Updated NCRP Population Exposure Information and Implications to RETS-REMP Issues

Ken Sejkora Entergy Nuclear Northeast – Pilgrim Station Presented at the 19 th Annual RETS-REMP Workshop South Bend, IN / 22-24 June 2009

NCRP Report 93

   Published in 1987 Assessment of the average exposure of members of the United States population from all sources of ionizing radiation Considered six main source categories:       Natural radiation Occupational (radiation workers) Nuclear fuel cycle Consumer products Miscellaneous environmental sources Medical diagnosis and therapy

NCRP Report 93 - Method

  For each source type, the product of the estimated number of people exposed and the average effective dose equivalent received from that source is expressed as the collective dose from that source -- man-mRem, man-Sv Collective dose from each source is then divided by the entire United States population to obtain the contribution from that source to the average effective dose equivalent for a member of the United States population – mrem, Sv

NCRP Report 93 - Method

  Dose for each exposure type was then divided by total to determine relative fraction from each type Resulting Pie-chart has been used by radiation protection personnel to emphasize importance of natural sources to an individual’s exposure… helps place things into perspective

From NCRP Report No. 093, “Ionizing Radiation Exposure of the Population of United States” (1987)

NCRP Report 93 - Summary

 Average dose to individual was 360 mrem/yr   Approximately 54% of dose was attributed to radon An additional 27% attributed to other natural sources (cosmic, terrestrial, internal)    Total ~83% attributed to natural sources Medical comprised ~15% Dose from nuclear power was grouped into a category comprising <1%

NCRP Report 160

     Published in 2009, based on data from 2006 NCRP felt it necessary to re-assess population exposure and sources due to increase in medical applications over the past two decades New report provides a more detailed delineation of medical exposure Similar approach to NCRP 93, where collective population dose is divided by total population size Pie-chart similar to that in NCRP 93

From NCRP Report No. 160, “Ionizing Radiation Exposure of the Population of the United States” (2009)

NCRP Report 160 - Summary

 Average dose to individual is 620 mrem/yr    Approximately 37% of dose was attributed to radon An additional 13% attributed to other natural sources (cosmic, terrestrial, internal) Total ~50% attributed to natural sources  

Medical comprised ~48%

Dose from nuclear power was grouped into a category comprising <0.1%

From NCRP Report No. 160, “Ionizing Radiation Exposure of the Population of the United States” (2009)

Why is this Important to RETS-REMP?

    RETS-REMP personnel are recognized as radiation protection professionals!

We need to understand the importance of natural radiation’s contribution to overall exposure We should discuss & emphasize the contribution of natural radiation exposure in our Annual Radiological Environmental Operating Reports We need to place the dose impact from plant operations into overall perspective to other sources of exposure

“Good” Radiation vs. “Bad” Radiation

  In the public’s eye, there are two types of radiation   “Good” radiation benefits humans… any medical exposure is “good” radiation “Bad” radiation is detrimental to humans… any industrial/commercial exposure is “bad” radiation; many even include natural exposure in this category Unfortunately, some professionals (medical doctors) subscribe to the above delineation   Cranial CT scan ~3300 mrem, Abdominal CT ~8000 mrem

Dose vs. Risk

   Recognize that dose is dose, and a mrem carries the same risk whether it occurs from medical exposure or natural exposure or from power plant operation We need to initiate change by encouraging the professional community to adopt a risk-based approach to radiation protection and standards, and compare risk from commonly-accepted activities Regulations and regulatory guidance need to be shifted to a risk-based approach… EPA does this to a certain extent for non-radiological contaminants in drinking water

Summary

   NCRP has revised its assessment of radiation exposure to the general public… we need to use new information to our advantage The average American’s dose has increased from 360 mrem/yr in 1986 to 620 mrem in 2006, mostly from medical exposure Dose from natural sources of radiation account for ~300 mrem/yr, compared to less than 1 mrem/yr from nuclear power

Summary

  The radiation protection and medical professions need to recognize any detrimental effects of radiation are equal regardless the source of radiation… no more acceptance of “good” vs. “bad” dose We need to advocate regulators to adopt risk-based approaches to radiation protection standards and guidelines

Questions?