|30 September 2010
Mr Chris Clement, Scientific Secretary
International Commission on Radiological Protection (ICRP)
Re: WNA Comments on ICRP’s draft report ‘Lung Cancer Risk from Radon Progeny’
The World Nuclear Association (WNA) is pleased to submit comments from the global nuclear industry on the ICRP draft report Lung Cancer Risk from Radon Progeny”.
WNA membership includes the full range of enterprises involved in producing nuclear power – from uranium miners to equipment suppliers to generators of electricity. Our membership includes over 185 companies from over 30 countries. In total, it covers most of nuclear fuel cycle companies as well as nuclear utilities which contribute to over 90% of the nuclear generation electricity.
Of particular relevance to the subject ICRP draft report, the WNA membership covers over 90% of the world uranium mining production. This membership consists of all major uranium miners as well as many medium and smaller-sized uranium miners. The control of miners’ exposure to radon progeny is well incorporated as part of radiological protection programmes for uranium mines and mills.
As an integral part of nuclear activities, all WNA members give due consideration to the safe management of radiation health risk to people and the environment. The soundness, robustness and stability of the science as well as the practical knowledge and experience that underpin this risk are very important, including for the risk from radon progeny.
The companies of the global nuclear industry - and especially uranium miners - are therefore committed to offer worldwide industry leadership with a view to practically contributing to a sound evolution of the risk from radon progeny and of the related practical implementation. Below is a short list of our main comments on the subject ICRP draft report.
1. Main outcomes from most recent epidemiology studies and potential related policy-making implications – We noted that such studies appear to point to an increase in the risk from radon progeny by about a factor of two. We also noted that smoking is a key factor that influences this risk.
Given this and considering that a number of key epidemiological studies are upcoming, we would welcome an open dialogue with leading international organizations in this field (ICRP, UNSCEAR and IAEA) with a view to gradually build an international consensus on the best way forward concerning the evolution of this risk - as deduced from epidemiological studies – as well as the subsequent policy-making implications.
We also see merit in carefully managing this development as maintaining stability and credibility in the international radiological protection system is of paramount importance. In doing so, we are obviously very interested in learning more about new evidence and details which support a change in this risk.
We emphasize that during this transition, miners’ exposures to radon progeny at uranium mine sites will remain optimized and that this will still be the case afterward, when a new robust consensus has been reached on the risk from radon progeny.
On the grounds of regulatory stability, we therefore see a compelling case to keep using the current risk factor for radon progeny while the international consensus on this risk is strengthened.
In the meantime, we would see no issue in closely monitoring compliance of miner’s exposures with the applicable dose limits – by assuming that the risk factor for radon progeny is two times higher. We found that this option bears the necessary level of prudence prior to a formal move towards a significant change in the risk factor.
2. A new refined dosimetric approach by ICRP – We noted ICRP’s intention to move from the current epidemiological-based approach to a new refined dosimetric-based approach for the estimation of the risk from radon progeny.
We would be interested in knowing more about ICRP’s rationale in support of such a key change and about ICRP’s considerations of the related implications. It appears that ICRP is simply seeking to calculate doses from radon progeny’s radionuclides in the same way than it does for other radionuclides.
This intention is of great concern to us as we do not know if such an approach can be sound for uranium mining – which is probably one of the very few contexts where radon progeny doses are individually assigned to workers and are officially registered in national dosimetry records.
We know that the new dosimetric approach requires a refined characterization of mining workplaces for which there is not much recent data. We also know that gaining and analysing such data, with a view to develop and test the practical feasibility of the new dosimetric approach, will take a few years. In addition, both the calibration of this new approach (with the epidemiological approach) and its reliability will need to be examined carefully. That said, the global uranium mining industry is prepared to seriously investigate this matter (including conducting a few tests in some mines) over the next few years and to report on it to ICRP and others.
Assuming that a dosimetric approach can be practically implemented, we would still wonder if a dosimetric approach can be fully credible if it does not adequately account for smoking, which is by far the largest risk of lung cancer.
Above all, we stress that adopting a new dosimetric approach for radon progeny is premature and unnecessary. Retaining the current epidemiological-based approach provides a strong basis for standard setting and we therefore urge the ICRP to postpone and reconsider the adoption of the new dosimetric approach for radon progeny until further work is done in this area.
We noted that the potential increase in the risk factor for radon would have implications for the broader radiation protection system. In particular, care will need to be taken to help ensure that an appropriate balance in effort is maintained at controlling all types of exposure, given that an even larger portion of the public’s overall dose will now be due to the natural presence of radon in nature.
We stress that the new ICRP system of planned and existing exposure situations may be conceptually appealing, but needs further clarification to address the key issue of balancing effort to the actual risk from a given source of public exposure. The way that sources of radon are covered by planned and existing exposure situations is a case in point.
We count on the ICRP’s far-sighted views to initiate a serious reflection on re-balancing the system of radiological protection for the control of public exposure from diverse sources. The anticipated higher risk factor from radon progeny makes this reflection even more important.
We thank you for this opportunity to provide the global nuclear industry views on this ICRP draft report and we look forward to further engage with ICRP on this matter.
With kind regards,
WNA, Director for Environment and Radiological Protection
UNSCEAR: M. Crick;
IAEA: E. Amaral, R. Czarwinski, T. Colgan, T,. Boal;
WHO: M. Perez