69052 Federal Register / Vol. 65, No. 221 / Wednesday, November 15, 2000 / Notices

The meeting is open to the public.

Dated: November 8, 2000.

Mary Ann Hadyka,

Committee Management Officer.

[FR Doc. 00–29106 Filed 11–14–00; 8:45 am]

BILLING CODE 7515–01–U

NATIONAL SCIENCE FOUNDATION

Notice of Meeting; Seminar: Research

to Develop an Artificial Retina

November 22, 2000.

Name: Seminar: ‘‘RESEARCH TO

DEVELOP AN ARTIFICIAL RETINA’’.

Date and Time: November 22, 2000;

8:30 am–12 noon.

Place: National Science Foundation,

4201 Wilson Boulevard, Room 110,

Arlington, VA 22230.

Type of Meeting: Open.

Contact Person: Gilbert Devey,

Program Director, biomedical

Engineering and Research to Aid

Persons with Disabilities, Division of

Bioengineering and Environmental

Systems, National Science Foundation,

4201 Wilson Boulevard, Arlington, VA

2223, Telephone: (703) 292–8320.

Purpose of Meeting: The broad

purpose of the meeting is to brief NSF

management and program officers on

federal agency research project support,

other worldwide R&D directed to the

development of a chronic retinal

prosthesis, and to indicate the context

in which NSF provides support for the

research.

AGENDA

8:30 a.m.—Registration

9:00 a.m.—Welcome

9:15 a.m.—Presentation

10:15 a.m.—Break

10:30 a.m.—Discussion

11:30 a.m.—Open Discussion

11:45 a.m.—Wrap-Up

Dated: November 8, 2000.

Karen J. York,

Committee Management Officer.

[FR Doc. 00–29170 Filed 11–14–00; 8:45 am]

BILLING CODE 7555–01–M

NUCLEAR REGULATORY

COMMISSION

[Docket Nos. 50–373, 50–374]

In the Matter of Commonwealth Edison

Company (LaSalle County Station,

Units 1 and 2); Exemption

I.

Commonwealth Edison Company

(ComEd, the licensee) is the holder of

Facility Operating Licenses Nos. NPF–

11 and NPF–18 for operation of LaSalle

County Station, Units 1 and 2, located

in LaSalle County, Illinois. The licenses

state, among other things, that the

facility is subject to all of the rules,

regulations, and orders of the U.S.

Nuclear Regulatory Commission (the

Commission) now or hereafter in effect.

II.

Title 10 of the Code of Federal

Regulations (10 CFR) Part 50, Appendix

G, requires that pressure-temperature

(P–T) limits be established for reactor

pressure vessels (RPVs) during normal

operating and hydrostatic or leak rate

testing conditions. Specifically, 10 CFR

Part 50, Appendix G states, ‘‘The

appropriate requirements on both the

pressure-temperature limits and the

minimum permissible temperature must

be met for all conditions.’’ Appendix G

of 10 CFR Part 50 specifies that the P–

T limits must meet the safety margin

requirements specified in the American

Society of Mechanical Engineers

(ASME) Boiler and Pressure Vessel Code

(Code), Section XI, Appendix G. ASME

Code specifies use of K1A fracture

toughness curve.

To address provisions of the proposed

amendments to the technical

specification (TS) P–T limits, in its

submittal of February 29, 2000, the

licensee requested that the staff exempt

LaSalle from application of specific

requirements of 10 CFR 50.60(a) and

Appendix G, and substitute use of

ASME Code Case N–640.

Code Case N–640 permits the use of

an alternate reference fracture toughness

(K1c fracture toughness curve instead of

K1a fracture toughness curve) for reactor

vessel materials in determining the P–T

limits. Since the K1c fracture toughness

curve shown in ASME Code, Section XI,

Appendix A, Figure A–2200–1 provides

greater allowable fracture toughness

than the corresponding K1a fracture

toughness curve of ASME Code, Section

XI, Appendix G, Figure G–2210–1 (the

K1a fracture toughness curve), using

Code Case N–640 for establishing the P–

T limits would be less conservative than

the methodology currently endorsed by

10 CFR Part 50, Appendix G and,

therefore, an exemption to apply the

Code Case would be required.

Code Case N–640 (formerly Code Case

N–626)

The licensee has proposed an

exemption to allow the use of ASME

Code Case N–640 in conjunction with

ASME Code, Section XI; 10 CFR

50.60(a); and 10 CFR Part 50, Appendix

G, to determine P–T limits.

The proposed amendments to revise

the P–T limits for LaSalle rely in part on

the requested exemption. These revised

P–T limits have been developed using

the K1c fracture toughness curve, in lieu

of the K1a fracture toughness curve, as

the lower bound for fracture toughness.

Use of the K1c curve in determining

the lower bound fracture toughness in

the development of P–T operating limits

curve is more technically correct than

use of the K1a curve since the rate of

loading during a heatup or cooldown is

slow and is more representative of a

static condition than a dynamic

condition. The K1c curve appropriately

implements the use of static initiation

fracture toughness behavior to evaluate

the controlled heatup and cooldown

process of a reactor vessel. The staff has

required use of the initial conservatism

of the K1a curve since 1974 when the

curve was codified. This initial

conservatism was necessary due to the

limited knowledge of RPV materials.

Since 1974, additional knowledge has

been gained about RPV materials, which

demonstrates that the lower bound on

fracture toughness provided by the K1a

curve is well beyond the margin of

safety required to protect the public

health and safety from potential RPV

failure. In addition, P–T curves based on

the K1c curve would enhance overall

plant safety by opening the P–T

operating window with the greatest

safety benefit in the region of low

temperature operations.

Since the reactor coolant system

(RCS) P–T operating window is defined

by the P–T operating and test limit

curves developed in accordance with

the ASME Code, Section XI, Appendix

G, continued operation of LaSalle with

these P–T curves without the relief

provided by ASME Code Case N–640

would unnecessarily require that the

RPV maintain a temperature exceeding

212 degrees Fahrenheit in a limited

operating window during pressure tests.

Consequently, steam vapor hazards

would continue to be one of the safety

concerns for personnel conducting

inspections in primary containment.

Implementation of the proposed P–T

curves, as allowed by ASME Code Case

N–640, does not significantly reduce the

margin of safety and would eliminate

steam vapor hazards by allowing

inspections in primary containment to

be conducted at lower coolant

temperature. Thus, pursuant to 10 CFR

50.12(a)(2)(ii), the underlying purpose

of the regulation will continue to be

served.

In summary, the ASME Code, Section

XI, Appendix G, procedure was

conservatively developed based on the

level of knowledge existing in 1974

concerning RPV materials and the

estimated effects of operation. Since