United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

U.S. Nuclear Regulatory Commission

Question 40: Assume a licensee has defined its compliance

year as January 1, 1993 to December 31, 1993. What is the

mechanism to change its definition of year? For example,

the licensee wants to monitor from January 31, 1994 to

January 30, 1995, how should it account for the lost days

January 1 - 30, 1994? Is it acceptable to prorate the


Answer: No. The question refers to the definition of

"year" in 10 CFR 20.1003. The licensee is not allowed to

make the one-step change as postulated in the example in

the question because that change involves omitting certain

days. Omitting days, even with dose proration, is not

allowed. However, the license could accomplish the desired

change in two steps, one step in each of two consecutive

years, that would give a "year" beginning 1/31 of one

calendar year and ending 1/30 of the following year. The

first step, using the example, would be a change, at the

beginning of 1993, to a "year" of 1/1/93 to 1/30/94 (13

months). The second step would be a change, at the

beginning of 1994, to a "year" of 1/31/94 to 1/30/95. This

two-step change meets the requirement of "years" that begin

in January with no day omitted or duplicated in consecutive

years. (Reference: 10 CFR 20.1003)

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