J-value assessment of the cost effectiveness of UK sheep meat restrictions after the 1986 Chernobyl accident.

Following the accident at the Chernobyl Nuclear Power Plant in 1986, the United Kingdom Government imposed restrictions on the consumption of sheep meat that became contaminated by nuclear fallout to ensure it was extremely unlikely that any consumers would receive an unacceptable dose. The international context for the restrictions is summarized and a brief review of the strategies employed by the UK is presented. An analysis using the J-value framework, including the de minimis quantum of life expectancy, is made of the cost effectiveness of the sheep meat restrictions in force until 2012, in terms of 4 categories of consumer ranging from the average to the extreme. The paper shows that the risk to the general population was very low indeed at the time the restrictions were removed in 2012. Retaining the restrictions for an extra year, would have averted the dose to the average consumer by a fraction of a microSievert, corresponding to a gain in life expectancy of 8 s. Meanwhile for the ICRP Representative Person, the gain in life expectancy from retaining the restrictions for an extra year ranged between 17 and 25 s. These gains are nugatory, as they are a factor of between 8 and 23 below the de minimis quantum of life expectancy. This new measure provides a meaningful quantitative criterion for judging when the radiation exposure of a large population is trivial in the sense used by the ICRP. The gains in life expectancy for the Field Representative Person and the Extreme Consumer were above the trivial level, but the associated J-values were 10 and 40, an order of magnitude or more above the value of unity where a case could be made for retaining the restrictions for another year. The high J-values and/or de minimis life expectancy ratios suggest that the food restrictions could almost certainly have been ended earlier. Also discussed are: the choice of the Representative Person, the role of intervention levels, the extent to which conservatisms in analysis are warranted and how socio-political factors in decision making can be taken into account in a transparent way. [ABSTRACT FROM AUTHOR]