MAFF FISHERIES SCIENCE AND TECHNOLOGY APPRAISAL (STA)
PROJECT SUMMARY (INTRAMURAL)
Project Title:THE RELATIVE SIGNIFICANCE OF HISTORICAL AND CURRENT DISCHARGES FROM SELLAFIELD AS SOURCES OF PRESENT HUMAN RADIATION EXPOSURE
Project Code:AE0117 / Commission:Aquatic EnvironmentTopic:Scientific support for Radioactive Substances Act 1960
Classification (Tick appropriate line)
Primary Purpose:
A. General Support for ResearchB. Government ServicesC. Policy Support
D. Technology SupportE. Technology Transfer
Cabinet Office Category:
(Frascati)
Non R & DApplied Strategic R & DExperimental Development
Basic ResearchApplied Specific R & D
R & D NABS Code: / MINIM Programme:Contractor Details
Project Leader:K S Leonard, P J Kershaw / Contact Address: / LowestoftProposed Starting Date:April 1993 / Duration:5 years
Actual Start Date:April 1993 / End Date:March 1998
1. Submitted By:Date:
(Signature DDFR)
Customer and Contractor Agreement (See also Information Pack, Section 4)
2. DFR undertakes to carry out the work specified in the STA, in conformity with the Objectives set out in Section B2; and to meet the Targets/Outputs listed in Section B4, in return for the allocation by the Customer of the funding level specified in Section B8.
Signed Director, DFR______Date:
3. The Customer approves this project specification and undertakes to provide the financial resources specified in Section B8.
Signed Grade 5 Customer______Date:
Policy Division:
Summary Objectives: To differentiate the relative importance of past (historical) and current authorised discharges of radionuclides to the sea from Sellafield as sources of present human radiation exposure, and to quantify the separate contributions in accordance with the new philosophy of dose constraint as recommended by the ICRP.
Key Customer Purpose: To enable MAFF to review, on the basis of the best scientific information, its policies under RSA 1960 on the authorisation of current discharges to sea from Sellafield, and to provide a continuing assessment of the hazard arising from past discharges for which intervention measures might be appropriate.
The relative significance of historical and current discharges from Sellafield as sources of present human radiation exposure.
A:CUSTOMER REQUIREMENTS
A1.Policy Rationale
Under the Radioactive Substances Act, 1960, the Ministry issues authorisations permitting the disposal of low-level liquid radioactive waste to the aquatic environment. MAFF is also responsible for inspection, monitoring and dose assessments of discharged radioactive wastes to ensure that potential risks both to the living resources in the marine environment and to human health are sufficiently and effectively controlled.
A2.Policy Objectives
To further develop the scientific foundation for the assessment of the risks of long-lived radionuclides to both the marine environment and human health, and thereby to ensure that policy decisions on radioactive waste management are made with reduced uncertainty on the basis of the best scientific information available.
A3.Reasons for Funding by the Ministry
MAFF continues to require high quality information concerning the identification of the relative radiological implications of current and historical authorised discharges in critical exposure pathways. The information obtained will ensure that MAFF, in support of statutory obligations, is able to fully defend its approved authorisations against less informed critics and be able, as necessary, to predict actions for future authorised discharges and/or provide an indication of the risk from historic discharges for which intervention measures might be appropriate.
MAFF has contributed significantly towards the development of a capability to predict future concentrations of long-lived radionuclides in aquatic systems and hence doses to critical groups, through the completion of substantial investigations into the behaviour and analytical determination of radionuclides in the environment. It is appropriate that, to demonstrate a continuing commitment to effective and defensible waste management polices, these studies should be conducted by the Ministry.
A4.Benefits
1. Provide valuable information to evaluate dose, and hence risk, from both currently authorised and historical radioactive discharges.
2.Improve and consolidate the scientific input to the development of policies on the practice of radioactive waste disposal to sea.
3.Further demonstrate, in this politically sensitive area, the continuing commitment of Government to the protection of the aquatic environment.
4.To demonstrate, at national and international fora, an ability to support the best practicable environmental options (BPEO) for the management of liquid effluents containing low levels of radionuclides and provide suitable recommendations for the environmental monitoring programmes.
A5.Options
i)No action
It could be perceived that MAFF was neglecting its commitment to base waste management policies on BPEO and failing to identify the radiological implications of both current and historical authorised discharges in critical exposure pathways in accordance with the philosophy of dose constraints which is now recommended by the International Commission on Radiological Protection (ICRP). National and international criticism may result if no action were taken in this area.
ii)Using fewer resources
Use of fewer resources would compromise the scientific validity of the programme, by seriously limiting the information available to allow disaggregation of the impacts of current and historical discharges on human exposure, and delaying the provision of advice based on improved scientific understanding.
iii)Alternative approaches
No alternative approaches have been identified other than extra-mural commissioning of equivalent work. However, no other individual organisation has the breadth of expertise and background available at DFR to ensure that work is carried out to a satisfactory standard and in the context of policy concerns and statutory responsibilities.
B:CONTRACTOR PROPOSAL
B1.Introduction
In support of its statutory responsibility, MAFF carries out monitoring to evaluate the impact of authorised low-level radioactive discharges into the aquatic environment and to assess the extent of consequent human radiation exposure. The past decade has seen significant decreases in discharges of liquid wastes to the Irish Sea. The rate of decrease of doses to the critical group following reductions in discharges depends upon the time period during which the influence of prior discharges is significant. It is important to establish the time scales of this influence not only to provide a knowledge of the short-term future behaviour of transuranics and resultant doses, but also as an input to decisions on appropriate further treatment plants and consequent revision of discharge authorisation.
A large proportion of the long-lived radionuclides (e.g. plutonium and americium) from historical discharges reside in the muddy seabed sediments of the eastern Irish Sea and have the potential to influence the exposure to critical groups for some considerable time in the future. Reductions in current discharges following the operation of new treatment plants or procedures will not result immediately in proportionate reductions in exposures.
B2.Scientific Objectives
This project will involve work to predict the future concentrations in water and on sediment particles of long-lived radionuclides (e.g. plutonium and americium) from both current and historical discharges in the Irish Sea. The capabilities and shortcomings of existing predictive tools and models will be evaluated in the context of modelling both current and historical discharge scenarios. As required, existing models will be developed by the inclusion and quantification of additional environmental processes and predictions will be validated with observed radionuclide distributions. Consequently, it will be possible to justify any necessary actions of remedial measures and revision of discharge authorisations.
B3.Work Programme
Within DRF, time scales for dilution and dispersion of radionuclides relevant to short-term predictions have been investigated using empirical methods and for longer time scales remobilisation of radionuclides have been examined with the aid of a compartment model (MIRMAID). A further mechanistic model has been developed at Harwell. Initially a desk study is required to review the applicability of these models in the context of current and historical discharges.
A programme of experimental laboratory work and field sampling is required to further assess the impact of current discharges using effluents and environmental materials to simulate existing discharge practices. The historic behaviour of discharges will also be re-evaluated from MAFF's previous investigations of radionuclide distributions in the water column, suspended particulate materials and sediment samples. The results obtained from another STA, the fate of Irish Sea sediments, will also be evaluated to provide further input to describe the behaviour of historical discharges.
B4.Targets and Outputs
T1. Carry out a desk study to evaluate the applicability of existing DFR models for the prediction of future concentrations of radionuclides in the marine environment.
Renew contact with Harwell to consider the approach of their mechanistic model.
Consider future requirements to overcome the shortcomings of models.
Complete interim report, Apr 1994.
T2. Identify and evaluate applicability of MAFF historical data for use in existing models,
Apr 1994 - Dec 94.
Interpret historical data for modelling purposes and identify incomplete data,
Dec 1994 - Sep 1995.
Validate models with existing data, Oct 1995 - Sep 1996.
Complete interim report, Dec 1996.
T3. Design, develop, and complete trials concerning laboratory experiments to simulate current discharges, Apr 1994 - Mar 1995.
Carry out programme for collection of environmental samples, Oct 1994 - Mar 1996.
Carry out experimental work to assess the impact of current discharges, Apr 1995 -
Oct 1996.
Identify and quantify important processes for inclusion in models.
Complete interim report, Dec 1996.
T4. Initiate model development to include new processes and rates. Oct 1996 - Mar 1997.
Simulate effects of current and historic discharges, Apr 1997 - Dec 1997.
T5. Final report, Mar 1998.
B5.Other related work elsewhere in the UK or overseas
Studies of the behaviour of artificial radionuclides in the marine environment are carried out in a few research institutes and university departments in the UK and in laboratories overseas.(e.g. Scottish Universities Research & Reactor Centre, Lancaster U and Harwell ) and radiological assessments are undertaken by others (e.g. NRPB). However, MAFF has accumulated extensive experience and skills over many years in both radionuclide behaviour and dose assessments of the critical group, and is able to provide an appreciable range of expertise concerning sample collection, radioanalytical assay, provision of data and modelling, all of which are required to successfully complete this programme.
B6.Uptake and Implementation
The project will produce high quality information in support of MAFF's statutory responsibilities under the Radioactive Substances Act 1960 to ensure that policy on the control of future radioactive discharges, and potential intervention action in respect of the legacy of historic discharges, is based on the best available understanding of the consequences for human health and the environment. It is likely that Sellafield will continue to remain a controversial topic, attracting public and political attention. MAFF needs to be able to demonstrate that it is fully committed to the preservation of environmental quality.
B7.Risks
The attainment of the work described and targets will be achieved as long as the projected staff levels and resources are maintained. However the proposed work to assess existing MAFF historical data (target 2) is dependant upon filling an existing vacancy (HSO - post 8) and if not recruited other targets are likely to be delayed.
B8
PROJECT NUMBER: / AE0117PROJECT TITLE: / The relative significance of historical and current discharges
from Sellafield as sources of present human radiation exposure
STA FEC COST DETAILS / £'000
1993/94 / 1994/5 / 1995/6 / 1996/7 / 1997/8
Staff: / 121.8 / 121.8 / 121.8 / 121.8
Current: / 7.5 / 13 / 14 / 10
Capital Spend: / 25 / 7.5 / 8 / 0
MAFF vessel: / 0 / 37.8 / 37.8 / 0
Charter vessel: / 0 / 0 / 0 / 0
Total / 154.3 / 180.1 / 181.6 / 131.8
5% Seedcorn Surcharge / 7.715 / 9.005 / 9.08 / 6.59
5%
FEC TOTAL / 162.015 / 189.105 / 190.68 / 138.39
a) STAFF DETAILS
(Man year)
SP & T / 2.4 / 2.4 / 2.4 / 2.4
Other / 0.05 / 0.05 / 0.05 / 0.05
Staff Totals / 2.45 / 2.45 / 2.45 / 2.45
b) RESEARCH VESSEL DETAILS
MAFF vessel days / 0 / 5 / 5 / 0
Charter vessel days / 0 / 0 / 0 / 0
Total vessel days / 0 / 5 / 5 / 0