Re: Debris removal and scanning

["Hampshire, John" <John.Hampshire@Jacobs.com>]

Surface release guidelines can be found in Reg Guide 1.86.  For natural
uranium (and its associated decay products), the relevant release
numbers are 1000 dpm/100 sq-cm removable alpha, 5000 dpm/100 sq-cm total
alpha (fixed plus removable) averaged over any 1 sq-meter, with no
single 100 sq-cm exceeding 15,000 dpm/100 sq-cm total alpha.  For
thorium the release levels are 200, 1000, and 3000 respectively.  For
radium-226, the limits are 20, 100, and 300 respectively; however, these
should only apply if your process concentrated radium-226 preferentially
over the concentration of uranium  (Ra-226 is included in the natural
uranium limits by reference to "associated decay products").

As an aside, these numbers also appear in 10 CFR 835, Appendix D, but
the radium-226 release limits for total contamination are higher (500
average and 1500 maximum total, but removable remains 20).