​Nuclear Restoration Services (NRS) Hunterston A site gaseous discharges variation application
Application details
Hunterston A is a twin reactor Magnox power station. It was shut down in 1990, and defueling was completed in 1995. The site is now being decommissioned by Nuclear Restoration Services (NRS), which is a process to dismantle and decontaminate redundant facilities, focussing on the treatment and removal of both radioactive and non-radioactive wastes.
NRS Hunterston A was originally authorised for the disposal of radioactive waste under the Radioactive Substances Act 1993 (RSA 93) by SEPA. With the introduction of new legislation on 1 September 2018 known as the Environmental Authorisations (Scotland) Regulations 2018 (EASR) the original RSA 93 authorisation was superseded and a new permit for the management of radioactive substances (EAS/P/1173609) came into effect on 1 April 2019.
In 2014 the site began a programme of works to remove Intermediate Level Waste (ILW) from the Solid Active Waste Building (SAWB) bunkers.
To allow NRS Hunterston A to encapsulate the waste a facility has been built on the site called the Solid Intermediate Level Waste Encapsulation (SILWE) facility. This new facility requires the operation of an active ventilation system to discharge gaseous discharges. Therefore NRS Hunterston A are applying for a new authorised radioactive gaseous waste discharge point at the facility to be included within the site permit.
To allow NRS Hunterston A to store the waste on site after encapsulation, a facility has been built on the site called the Intermediate Level Waste Store (ILWS). Therefore NRS Hunterston A are applying for a new authorised radioactive gaseous waste discharge point at the facility to be included within the site permit. Storage of Intermediate Level Waste on site is in line with current Scottish Government Policy.
NRS have undertaken a review of all of the current facilities on the site and the associated levels of gaseous discharges against the current site EASR permit. NRS have considered gaseous discharges both at this time, as well as a future projection of potential site gaseous discharges due to the encapsulation of the Intermediate Level Wastes from the bunkers, as well as other planned work on the site going forward.
As a result of this review NRS have determined that Hunterston A require to increase the site gaseous discharge limits set in the permit.
The proposed limits have been modelled and assessed by NRS to determine whether there would be any environmental impact. The models were used to assess the radiological dose to the public, to non-human species as well as the transboundary dose to the nearest country outside the UK. All the results were well below the public dose limit of 1000 µSvy-1 and the screening value of 10 µSvy-1 for the protection of non-human species.
Therefore as part of this application NRS has concluded that there are no actions required in relation to The Transboundary Radioactive Contamination (Scotland) Direction 2021. This direction effectively replaces what would have been required under Article 37 of the EURATOM Treaty that would have been required prior to EU Exit. We will check the submitted calculations as part of the determination process.