[Federal Register Volume 68, Number 235 (Monday, December 8, 2003)]
[Notices]
[Pages 68428-68430]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-30360]


-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-286]


Entergy Nuclear Operations, Inc., Indian Point Nuclear Generating 
Unit No. 3; Exemption

1.0 Background

    Entergy Nuclear Operations, Inc. (Entergy, the licensee) is the 
holder of Facility Operating License No. DPR-64 which authorizes 
operation of the Indian Point Nuclear Generating Unit No. 3 (IP3). 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 a pressurized-water reactor located in 
Westchester County in the State of New York.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), part 50, 
requires that reactor coolant system (RCS)

[[Page 68429]]

pressure-temperature (P-T) limits be established for reactor pressure 
vessels (RPVs) during normal operating and hydrostatic or leak rate 
testing conditions. Specifically, Appendix G to 10 CFR part 50 states 
that ``[t]he appropriate requirements on both the pressure-temperature 
limits and the minimum permissible temperature must be met for all 
conditions.'' Furthermore, Appendix G to 10 CFR part 50 specifies that 
the requirements for these limits are based on the application of 
evaluation procedures given in Appendix G to Section XI of the American 
Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME 
Code). Appendix G to 10 CFR part 50 also specifies that the Editions 
and Addenda of the ASME Code which are incorporated by reference in 10 
CFR 50.55a apply to the requirements in Appendix G to 10 CFR part 50. 
In the 2003 Edition of 10 CFR, the NRC endorsed Editions and Addenda of 
the ASME Code through the 1998 Edition and 2000 Addenda. However, 
Entergy has currently incorporated the 1989 Edition of the ASME Code 
into the IP3 licensing basis for defining the ASME Code requirements 
which apply to the facility's ASME Code, Section XI program. Hence, 
with respect to the statements from Appendix G to 10 CFR part 50 
referenced above, it is the 1989 Edition of Appendix G to Section XI of 
the ASME Code which continues to apply to IP3. Finally, 10 CFR 50.60(b) 
states that, ``[p]roposed alternatives to the described requirements in 
[Appendix G] of this part or portions thereof may be used when an 
exemption is granted by the Commission under [10 CFR 50.12].''
    Entergy has requested, in a separate submittal dated May 28, 2003, 
an amendment to the IP3 Technical Specification (TS) P-T limit curves. 
In order to address the provisions of this amendment, Entergy has also 
requested that the staff exempt IP3 from the application of specific 
requirements of Appendix G to 10 CFR part 50, and substitute the use of 
ASME Code Case N-640. ASME Code Case N-640 permits the use of an 
alternate reference fracture toughness curve for RPV materials when 
determining P-T limits. The proposed exemption request is consistent 
with, and is needed to support, the proposed IP3 TS amendment that was 
provided in the separate submittal. The proposed IP3 TS amendment will 
revise the P-T limits for heatup, cooldown, and inservice test 
limitations for the reactor coolant system (RCS) through 20 effective 
full-power years of operation.

Code Case N-640

    The requested exemption would allow use of ASME Code Case N-640 in 
conjunction with Appendix G to Section XI of the ASME Code, 10 CFR 
50.60(a), and Appendix G to 10 CFR part 50 to establish P-T limits for 
the IP3 RPV.
    The licensee's proposed TS amendment to revise the P-T limits for 
IP3 relies, in part, on the requested exemption. These revised P-T 
limits have been developed using the lower bound KIC 
fracture toughness curve given in Appendix A to Section XI of the ASME 
Code, Figure A-2200-1, in lieu of the lower bound KIA 
fracture toughness curve given in Appendix G to Section XI of the ASME 
Code, Figure G-2210-1, as the basis fracture toughness curve for 
defining the IP3 P-T limits. All other margins involved with the ASME 
Code, Section XI, Appendix G process of determining P-T limit curves 
remain unchanged.
    Use of the KIC curve as the basis fracture toughness 
curve for the development of P-T operating limits is technically 
correct. The KIC curve appropriately implements the use of a 
relationship based on static initiation fracture toughness behavior to 
evaluate the controlled heatup and cooldown process of an RPV, whereas 
the KIA fracture toughness curve, as given in Appendix G to 
Section XI of the ASME Code, was developed from more conservative crack 
arrest and dynamic fracture toughness test data. The application of the 
KIA fracture toughness curve was initially codified in 
Appendix G to Section XI of the ASME Code in 1974 to provide a 
conservative representation of RPV material fracture toughness. This 
initial conservatism was necessary due to the limited knowledge of RPV 
material behavior in 1974. Since that time, however, additional 
knowledge about RPV materials has been gained, which demonstrates that 
the lower bound on fracture toughness, provided by the KIA 
fracture toughness curve, is well beyond the margin of safety required 
to protect the public health and safety from potential RPV failure.
    In addition, P-T limit curves based on the KIC fracture 
toughness curve will enhance overall plant safety by opening the P-T 
operating window with the greatest safety benefit in the region of low 
temperature operations. The operating window through which the operator 
heats up and cools down the RCS is determined by the difference between 
the maximum allowable pressure, determined by Appendix G to Section XI 
of the ASME Code, and the minimum required pressure for the reactor 
coolant pump (RCP) seals adjusted for instrument uncertainties. A 
narrow operating window could potentially have an adverse safety impact 
by increasing the possibility of inadvertent overpressure protection 
system (OPPS) actuation due to pressure surges associated with normal 
plant evolutions such as RCS pump starts and swapping operating 
charging pumps with the RCS in a water-solid condition.
    Since application of ASME Code Case N-640 provides appropriate 
procedures to establish maximum postulated defects and to evaluate 
those defects in the context of establishing RPV P-T limits, this 
application of the Code Case maintains an adequate margin of safety for 
protecting RPV materials from brittle failure. Therefore, the licensee 
concluded that these considerations were special circumstances pursuant 
to 10 CFR 50.12(a)(2)(ii), ``[a]pplication of the regulation in the 
particular circumstances would not serve the underlying purpose of the 
rule or is not necessary to achieve the underlying purpose of the 
rule.''
    In summary, the ASME Code, Section XI, Appendix G procedure was 
conservatively developed based on the level of knowledge existing in 
1974 concerning reactor coolant pressure boundary materials and the 
estimated effects of operation. Since 1974, the level of knowledge 
about the fracture mechanics behavior of RCS materials has been greatly 
expanded, especially in regard to the effects of radiation 
embrittlement and the understanding of fracture toughness properties 
under static and dynamic loading conditions.

3.0 Discussion

    Pursuant to 10 CFR 50.12, 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 the public health 
and safety, and are consistent with the common defense and security; 
and (2) when special circumstances are present.
    Special circumstances, pursuant to 10 CFR 50.12(a)(2)(ii), are 
present because the continued operation of IP3 with the P-T curves 
developed in accordance with Appendix G to Section XI of the ASME Code, 
without the relief provided by ASME Code Case N-640, is not necessary 
to achieve the underlying purpose of Appendix G to 10 CFR part 50. 
Application of ASME Code Case N-640 in lieu of the requirements of 
Appendix G to Section XI of the ASME Code provides an acceptable 
alternative evaluation procedure, which will

[[Page 68430]]

continue to meet the underlying purpose of Appendix G to 10 CFR part 
50. The underlying purpose of the regulations in Appendix G to 10 CFR 
part 50 is to provide an acceptable margin of safety against brittle 
failure of the RCS during any condition of normal operation to which 
the pressure boundary may be subjected over its service lifetime.
    The NRC staff examined the licensee's rationale to support the 
exemption request, and accepts the licensee's determination that an 
exemption would be required to approve the use of ASME Code Case N-640. 
The staff has also concluded that the use of ASME Code Case N-640 would 
meet the underlying intent of Appendix G to 10 CFR part 50. The NRC 
staff concluded that the application of the technical provisions of 
ASME Code Case N-640 provided sufficient margin in the development of 
RPV P-T limit curves such that the underlying purpose of the 
regulations contained in Appendix G to 10 CFR part 50 continued to be 
met. Therefore, the specific conditions required by the regulations; 
i.e., the use of all provisions in Appendix G to Section XI of the ASME 
Code, were not necessary. The NRC staff has, therefore, concluded that 
the exemption requested by Entergy is justified based on the special 
circumstances of 10 CFR 50.12(a)(2)(ii), ``[a]pplication of the 
regulation in the particular circumstances would not serve the 
underlying purpose of the rule or is not necessary to achieve the 
underlying purpose of the rule.''
    Based upon a consideration of the conservatism that is explicitly 
incorporated into the methodologies of Appendix G to 10 CFR part 50 and 
Appendix G to Section XI of the ASME Code, the staff concluded that the 
application of ASME Code Case N-640 would provide an adequate margin of 
safety against brittle failure of the RPV. This is also consistent with 
the determination that the staff has reached for other licensees under 
similar conditions based on the same considerations. The staff 
concludes that the exemption requested by Entergy is appropriate under 
the special circumstances of 10 CFR 50.12(a)(2)(ii), and the 
methodology of ASME Code Case N-640 may be used to revise the P-T 
limits for the IP3 RPV. Pursuant to 10 CFR 50.12(a)(1), the granting of 
this exemption is authorized by law, will not present undue risk to the 
public health and safety, and is consistent with the common defense and 
security. Therefore, the staff considers granting an exemption to 10 
CFR 50.60(a) and Appendix G to 10 CFR part 50 to allow use of ASME Code 
Case N-640 as part of the basis for generating the P-T limit curves for 
IP3 is appropriate.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the exemption is authorized by law, will not present an undue 
risk to the public health and safety, and is consistent with the common 
defense and security. Also, special circumstances are present. 
Therefore, the Commission hereby grants Entergy an exemption from the 
requirements of 10 CFR 50.60 and Appendix G to 10 CFR part 50, to allow 
for the application of ASME Code Case N-640 in establishing TS 
requirements for the RPV P-T limits for IP3.
    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 (68 FR 67490).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 2nd day of December, 2003.

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh, Director,
Division of Licensing Project Management, Office of Nuclear Reactor 
Regulation.
[FR Doc. 03-30360 Filed 12-5-03; 8:45 am]
BILLING CODE 7590-01-P