The IRR99 and the IRR85 requires employers to keep exposure to ionising radiation as low as reasonably practicable.
VJ Battery at Eskemals in the early years was essentially a traditional open butt with the addition of a roof and extract ventilation from each side of the butt. this allowed the spray back of aerosolised DU and fragements through the open air onto a apron in front of the butt.
To quote from the reports :-
Safety Services Organisation MOD(PE) November 1983, The distribution of Depleted Uranium releases at P&&EE Eskmeals, excluding appendices.
Report summarising the measurements taken at VJ Butt P&EE Eskmeals of Depleted Uranium in air during the period 1981 to 1982.
"The penetrator on impacting with the target produced pyrophoric fragments which rapidly disintegrate and. there is a spray back-up the range over an angle of 20 degrees for a distance of 60 metres."
"Total activity in air measurements taken outside the butt indicate that DU is being released to the environment at levels above the DAC for a period of time after firing. It is not possible to quantify the amounts.". DAC "Derived Air Concentration" ICRP 30
"The DU dust was found to be well within the respirable size range, dust particles of this size have very long settling times and can remain airborne for very long periods of time and if allowed to disperse from the butt may travel many hundreds of meters."
This is the Department of Defense Superbox DU firing facility at Aberdeen Proving Ground Maryland USA. As can be seen the facility offers almost complete containment. It includes a flight tunnel with a drop down door. The Superbox facility is seen as an example of a facility that reduces exposures to the public and workers outside the facility to a level that is ALARP
The conclusion is that that in the early years of the firing programme the MOD failed to meet its legal duty to restrict exposures to as low as level as reasonably practical. It is also interesting to consider that that the VJ Battery at Eskmeals was probably very quick and cheap to build compared to the Superbox facility in the USA.
It is now also clear that the MOD failed to seek letters of agreement from the Environment Agency for the discharge of DU to atmosphere from VJ Battery at Eskmeals. This was in breach of the MODs' own policies.
Later years of the firing programme at Eskmeals
DRPS Report "Comparison of Kirkcudbright and Eskmeals Environmental Monitoring Data with Generalised Derived Limits for Uranium" June 2002 mentions that a tunnel was added to the face of VJ Butt in order to reduce discharges of DU to the environment. This acknowledged that the original firings at VJ did not comply with the requirement to restrict exposures to as low as level as reasonably practical.
1: HSE Reducing risks protecting people 2001