertainty, [sigma][Delta]. All other
requirements of 10 CFR 50.61 and 10 CFR part 50, Appendix G are
unchanged by this exemption.
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 (75 FR 4426)
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 11th day of March 2010.
For the Nuclear Regulatory Commission.
Joseph G. Giitter,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. 2010-5927 Filed 3-17-10; 8:45 am]
BILLING CODE 7590-01-P