[Federal Register Volume 76, Number 71 (Wednesday, April 13, 2011)]
[Rules and Regulations]
[Pages 20489-20490]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-8836]



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  Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / 
Rules and Regulations  

[[Page 20489]]



DEPARTMENT OF ENERGY

10 CFR Part 835

[Docket No. HS-RM-09-835]
RIN 1992-AA-45


Occupational Radiation Protection

AGENCY: Office of Health, Safety and Security, Department of Energy.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The Department of Energy (DOE) today amends the values in 
appendix C to its Occupational Radiation Protection requirements. The 
derived air concentration values for air immersion are calculated using 
several parameters. One of these, exposure time, is better represented 
by the hours in the workday, rather than the hours in a calendar day, 
and is therefore used in the revised calculations.

DATES: This rule is effective May 13, 2011.

FOR FURTHER INFORMATION CONTACT: Dr. Judith Foulke, U.S. Department of 
Energy, Office of Worker Safety and Health Policy, 1000 Independence 
Avenue, SW., Washington, DC 20585; (301) 903-5865, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. Background

    The requirements in title 10, Code of Federal Regulations, part 835 
(10 CFR part 835), Occupational Radiation Protection, are designed to 
protect the health and safety of workers at Department of Energy (DOE) 
facilities. One situation that must be addressed is the exposure of 
workers to radioactive material dispersed in the air. Based on 
calculations involving doses to the organs of the body, levels of 
contamination in the air that will not cause the dose limits for 
workers to be exceeded are established for specified radionuclides. 
These values are given in appendix C. DOE first published a final rule 
on December 14, 1993, (58 FR 65485), amending 10 CFR part 835. In the 
June 8, 2007, (72 FR 31903) amendment to part 835, DOE revised the 
values in appendix C to part 835, Derived Air Concentration (DAC) for 
Workers from External Exposure during Immersion in a Cloud of Airborne 
Radioactive Material. The calculations done for the 2007 amendment were 
based on a 24-hour day. However, to be consistent with other 
occupational exposure scenarios, such as those used in developing the 
appendix A DACs, an 8-hour per day exposure scenario is more 
reasonable.
    DOE proposed amending the values in appendix C to take account of 
the 8-hour per day exposure scenario on January 25, 2011 (76 FR 4258). 
Today's final rule modifies 10 CFR part 835 appendix C values resulting 
from calculations using an 8-hour day.

II. Discussion of Changes to 10 CFR 835

    The values for air immersion derived air concentrations in the 
present part 835 are based on a 24-hour day. Because the work day is 8 
hours long, it was decided to base calculations of air immersion 
derived concentrations on an 8-hour day for workers occupationally 
exposed.
    DOE received two comments from one commenter. The commenter stated 
that the derived conversion factors differed by a factor of 20 billion 
to 70 billion. DOE noted that values calculated in Bq/m\3\ and in 
[mu]Ci/L differ by a factor of 37 billion, but use of truncated numbers 
explained the difference. The commenter stated that the half-life of 
Kr-77 was wrong. DOE agreed with the correct value and replaced the 
incorrect value.
    A second commenter stated that the change in calculation for 
exposure time from calendar day hours to workday hours will lessen the 
amount of protection provided to employees. The commenter incorrectly 
stated that the effects of the radiation will continue after the 
employees have gone home. These radionuclides in appendix C are inert 
gases and are not absorbed by the body; they affect the worker only 
while immersed in a cloud of airborne radioactivity.
    A third commenter agreed with DOE's approach.

III. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects in 10 CFR Part 835

    Federal buildings and facilities, Nuclear energy, Nuclear 
materials, Nuclear power plants and reactors, Nuclear safety, 
Occupational safety and health, Radiation protection, and Reporting and 
recordkeeping requirements.

    Issued in Washington, DC, on March 28, 2011.
Glenn S. Podonsky,
Chief Health, Safety and Security Officer, Office of Health, Safety and 
Security.

    Accordingly, for the reasons set forth in the preamble, part 835 of 
Chapter III of Title 10 of the Code of Federal Regulations is amended 
as set forth below:

PART 835--OCCUPATIONAL RADIATION PROTECTION

0
1. The authority citation for part 835 continues to read as follows:

    Authority: 42 U.S.C. 2201, 7191; 50 U.S.C. 2410.


0
2. In appendix C to part 835, the table at the end of paragraph c. is 
removed and a new table is added to read as follows:

Appendix C to Part 835--Derived Air Concentration (DAC) for Workers 
From External Exposure During Immersion in a Cloud of Airborne 
Radioactive Material

* * * * *
    c. * * *

                            Air Immersion DAC
------------------------------------------------------------------------
                                                  ([micro]Ci/
         Radionuclide              Half-life         mL)       (Bq/m\3\)
------------------------------------------------------------------------
Ar-37........................  35.02 d.........  3E+00        1E+11
Ar-39........................  269 yr..........  1E-03        5E+07
Ar-41........................  1.827 h.........  3E-06        1E+05
Kr-74........................  11.5 min........  3E-06        1E+05
Kr-76........................  14.8 h..........  1E-05        3E+05
Kr-77........................  74.7 min........  4E-06        1E+05
Kr-79........................  35.04 h.........  1E-05        6E+05
Kr-81........................  2.1E+05 yr......  7E-04        2E+07
Kr-83m.......................  1.83 h..........  7E-02        2E+09
Kr-85........................  10.72 yr........  7E-04        2E+07
Kr-85m.......................  4.48 h..........  2E-05        1E+06
Kr-87........................  76.3 min........  4E-06        1E+05
Kr-88........................  2.84 h..........  1E-06        7E+04

[[Page 20490]]

 
Xe-120.......................  40.0 min........  1E-05        4E+05
Xe-121.......................  40.1 min........  2E-06        8E+04
Xe-122.......................  20.1 h..........  8E-05        3E+06
Xe-123.......................  2.14 h..........  6E-06        2E+05
Xe-125.......................  16.8 h..........  1E-05        6E+05
Xe-127.......................  36.406 d........  1E-05        6E+05
Xe-129m......................  8.89 d..........  2E-04        7E+06
Xe-131m......................  11.84 d.........  5E-04        1E+07
Xe-133.......................  5.245 d.........  1E-04        5E+06
Xe-133m......................  2.19 d..........  1E-04        5E+06
Xe-135.......................  9.11 h..........  1E-05        6E+05
Xe-135m......................  15.36 min.......  1E-05        3E+05
Xe-138.......................  14.13 min.......  3E-06        1E+05
------------------------------------------------------------------------

* * * * *

[FR Doc. 2011-8836 Filed 4-12-11; 8:45 am]
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