Updated NCRP Population Exposure Information and Implications to RETS-REMP

Issues

Ken SejkoraEntergy Nuclear Northeast – Pilgrim Station

Presented at the 19th Annual RETS-REMP WorkshopSouth 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?