ALARA — A Concept Stretched too Far?

A 1983 Health Physics Journal editorial stated that the basic tenet of keeping “radiation exposures as low as practicable” is at least as old as the radiation protection programs borne from the Manhattan project. As this once philosophical goal has been increasingly codified into lengthy recipes for compliance by regulatory agencies much concern for added conservatism to radiation protection has been expressed (1, 2, 3, 4).

The U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE) profess to follow the International Commission on Radiation Protection (ICRP) and National Council on Radiation Protection and Measurements (NCRP) radiation dose guidance (5,6) as they prescribe standards and criteria to fit all sites.  However, it appears to this author that there is selective interpretation.  For example, radiation protection guidance for environmental remedial actions (i.e., interventions) at DOE legacy facilities is multi-layered and very conservative.  This layering begins with the use of the linear-non-threshold (LNT) model. The LNT lacks a conclusive scientific basis(7). And, Gunnar Walindar, a Swedish radiobiologist, calls the LNT one of the greatest scientific scandals of our time(8).  The model extrapolates from where statistically significant radiation risk has been shown(9), i.e., 100 millisievert (mSv; 10rem) two orders of magnitude less to the current International Commission on Radiation Protection (ICRP) standard, 1 mSv (100 mrem)(12), for the protection of the public.  U.S. regulatory agencies add another layer by reducing this standard by a factor of four to seven, in imposing soil cleanup dose standards of 15-25 mrem (5, 10).  Then we observe that dose models regularly use scenarios for the maximally exposed individual (MEI), typically a farmer or rancher whom moves onto contaminated or remediated areas, grows all the family food on the contaminated land, and seldom leaves home. Then after this detriment is calculated it is required that an “as low as reasonably achievable” (ALARA) assessment be performed to determine if the forecasted dose can be reduced even further.  This use of worst-case parameters, instead of “realistic” parameters as the DOE draft ALARA standard (6) suggests, adds even more layers of conservatism.  All this ratcheting down is done in spite of the LNT lacking a conclusively verified scientific basis (9,11).

The ICRP (12) framework for radiation protection make it clear in their first principles for those engaged in a practice, vis-a-vis  “people at work” that “No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to society to offset the radiation detriment it causes.”

The ICRP recommendations for intervention are somewhat different as illustrated by the following principles: (a) The proposed intervention should do more good than harm, i.e., the reduction in detriment resulting from the reduction in dose should be sufficient to justify the harm and the costs, including social costs, of the intervention. (b) The form, scale, and duration of the intervention should be optimized so that the net benefit of the reduction of dose, i.e., the benefit of the reduction in radiation detriment, less the detriment associated with the intervention, should be maximized. The Commission further states that, “In most situations, intervention cannot be applied at the source and has to be applied in the environment and to individuals freedom of action.   The dose limits recommended by the commission are intended for use in the control of practices.  The use of these dose limits, or of any other pre-determined dose limits, as the basis for deciding on intervention might involve measures that would be out of all proportion to the benefit obtained and would then conflict with the principle of justification.   The Commission therefore recommends against the application of dose limits for deciding the need for, or scope of, intervention.”

This author contends that the ICRP never intended to apply the principle of ALARA to remedial actions that fall in the intervention realm.  The application of the soil cleanup dose standard of 15 mrem aims to protect members of the public from an annual risk of nearly 1 in a million.  The additional layers make the protection even more. This combination requires more construction work and hence putting more risk on the worker (10-2 for an injury & 10-4 for a fatality) (13).

The application of ALARA adds unnecessary conservatism increasing risk for non-radiation caused injuries and fatalities.  This is certainly not what the ICRP scope intends, e.g., “The Commission therefore wishes to emphasize its view that ionizing radiation needs to be treated with care rather than fear and that its risks should be kept in perspective with other risks” (12).

This author strongly endorses the ICRP stance that each cleanup action should be evaluated on its own merits. What would be the basis of providing a guarantee of protection between sites, or cleaning up to background? To illustrate the problem one has only to compare the relative costs of cleaning up the Nevada Test Site (NTS).  For example, in DOE/NV-399 (14), it was estimated that ~500 acres were contaminated to a level  > 37.0 Becquerel/gram (Bq/g), 8,500 acres >3.7 Bq/g and 90,000 acres >0.37 Bq/g.  Cleanup experience at NTS indicated costs of 0.509 $ million/acre (15).  The Standard used was 7.4 Bq/g. If NV continues to use 7.4 Bq/g, for the 3,275 acres > this criteria, cost would be 1.67 $billion.  If a cleanup to background was the standard, the costs in Nevada alone would escalate from an estimated 46 $billion for the >0.37 Bq/g to near a $trillion for background.

The current system is not working as risks are out of balance and workers conducting environmental restoration are getting killed saving theoretical people and preventing hypothetical cancer(16).  One reason for this is that the interpretation of the promulgated guidelines developed for controlling prospective doses (i.e., the dose from practices and use of ALARA) has been mistakenly applied in situations requiring back fitting or intervention.

Bruce W. Church, Desert Research Institute

References:

  1. H. H. Rossi, “What Are the Limits of ALARA?  Health Physics, 39 (2); 1980.
  2. H. J. Dunster, “ALARA Or De Minimis?, Health Physics, 43 (3); 1982.
  3. J. A. Auxier, & H. W. Dickson, “Guest Editorial: Concern Over Recent  Use of the ALARA Philosophy,” Health Physics, 44 (6); 1983.
  4. G. J. Discus, “A Regulatory Perspective on Radiation Protection: Nuclear Law and Radiation Science – Does This Combination Work?  NRC Chairman’s speech at the International Nuclear Law Association Nuclear Inter Jura 1999.
  5. U. S. Department of Energy, “Applying the ALARA Process for Radiation Protection of the Public and Environmental Compliance with 10 CFR part 834 & DOE 5400.5 ALARA Program Requirements”, Vol. 1, DOE-STD-ALARA 1 draft, April 1997.
  6. United States General Accounting Office: Radiation Standards Scientific Basis Inconclusive, and EPA and NRC Disagreement Continues, GAO/RCED-00-152, June 2000.
  7. Gunnar Walinder, Has Radiation Protection Become a Health Hazard? Kärnkraftsäkerhert & Utbildning AB (The Swedish Nuclear Training & Safety Center), Nyköping.
  8. K.L. Mossman, E.G. de Planque, M. Goldman, K.E. Kase, S.M. Magnusson, L. M. Muntzing, and G.S. Roessler, “Bridging Radiation Policy and Science,” An International Conference, Warrenton, VA, December, 1999.
  9. Environmental Protection Agency: Office of Solid Waste and Emergency Response. “Establishment of Cleanup Levels for CERCLA Sites with Radioactive Contamination, OSWER No. 9200.4-18, 1997.
  10. P.S. Rohwer, Testimony before the House Science Subcommittee on Energy and      Environment, Hearing on “Reexamining the Scientific Basis for the Linear No-Threshold Model of Low-dose Radiation,” July 18, 2000.
  11. International Commission on Radiological Protection: Recommendations of the International Commission on Radiological Protection, ICRP Publication 60. Pergamon Press, Oxford, U.K., 1991.
  12. National Safety Council. (1998), “Accident Facts,” 1998 Edition, Itasca, IL
  13. US DOE/NV-399, “A Cost/Risk/Benefit Analysis of Alternative Cleanup Requirements for Plutonium Contaminated Soils On and Near the Nevada Test Site,” (May 1995). 
  14. S. Afong, A Cost of Cleaning Up Clean Slate I, “Personal Communication,” USDOE/NV (Jan., 1998).
  15. B.W. Church, “The Unacknowledged Transfer of Risk,” Environmental Science and Pollution Research, Special Issue 2, 2000.