[ RadSafe ] Dosimetry Survey

Sandy Perle sandyfl at cox.net
Thu Apr 12 17:54:48 CDT 2007


Let me first state that I don't have a clue as to whom your current
dosimetry provider (I don't know if it's GDS or a competitor) my comments
are based purely on regulatory and litigation principles.

Your stated proposal is quite reasonable. As you are already aware, from a
regulatory standpoint, the requirements for personal monitoring are specific
enough, and for those who are not familiar with US Regulations, I'll provide
the 10CFR20 requirements below. In my opinion, you are still being
conservative with some of the requirements you are proposing. On the other
hand, one needs to separate regulatory requirements from litigation
requirements (noting your previous litigation, dosimetry can be considered
cheap insurance, while it may not prevent a litigant from wining, or a
defendant from losing, it's more difficult to prove a non-dose without
dosimetry. You obviously have a lot of history to support your position:

§ 20.1502 Conditions requiring individual monitoring of external and
internal occupational dose.
Each licensee shall monitor exposures to radiation and radioactive material
at levels sufficient to demonstrate compliance with the occupational dose
limits of this part. As a minimum--

(a) Each licensee shall monitor occupational exposure to radiation from
licensed and unlicensed radiation sources under the control of the licensee
and shall supply and require the use of individual monitoring devices by--

(1) Adults likely to receive, in 1 year from sources external to the body, a
dose in excess of 10 percent of the limits in § 20.1201(a),

(2) Minors likely to receive, in 1 year, from radiation sources external to
the body, a deep dose equivalent in excess of 0.1 rem (1 mSv), a lens dose
equivalent in excess of 0.15 rem (1.5 mSv), or a shallow dose equivalent to
the skin or to the extremities in excess of 0.5 rem (5 mSv);

(3) Declared pregnant women likely to receive during the entire pregnancy,
from radiation sources external to the body, a deep dose equivalent in
excess of 0.1 rem (1 mSv);2 and

(4) Individuals entering a high or very high radiation area.

(b) Each licensee shall monitor (see § 20.1204) the occupational intake of
radioactive material by and assess the committed effective dose equivalent

(1) Adults likely to receive, in 1 year, an intake in excess of 10 percent
of the applicable ALI(s) in table 1, Columns 1 and 2, of appendix B to §§

(2) Minors likely to receive, in 1 year, a committed effective dose
equivalent in excess of 0.1 rem (1 mSv); and

(3) Declared pregnant women likely to receive, during the entire pregnancy,
a committed effective dose equivalent in excess of 0.1 rem (1 mSv).

[56 FR 23398, May 21, 1991, as amended at 60 FR 20185, Apr. 25, 1995; 63 FR
39482, July 23, 1998]

2 All of the occupational doses in § 20.1201 continue to be applicable to
the declared pregnant worker as long as the embryo/fetus dose limit is not

Even for members of the general public, the regulations are as follows:

§ 20.1301 Dose limits for individual members of the public.
(a) Each licensee shall conduct operations so that —

(1) The total effective dose equivalent to individual members of the public
from the licensed operation does not exceed 0.1 rem (1 mSv) in a year,
exclusive of the dose contributions from background radiation, from any
administration the individual has received, from exposure to individuals
administered radioactive material and released under § 35.75, from voluntary
participation in medical research programs, and from the licensee’s disposal
of radioactive material into sanitary sewerage in accordance with § 20.2003,

(2) The dose in any unrestricted area from external sources, exclusive of
the dose contributions from patients administered radioactive material and
released in accordance with § 35.75, does not exceed 0.002 rem (0.02
millisievert) in any one hour.

(b) If the licensee permits members of the public to have access to
controlled areas, the limits for members of the public continue to apply to
those individuals.

(c) Notwithstanding paragraph (a)(1) of this section, a licensee may permit
visitors to an individual who cannot be released, under § 35.75, to receive
a radiation dose greater than 0.1 rem (1 mSv) if—

(1) The radiation dose received does not exceed 0.5 rem (5 mSv); and

(2) The authorized user, as defined in 10 CFR Part 35, has determined before
the visit that it is appropriate.

(d) A licensee or license applicant may apply for prior NRC authorization to
operate up to an annual dose limit for an individual member of the public of
0.5 rem (5 mSv). The licensee or license applicant shall include the
following information in this application:

(1) Demonstration of the need for and the expected duration of operations in
excess of the limit in paragraph (a) of this section;

(2) The licensee's program to assess and control dose within the 0.5 rem (5
mSv) annual limit; and

(3) The procedures to be followed to maintain the dose as low as is
reasonably achievable.

(e) In addition to the requirements of this part, a licensee subject to the
provisions of EPA's generally applicable environmental radiation standards
in 40 CFR part 190 shall comply with those standards.

(f) The Commission may impose additional restrictions on radiation levels in
unrestricted areas and on the total quantity of radionuclides that a
licensee may release in effluents in order to restrict the collective dose.

[56 FR 23398, May 21, 1991, as amended at 60 FR 48625, Sept. 20, 1995; 62 FR
4133, Jan. 29, 1997; 67 FR 20370, Apr. 24, 2002; 67 FR 62872, Oct. 9, 2002]

In summary, your proposal for monitoring is still conservative and should be
acceptable to any regulator. Risk Managers and attorneys may be a different

Good luck!

Sandy Perle 
Senior Vice President, Technical Operations 
Global Dosimetry Solutions, Inc. 
2652 McGaw Avenue
Irvine, CA 92614

Tel: (949) 296-2306 / (888) 437-1714 Extension 2306 
Tel: (949) 419-1000 Extension 2306
Fax:(949) 296-1144

Global Dosimetry Website: http://www.dosimetry.com/ 
Personal Website: http://sandy-travels.com/ 

More information about the RadSafe mailing list