Jabiluka Radiation Exposures Part 1 : Public

The following concerns the radiation exposure which is predicted to arise from the workings at the Jabiluka/Ranger site. It is based on the Federal Government agency, Environment Australia (EA), response to the environmental impact statement of Energy Resources of Australia.

EA notes (p.95) that the combined radiation dose from Ranger and Jabiluka operations to "occupants of Mudginberri is predicted to be approximately 0.25milliSievert (mSv), or 25% of the applicable dose limit". The dose ‘limit’ referred to is the recommended dose of 1mSv as laid down by the International Commission on Radiological Protection (ICRP). The ICRP limit is the total dose which should arise from all man-made sources of radiation exposure, excluding medical procedures. ICRP limits are not legally binding (the Commission has no regulatory powers). However, as a signatory to the statute of the International Atomic Energy Agency, Australia, must not exceed ICRP limits.

A number of countries have erred on the side of caution and have set limits below the ICRP exposure levels. The German limit for doses from all nuclear sites is 0.3mSv per annum and in the US the limit is 0.25mSv – the same level as the predicted dose from the combined Jabiluka and Ranger operation. In the UK, the exposure limit from any single installation is set at 0.3mS. However, the UK’s National Radiological Protection Board has recommended that maximum exposure to an individual from all sites should be changed to 0.3mSv.

EA also notes (p.95) that the dose limit from the Jabiluka/Ranger operations may have been underestimated, and that doses of 0.49mSv may arise and that in some instances members of the public may even be exposed over the 1mSv limit!! The limits set for the Jabiluka/Ranger proposal could, therefore, be:

Monitoring in the UK shows that doses to residents near the massive reprocessing and nuclear power complex at Sellafield plant are less than the predicted doses at Jabiluka/Ranger. According to the Ministry of Agriculture, Fisheries and Food (1994) the dose received in the UK as a result of Sellafield range from 0.04mSv to 0.14mSv. Sellafield provides an important comparison as it is world’s largest routine discharger of radioactive waste.

At the Lucas Heights reactor site in Sydney, the Australian Nuclear Science and Technology Organisation have (self) imposed a dose limit of 0.3 mSv per annum. ANSTO claims the doses to the most exposed residents living near the site are approx. 0.013mSv – almost 20 times less than the lowest dose estimated from the Jabiluka/Ranger proposal.

Jabiluka radiation exposures: Part 2 Workers

In 1990 the ICRP revised the permitted radiation exposure for radiation workers downwards from 50mSv to 20mSv per annum. The ICRP also recommended that workers might be allowed over 20mSv in any given year, but only if the exposure in any five year period did not exceed 100mSv.

However, by 1990 the majority of nuclear workers in the developed world were already receiving less than 20mSv per annum, with many been exposed to less than 10mSv. Unions in the UK nuclear industry have called for annual dose limits to be set at 10mSv per annum. If it is believed possible to achieve this in a country which has large scale power and reprocessing plants then it should presumably be achievable in Australia.

However, following the ICRP’s recommendation for lower worker exposures there was an attempt by the nuclear industry to lobby to keep higher exposures for uranium miners. It was claimed that no uranium mine – particularly an underground mine – could meet the new levels. This is relevant to Jabiluka, which is not only an underground mine, but is one of the most radioactive ore bodies in the world. Research has shown that most radiation exposure (80%) in uranium mines arises from internal exposure due to inhalation of radon gas. The remaining 20% exposure is external and arises from gamma radiation from the ore body. However, with Jabiluka the exposure may be split 50/50 between external and internal radiation exposure. At Jabiluka protection from the highly penetrating external gamma radiation sources will be difficult to protect against. That the mine is underground will probably also result in higher exposure to radon gas than in an open cut mine because ventilation is not as effective as direct ‘venting’ to the atmosphere.

Despite these problems, ERA estimates that worker exposure will be less than 20mSv per annum. However, ERA also concedes that due to changes in radioactivity levels in the ore body the potential for increased radiation exposure might arise. Unfortunately the NH&MRC’s 1995 recommendations allow for worker doses at higher levels and for longer periods than the ICRP recommendations., The NHMRC states doses may be increased when "in exceptional circumstances, a temporary change in the dose limitation requirements is approved…." Among other things,. the regulations allow for a radiation dose of 50mSv per year for five years - a total exposure of 250mSv or just over one-quarter of a worker’s recommended lifetime dose. Workers could, therefore, be exposed for several years to 50% more than the ICRP maximum limit – far higher than the maximum acceptable risk posed by the 20mSv limit.

Jean McSorley, March 1998.

For further information contact the author on mcsorley@compassnet.com.au. It should be noted that comments on steps to increase safety should not be taken as an endorsement of the activities of the uranium mining industry.

Many thanks to Jean McSorley for supplying this article to SEA-US Inc.
Page last updated October 31, 1998.
Back to the SEA-US Front Page

Copyright © SEA-US 1998