(516.5070) Nuclear Awareness Group The AWE update over radioactive and chemical contamination on and off their site dating from earlier years, contains some useful discussions on the relative seriousness and solvability of some of the chemical contamination problems. Sadly, when it comes to radioactive contamination we are back to the old game of hide and seek. Only those of us who know of Bq's (Becquerels) will be able to work out from the figures that there is a really serious problem. The rest of us, reading the text, would have no idea, it all sounds under control.
Plutonium
The most serious problem presented in the update is that of the former Radioactive Waste
Management Complex (A12). This complex was condemned in the Pochin Report (1978), so that the high
levels of Pu found recently in surface water drains has existed for many years, and has ample time
to migrate on and off site.
The actual figures quoted (for surface water drains sediment) are 500,000 Bq/kg (well actually,
they quote 500 Bq/g, but kg is the normal volume measured). To give some idea what this means, the
level found in the Thames sediment at the outfall of the AWE Pangbourne pipeline which carries Pu
waste to the river, is 2.4 Bq/kg.
We find it mind-boggling that although AWE have been regurlarly monitoring fresh water sediment
for Pu for years and years at six places on site and several off site, and coming up with averages
like 6 Bq/kg on site, while all the time the A12 was humming with thousands of Becquerels.
Unbelievably, the movement of groundwater from underneath the AWE site is only now being
evaluated.
AWE has "covered" over the whole A12 area and istalled new surface water catchment tanks. These
measures should stop the drains problem, but cannot alleviate the legacy from the past. The extent
of the off site legacy in soil should become clearer when Southampton University concludes their
sampling of the area in 2 years time.
During the presentation of their annual report AWE acknowledged the massive Pu contamination, but the audience was told that it had been "cleaned up, or is not mobile and is contained". However, when challenged on the contamination of the groundwater which cannot be cleaned up, the more accurate but worrying answer was given: that it will take 100 years to seep out of the base into the community. More high levels of Pu-1500 Bq/kg--were found in sediment of two natural pounds. The update calls this amount "small"--we don't agree. Until the new surface water tanks came into use last October, these pounds took the surface run off from the A12 area.
Tritium
Tritium leak problems are still holding up the discharge authorization procedure. The Environment
Agency has questioned a leakage from groundwater on site at AWE leaving the site via Aldermaston
Brook. AWE is still trying to establish the source. Two other locations with tritium contamination
were found. The tritium recovered from one is what constitutes the proposed one off dump into the
Thames--the levels involved were 1,900 Bq/kg.
Source: NAG Newsletter, August 1999
Contact: Nuclear Awareness Group,
8, Langborough Road, Wokingham, Berks. RG40 2BT, UK.
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