The actual discharges from Sellafield cannot be measured directly by our authorities but the concentration of radioactivity from Sellafield in our coastal waters and in the Irish Sea is measured by the Nuclear Energy Board in conjunction with the Department of the Marine. This is an indirect method of measuring Sellafield discharges and the facilities for making these measurements exist already.
The same facilities will be used to measure any increase in concentration which may arise when THORP is fully commissioned and operational. The operators of this plant are of the opinion that there will not be a significant increase in discharges when THORP is operational, because additional treatment equipment has been commissioned.
The scientific assessment of the effects of Sellafield discharges is carried out by the NEB, principally on the basis that by estimating the dose arising to fish eaters and comparing this to international limits and doses from natural background, they can arrive at a conclusion.
The latest information on this may be found in the NEB annual report for 1989 and the NEB report entitled "Radioactivity Monitoring of the Irish Marine Environment — 1987". A report on radioactivity monitoring of the marine environment covering the years 1988 to 1990 will be published shortly, and it will show a continuing decrease in radioactivity levels in the Irish Sea, consistent with the reduction in discharges from Sellafield over recent years.