David Bennett 2 April 2009

1. Disposal Facility & Engineered Barrier System (EBS) Design PRISM: Practical Illustration and use of the Safety Case Concept in the Management of Near-surface Disposal David Bennett 2 April 2009

2. Design Working Group • David Bennett DavidBennett@TerraSalus.co.uk • Nadja Zeleznik Nadja.Zeleznik@gov.si • Bernhard Großmnn Bernhard.Grossmann@dmt.de • Gyula Dankó gdanko@golder.hu • Sandi Virsek Sandi.Virsek@gov.si • Michael Tichauer Michael.Tichauer@irsn.fr • Peter Salzer salzer@decom.sk • Janez Perko JPerko@sckcen.be • Dody Ivan dodik@bgu.ac.il • Marija Kališnik Marija.kalisnik@gov.si • Stasys Motiejunas S.Motiejunas@rata.lt

3. Working Group Objective • To share information and communicate good practice on: • How decisions on the design, extension and improvement of near-surface waste disposal facilities can be informed by, and justified using the Safety Case • How the Safety Case can be used on an ongoing basis to support management decisions on facility design and modification • We will also acknowledge the role of the EIA process in the early stages of facility design and implementation

4. Proposed Work Areas • Designing and upgrading near-surface radioactive waste disposal facilities using the safety case: 1a) Review of past and current practice on design • Will take examples from near-surface facilities in the WG’s experience • Will also seek information to cover a wider range of facilities and waste types • Will actively seek assistance from other project participants and relevant organisations • Have developed some terms of reference for this ‘data gathering’ • Will also review relevant IAEA and NEA documents

5. Proposed Work Areas 1b) Analysis of review findings to identify lessons on good practice in facility design • Have begun to identify and consider the many factors that affect facility design • Will describe expectations of facility design information at different stages of facility development • Will describe relationships between facility and EBS design and the safety case at different stages • Will discuss optimisation of EBS (ALARA) • e.g., iterative schemes

6. Terms of Reference for Data Gathering • Safety / design philosophy • Both for operations and post-closure • General description of facility development history, e.g: • Waste type and inventory • Influence of regulations/guidance • Commentary on reasons for the design of each engineered component (e.g., package, backfill, walls, cap, drains etc) • e.g., size, shape, material, monitoring • History of any design changes and their rationale • Functions assigned to engineered components (if any) • Treatment of barriers and barrier degradation in the safety case / assessment

7. Facilities Covered by Working Group • Dessel, Belgium • CSM, CSA, Morvilliers, France • Konrad, Germany • Püspökszilágy & Pecs, Hungary • Maišiagala & new prototype near-surface repository, Lithuania • Mochovce, Slovakia • Slovenian silo concept • LLWR, UK

8. Broadening Our Scope • Borehole facilities • Previous IAEA projects • South Africa, Russia, US • Mine tailings • Previous IAEA projects • Wismut? • Forsmark, Olkiluoto type facilities • Swedish/Finnish input • Cavern type facilities • Richard – Czech Republic? • ‘Deeper’ concepts for LLW/ILW? • France, Canada?

9. Requirements & Constraints on Design • Safety requirements (e.g., dose constraint, ALARA) • Design philosophy (passive safety, isolation, containment….) • Waste type / characteristics • Stakeholders (public, local communities, scientific community and committees, others) • Past practice / experience • Operational factors (e.g., infrastructure, waste handling, waste QA checking) • Site characteristics • Monitoring • Knowledge of any pre-existing facilities on the site (disposal and other) • Safety assessors, facility operators • Availability of barrier materials & technology • Barrier performance/degradation • Safety assessment assumptions and results, existing WAC • Project timescales and feasibility • Allowing for flexibility and iterations of the safety case • Costs vs benefits (of alternatives) • Regulations • Government & Policy

10. Stages (will vary by country and site) Site screening, investigation, characterisation, selection Design options and concept selection Detailed design Construction Operational phase Refinement of design Upgrading if necessary Closure Institutional Control Plan to discuss the design and related safety case activities for each stage Will consider a range of facility types Will consider the relative importance of various factors & influences on design at each stage Will work closely with Group 1 on timeline Design in the Facility Lifecycle Design & assessment overlap, iteration, variation in stages

11. Planning • Roles and responsibilities of group members defined and agreed • Provisional schedule outlined • Deliverables identified

12. Provisional Schedule • Terms of reference for data gathering (drafted Apr 2009) • Data gathering (by Oct 2009) • Working group meeting to discuss findings and begin drafting report (Nov-Dec 2009) • Improve report draft of report (Spring 2010) • Presentations to next plenary in Spring 2010 • Workshop style day

13. Main Deliverables • Terms of reference for data gathering • Notes on relevance to the group’s work of existing IAEA and NEA documents • Papers on various disposal facilities • Table of contents for report • 2 part structure as described above • Detail to be developed • 1st Draft of report

15. Issues List • Project website • Project newsletter • Draft IAEA safety guides

16. Interfaces with other WGs • Generic WAC • Design changes to manage uncertainties

17. Roles & Responsibilities • Review of ISAM, ASAM documents and other IAEA documents on engineered barriers, facility closure and design • Put relevant documents on website (all) • TR433, upgrading of NS repositories, SR35,surveillance and monitoring of NS repositories, ASAM cross-cutting report on engineered barriers • Be aware of draft safety guides (DS334, 354, 355, 357) (SM / all) • Close cooperation with Group 1 at early stage (DB) • Data gathering on our facilities (all) • Send results to DB by 30 September, copy to others in group • Everyone to read before group meeting

18. Roles & Responsibilities • Arrange next group meeting (DB, DI?) • IAEA funding support (DB,JR) • 2 or 3 days to discuss findings and lessons • Prepare 1st draft of report (DB, GD, JP, PS) • Begin drafting at the meeting and continue after • Rest of group will review • Presentations to next plenary (all data gatherers, authors) • Ongoing communication with other groups via plenarys and Coordinating Committee