Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20555
July 3, 1986
TO: ALL NON-POWER REACTOR LICENSEES AUTHORIZED TO USE HEU FUEL
SUBJECT: CRITERIA FOR UNIQUE PURPOSE EXEMPTION FROM CONVERSION FROM
THE USE OF HEU FUEL (GENERIC LETTER 86-12)
10 CFR 50.64 (51 FR 6514) provides for a "unique purpose" exemption from the
requirement to convert from the use of high enriched uranium (HEU) fuel,
provided the licensee presents a justification that is accepted by the
Commission. Amended 10 CFR 50.2 gives broad definitions for acceptable
unique purposes. This letter provides more specific guidance for those
licensees who believe they might qualify for such an exemption.
The definition states that a unique purpose means a project, program, or
commercial activity that cannot be reasonably accomplished without the use
of HEU fuel, and may include one or more of the following four purposes:
1) A specific experiment, program, or commercial activity (typically
long-term) that significantly serves the U.S. national interest and
cannot be accomplished without the use of HEU fuel;
2) Reactor physics or reactor development based explicitly on the use of
HEU fuels;
3) Research projects based on neutron flux levels or spectra attainable
only with HEU fuel; or
4) A reactor core of special design that could not perform its intended
function without using HEU fuel.
The definition provides guidance to licensees who believe they might qualify
for a unique purpose exemption to develop a basis for exemption that best
fits each unique situation, and which would provide a justification that the
Commission could find acceptable. These four purposes are not necessarily
the only ones that might form the basis for a unique purpose exemption.
However, the following discussion relates to the four given in the 10 CFR
50.2 definition.
Purpose number 1 is intended to relate primarily to technical activities
closely coupled to the national interest, which might include preeminence in
a specific field of research or assurance of a domestic supply of some
essential product of reactor operation. This was included in the definition
of "unique purpose" to help provide the Nuclear Regulatory Commission (NRC)
wide latitude of discretion like the standards in 10 CFR 50.41.
8607030269
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Of the four purposes identified, it is intended that numbers (2) and (4)
provide opportunity to perform new reactor projects whose objectives were to
learn about or develop reactor concepts for which parameters of HEU were a
necessary component. Examples might be a unique compact reactor heat source,
a compact pulsing reactor with minimal distortion of fast neutron spectra,
or a comparison of HEU and low enriched uranium (LEU) operating cores for
assessing the potential for conversions of non-power reactor cores.
Purpose number 3 is intended to provide the opportunity to continue using
HEU fuel if converting to available LEU fuel would change neutron flux
densities or spectra, or other essential radiation parameters, so that the
fundamental reason for conducting the reactor-based program would be lost,
or irreparably compromised.
Purpose number 4 might also pertain to a non-power reactor that was designed
and is operated to take maximum advantage of the unique characteristics of
HEU fuel and where the substitution of any available LEU fuel could not be
made without major facility modification to accommodate such things as a
larger core, different coolant systems, or major changes in its primary mode
of operation. An example would be a core with specific physical size limits
that currently uses near-maximum uranium density in its fuel.
An application for exemption from conversion from HEU fuel must be submitted
to the Director, Office of Nuclear Reactor Regulation, in accordance with
the schedule given in the published regulation. The application should
specify the date when acceptable LEU or medium enriched uranium (MEU) fuel
is expected to be available, and a conversion schedule provided where
appropriate. The NRC expects that only very few licensees will qualify for
exemption. The following are examples of items which should be considered
and developed in detail, as appropriate, in any application for exemption:
(1) Identification and outline of the program
(2) Explanation of the value of the program and any special
experiments to the U.S. national interests
(3) Discussion of how the achievement of significant and competitive
results is dependent on such factors as the following:
(a) neutron fluence (e.g., power level and operating schedule)
(b) neutron flux density e.g., power level, core size)
(c) neutron spectra
(d) signal-to-noise ratio in the experimental results
(e) operating and refueling schedule for the reactor
(f) operating costs
(g) waste management
(4) Discussion of program accomplishment with available LEU fuels, and
specification of LEU fuel characteristics required to permit
continuation of the programs with no significant decrement in
accomplishment.
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This letter is for guidance only in interpreting 10 CFR 50.64. No response
or action is necessary other than that required by the regulation to apply
for a unique purpose exemption.
Questions should be addressed to Mr. Robert E. Carter at (301) 492-8206.
Frank J. Miraglia, Director
Division of PWR Licensing-B
