11 April th International High-Energy Physics Technical Safety Forum 1 Radiation Protection and Safety in High-Energy Physics Kenneth R. Kase, Ph.D. Associate Director, Environment, Safety and Health (Retired) Stanford Linear Accelerator Center & Senior Vice President National Council on Radiation Protection and Measurements

11 April th International High-Energy Physics Technical Safety Forum 2 Outline Brief Overview of Radiation Protection Standards Relationship of Radiation Safety to Other Safety Concerns Current and Future Issues in Radiation Protection Related to High-Energy Physics

11 April th International High-Energy Physics Technical Safety Forum Erythema Limit Mutscheller: 1/100 erythema dose in 30 days Sievert: 1/10 erythema dose in 1 year Threshold concept

11 April th International High-Energy Physics Technical Safety Forum 4 ICRU Formed by the International Congress of Radiology (ICR) X-Ray Units Committee Physical measurement required

11 April th International High-Energy Physics Technical Safety Forum “Roentgen” Defined “Roentgen”: Proposed by the “Units” Committee in 1925 Adopted by the ICR in 1928 “the exposure when the x-ray or gamma-ray field produces 1 e.s.u. of negative charge in gram of air” ICRP and NCRP were formed

11 April th International High-Energy Physics Technical Safety Forum Dose Limits Established ICRP0.2 R/day NCRP0.1 R/day

11 April th International High-Energy Physics Technical Safety Forum New Information Excessive radium use by the public via patent medicines Radium dial painters exhibit damage 0.1  g Radium Body Burden accepted

11 April th International High-Energy Physics Technical Safety Forum –1954 ICRP and NCRP New Set of Weekly Dose Limits  300 mR — blood forming organs lens, gonads  600 mR — skin  300 – 600 mR — other organs  1,500 mR — extremities (x rays)  1/10 these values for minors

11 April th International High-Energy Physics Technical Safety Forum 9 Public Concern BEAR Committee (US National Academy of Sciences) MRC Committee (UK Medical Radiation Council) UNSCEAR (United Nations)

11 April th International High-Energy Physics Technical Safety Forum –1958 ICRP and NCRP New Age-Related Worker Limits  5 x (age – 18) rem/year,  3 rem/13 weeks (head, trunk, active blood forming organs, lens, and gonads)

11 April th International High-Energy Physics Technical Safety Forum –1958 ICRP and NCRP New Population Limit  5 rem/30 years(170 mrem/year)  Small groups — 0.5 rem/year

11 April th International High-Energy Physics Technical Safety Forum ICRP Examine need for new limits  Greatly expanded use  New risk estimates  Risk-Based Approach

11 April th International High-Energy Physics Technical Safety Forum ICRP Risk Estimates  D +  D 2, i.e., linear at low doses Fatal cancer risk coefficient 1 x per Sv (1 x per rem) Hereditary risk 0.4 x per Sv (0.4 x per rem) [Note: 1 Sv = 100 rem]

11 April th International High-Energy Physics Technical Safety Forum 14 Approach to Worker Limit (Stochastic) Is 50 mSv/year acceptable? Fatal accident rate in safe industries was 1 x /year Average dose to workers will be <10 mSv/year (risk of /year) 50 mSv/year limit provides same level of risk as safe industries

11 April th International High-Energy Physics Technical Safety Forum –1993 ICRP and NCRP New Dose Limits for Workers  ICRP  50 mSv/year maximum  100 mSv/5 year (20 mSv/year)  NCRP  50 mSv/year maximum  Age in 10’s of mSv

11 April th International High-Energy Physics Technical Safety Forum 16 Maximum Radiation Risks at HEP Facilities Annual exposures to almost all workers are less than 5 mSv This results in an annual added risk for a fatal cancer less than 3x10 -4 And an added lifetime cancer risk of 1% or less

11 April th International High-Energy Physics Technical Safety Forum 17 Relationship of Radiation Safety to Other Safety Concerns Is it just another occupational hazard like electricity, construction, high pressure, vacuum, toxic chemicals and gases ? Does it need to be treated differently?

11 April th International High-Energy Physics Technical Safety Forum 18 Relationship of Radiation Safety to Other Safety Concerns Engineering and design  Shielding  Access control Compare with electrical

11 April th International High-Energy Physics Technical Safety Forum 19 Current and Future Issues in Radiation Protection Radiation is a hazard that presents risks similar to other industrial hazards at high energy physics facilities It need not be treated differently from other hazards. But, perhaps some of the principles used for radiation protection could be applied to the mitigation of other hazards

11 April th International High-Energy Physics Technical Safety Forum 20 Current and Future Issues in Radiation Protection Control of Natural and Accelerator- produced Radioactive Material (NARM)  Issue in U.S. because of classification of material  Legislation before Congress to give responsibility to the Nuclear Regulatory Commission  Probably not an issue internationally

11 April th International High-Energy Physics Technical Safety Forum 21 Current and Future Issues in Radiation Protection Clearance of material that may be slightly radioactive  Removal of radioactive materials from regulatory control  IAEA Basic Safety Standards and Safety Guide No. RS-G-1.7 make recommendations internationally  NCRP Report No. 141 makes recommendations for the U.S.

11 April th International High-Energy Physics Technical Safety Forum 22 Current and Future Issues in Radiation Protection Future changes in regulations controlling:  Exposure of workers & public  ICRP proposal for 2005  Exposure of ecological species  ICRP Committee 5  Decommissioning & disposition of waste material  NCRP Annual Meeting 2005

11 April th International High-Energy Physics Technical Safety Forum 23 Current and Future Issues in Radiation Protection Disposition of low activity radioactive material  Risk informed  Systems approach using Probabilistic Risk or Performance Analysis  IAEA Guidance  NCRP Report No. 139  Single regulator  Cost effective disposal, not necessarily recycling or reuse

11 April th International High-Energy Physics Technical Safety Forum 24 Summary Radiation dose recommendations for occupational exposures have evolved as more information is gathered on the effects of radiation on humans. Current recommendations offer protection at a risk level of a few x annually and 1 % lifetime. Radiation presents a risk to workers that is similar to other industrial hazards. The control of other hazards might benefit from the application of principles applied to the control of radiation hazards.

11 April th International High-Energy Physics Technical Safety Forum 25 Summary Exposure guidance for people and species in the environment is not likely to change in the next few years. There is a need for international acceptance of clearance levels and risk informed disposition regulations for potentially radioactive material.