File ref Page 1 The Use of

File ref: Page 1

The Use of a Waste Conversion Index as a Long Term Performance Indicator for Civil Nuclear Liabilities Pauline Fawcett, BNFL 7 th European ALARA Network Workshop, Arnhem, The Netherlands, 29 - 31 October 2003 File ref: Page 2

Content l Reasons for the Index l. What the index comprises and how we calculate values l File ref: Uses of the Index Page 3

Waste Conversion Index Drivers Existing government policy (Cm 2919) and the “Managing the Nuclear Legacy” (Cm 5552) both require systematic and progressive reduction of hazard l l. As operators we need to develop a quantitative measure of hazard to be able to demonstrate and communicate hazard reduction to stakeholders File ref: Page 4

Waste Conversion Index l Started in Summer 2001 Original semi-quantitative Index developed by UKAEA l l l File ref: Quantitative index developed in conjunction with UKAEA Discussions held/buy-in sought from: – BNFL Senior Management and Operations – UKAEA – UK Regulators/NII/EA/SEPA – LMU Page 5

Waste Conversion Index - Criteria for its Development Should: l Reflect an emphasis towards passive safety l Be easy to calculate, maintain and explain l Accord with common sense l l Be capable of consistency across nuclear facilities l File ref: Reflect progress at various stages in waste retrieval programmes Avoid subjective criteria where possible Page 6

Definition of the Index The Index is a measure of the ‘potential to cause harm File ref: Page 7

Factors Included in The Index l The inherent hazard as measured by the quantity of material and its capability to cause harm l How easily it is spread about which includes its form along with its physical and chemical stability l The integrity of the barriers which prevent it being spread about File ref: Page 8

Waste Conversion Index - Calculation “Index Score” = Instantaneous Toxic Potential x Form Factor x Reactivity factor x Containment Factor l Once base data available, very quick and easy to update File ref: Page 9

Numerical Values for WCI Factors File ref: Page 10

Basis for the factors l Values ascribed using common sense and judgement l Logical basis but subjective l Span several orders of magnitude to reflect large difference in mobility of a gas and vitrified solids l Magnitude of the factors allows ITP to be sufficiently modified to reflect the projected benefits of changing form, containment or reactivity l Intention is to provide relative measure of hazard/passivity not absolute measure File ref: Page 11

Waste Conversion Index - ITP of Selected Plants File ref: Page 12

Waste Conversion Index - For Selected Plants File ref: Page 13

Waste Conversion Index - Its Uses As a means of demonstrating systematic and progressive reduction in ‘hazard’ and of communicating this progress. l As an output measure of programmes to retrieve and package waste l As a predictive tool and to answer ‘what if’ questions and compare different strategies/scenarios l As one of many inputs into an overall decision making process which will define the programme of work l File ref: Page 14

Waste Conversion Index - Potential Misuses The Index should not be used as the sole basis for: l Making decisions l Prioritisation between projects/ work programmes l Allocating funding between sites or within a site ALSO IT DOES NOT: l Accurately measure the safety or environmental hazards posed by a site File ref: Page 15

Summary l. A quantitative Waste Conversion Index has been developed l It allows hazard reduction to be measured and communicated l It has a logical scientific basis but the numerical factors applied are not rigorously underpinned l The Index has been calculated for a range of key inventories and been shown to agree with informed judgement l BNFL are using this Index to evaluate future work programmes for retrieval and treatment of waste File ref: Page 16