U.S. Nuclear Regulatory Commission
Question 451: May the codes "ND" (not detectable), "NR"
(not required), and "NC" (not calculated) be used more
generally in the radiation dose data blocks on the NRC
Forms 4 and 5 than is implied by the instructions on the
forms? The purpose in asking this question is to clarify
the guidance for filling out the forms provided in the
regulatory position and in the instructions on the reverse
side of the NRC Forms 4 and 5. The Form 5 instructions
appear to limit the use of the "NR" and "NC" codes to the
committed effective dose equivalent (CEDE) and the
committed dose equivalent (CDE), "ND" is not referenced in
the Form 5 instructions, and the NRC Form 4 instructions do
not appear to refer to any of these codes. We believe that
the references to the codes in the guidance and
instructions on the forms are as examples for emphasis, and
that the intent of the guidance is that "NR" and "ND" are
appropriate for use, as applicable, in any of the dose
blocks, and are not specifically limited for use by the
manner in which referenced or described in the guidance.
However, we do note that "NC" may only be applicable to the
CDE (e.g., if the CEDE were less than 1 rem).
Answer: Yes. As indicated in the second paragraph of
regulatory position 1.1 of the guide, "NR" should be
entered in the blocks on Forms 4 and 5 to indicate the
areas for which monitoring was not required and "ND" should
be entered on these forms to indicate "where monitoring was
provided but not measurable [detectable]". As indicated in
regulatory position 2.2 of the guide, the use of "NC" is
appropriate only for items 16 and 18 on NRC Forms 4 and 5
for cases in which the CEDE does not exceed 1 rem and there
are no overexposures in any dose category within the
monitoring year. (References: Regulatory Guide 8.7, Rev.
1; 10 CFR 20.2104, 10 CFR 20.2106).