Answer to Question #558 Submitted to "Ask the Experts"

Q

There appear to be several errors in Column 4 of Table B.4 of ANSI N13.12-1999. The Bq/cm2 equivalents of the Reg. Guide 1.86 limits are provided in this column. I believe that the Bq/cm2 value should be 0.0166 for the following isotopes, ¹²⁵I, ¹²⁹I, ²²⁶Ra, ²²⁸Ra, ²²⁸Th, ²³⁰Th, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Am, and ²⁴⁴Cm. Please confirm if this is correct and if so, has a revision to ANSI/HPS N13.12-1999 been issued?

A

The writing group was made aware of problems with Table B.4 during the summer of 1999. The Bq/cm² equivalents for the radionuclides described in the question should be 0.0166, not 0.166 as shown in the table. In addition, the values for ¹³¹I and ²⁴¹Pu should also be 0.0166, and the value for ⁹⁰Sr should be 0.166 instead of 0.83. Finally, the headings for Columns 2 and 3 of the second page of Table B.4 should indicate a dose of 10 µSv/y (instead of 1 µSv/y). Since both Annex A and Annex B of HPS/ANSI N13.12 are informative (for information only), not normative (mandatory), there are no current plans to issue a revision to the standard. HPS/ANSI standards are typically under a five-year evaluation cycle to determine if revisions are necessary. The full standard will be reviewed in 2004 to determine if a full revision is necessary.



William E. Kennedy, Jr.,

Chairperson ANSI/HPS N13.12-1999 Working Group