Radiation Protection Today Winter 2021 - Page 16

WORDS FROM THE WISE

Uranium Ore from Scotland
Colin Partington MBE is an Honorary Fellow and Past President of SRP . He was Head of Safety at Sellafield for 12 years and was awarded an MBE for services to radiological safety . In this article , he recounts how something as seemingly innocuous as a geological specimen can be sufficiently radioactive to warrant special precautions .

This is a story of how I , Health and
Safety Manager at a nuclear power station , came to be digging up uranium ore in Scotland , and how we learned lessons from it .
In 1982 , I moved from Sellafield to the Chapelcross nuclear power station near Annan in the Scottish borders . Not long after I joined Chapelcross , in 1983 , there was a TV programme about Sellafield , which brought everyone ' s attention to the risks from radiation , and frightened people who thought they were close enough to Sellafield to be affected by an accident there . Those who actually lived close to Sellafield , which is in west Cumbria , usually knew someone who worked there , and didn ' t feel the same risks as those a bit farther away , such as Kendal , Lancaster and southern Scotland .
The curator of Dumfries Museum became nervous about displaying samples of uranium ore ( pitchblende ) and asked for advice from the Radiation Protection Adviser ( RPA ) at Dumfries Hospital . He felt he knew little about the risks , and so rang me up . I was unaware of the occurrence of pitchblende in southern Scotland and offered to take the samples off his hands and arrange to have them displayed in the Sellafield Visitor Centre . Unfortunately , the curator was unable to “ dispose ” of the samples to me ( they were owned by the museum ), but offered to arrange for me to be taken to where the samples were collected in the late 1960s .
So , a couple of weeks later , the previous and current curators and I headed to the foothills of Criffel to find pitchblende , armed with a 14lb sledgehammer , chisels , geological hammer , a rucksack and , of course , radiation detectors .
Criffel is a mountain in Kirkcudbrightshire , Dumfries and Galloway and is some 1870 ft high , although it looks higher because of its isolation from other hills . Geologically , Criffel is a pluton , a mass of granite that welled up towards the surface but never broke through . In pushing its way up , it cracked the overlying sedimentary rocks , and as the granite cooled , liquids rich in minerals flowed along the cracks and solidified according to their melting points . Subsequent erosion took away the sedimentary rocks to expose the
AWRE Laundry granite as a hill , surrounded by mineralised country rocks . Many of these minerals have already been mined – lead , tin , etc .
A geological study in the 1950s or 60s identified some 57 prominent veins of uraninite ( pitchblende ) surrounding Criffel , but concluded that access and quantities made commercial mining uneconomic .
Finding the ore veins was easy with my monitoring instrument . The dose rate above the vein on the coastal road to the west of
Dosimetric units rem stands for roentgen equivalent man , which is the non-SI unit of equivalent , effective or committed dose . The equivalent SI unit is the Sievert ( Sv ), which is now used worldwide , other than in the USA .
100 rem ≈ 1 Sv 1 rem ≈ 10 μSv 1 mrem ( millirem ) = 0.001 rem ≈ 10 μSv
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