On PP11 Safety Approach

1. On PP11 Safety Approach Requirement Analysis • Personal info • Introduction to the Procurement Package 11 • Nuclear Safety & Regulatory Activities • Issues to consider on ITER nuclear safety • Proposed safety approach • Conclusion

2. 1 Personal info Miguel DAPENA FEBRER • 25 years-old • Spanish • Engineering degree at ETSEIB-UPC, Barcelona • Specialization on Nuclear Engineering • European Master of Science in Nuclear Engineering by ENEN • Working at FEEL-UPC EFDA Goal Oriented Training Program • 3 years training program • Training on specific fusion subjects at a host Association GOTP - Port Plug Engineering • CEA, FZK, FZJ, HAS Consortium for Port Plug Engineering • Where am I ? • Start date: January 2009 • Training supervisor: Sophie SALASCA • Subjects: Nuclear Safety, Neutronics, Nuclear Engineering for PPE

3. 2 Introduction to the PP11 What is a Port PlugAssembly • Equatorial Port Plug • Port Interspace • Port Cell Basic functions • Provide n,gshielding • Support BSM • Close VV ports providing 1st confinement barrier • Support and allocate diagnostics components & systems

4. 2 Introduction to the PP11 Which are the duties bound to PP11? • Design Port Plug Structure • Design Vis/IR diagnostic (CEA) • Allocate & integrate all other diagnostics ITER = INB Subject to the same strict norms as a regular fission plant • Manufacture & installation • Testing • Altogether QA • License • Others…

5. 3 Nuclear Safety & Regulatory Activities So, what does it mean that something has to be « licensed » ? • Licensing means that a part or the whole design is well demonstrated to be compliant with the rules and achieve the objectives imposed by a Regulatory Commission (ASN). But what kind of rules are those asked by the Regulatory Commission ? • Ultimate Safety Objective: “To protect people and the environment from harmful effects of ionizing radiation” • Technical Safety Objective: “To take all reasonably practicable measures to prevent accidents in nuclear installations and to mitigate their consequences,which could harm people or the environment”

6. 3 Nuclear Safety & Regulatory Activities How a design is assessed to be compliant with all those safety objectives and rules ? • Identify sources of radiation, toxicity, stored energy… that could threaten the safety objectives High Level Waste from a Nuclear Power Plant • Identify all systems provided in the design to guarantee safety Confinement Cooling • Identify all Postulated Initiating Events (PIE) that could lead to a sequence in which sources would threat safety objectives, even if its occurrence probability is very low Leak in confinement Sabotage in conf. Aircraft crash … Loss of Cooling Flow (pump break, pipe break, loss of electricity) Loss of heat exchange Out of expected range (DNB) As Low As Reasonably Achievable Defense in Depth • Guarantee that systems are capable to • Prevent the occurrence accidents • Mitigate the consequences of those accidents which safety systems are not capable to prevent Redundant, Independent and Diverse Safety Systems… Corium sinks, hydrogen recombiners/combustors,… • To be sure that there is an emergency plan in case all workers and near towns could be evacuated in case all previous measures fail Iodine pills, periodic emergency exercises, ready fleet of buses

7. (1999) TOKAIMURA Japan (1979) TMI USA 3 Nuclear Safety & Regulatory Activities But, ITER is an fusion experiment, and its amount of radioactivity will be several orders of magnitude below a regular fission plan !! • Regulatory Commission objectives & rules must be achieved no matter in what nuclear or radioactive installation • Historically, not to perform thorough and continuous safety assessments or neglecting (international) nuclear safety rules has led to commit terrible risks or even terrible accidents • Unexpected events • Everything has to be procedure • Operator have to be thoroughly trained, even every several years

8. 3 Nuclear Safety & Regulatory Activities

9. 4 Issues to consider So, what’s the problem? Why do we need a different safety approach for ITER? • There is no completed design of Port Plug Systems or Diagnostics yet • No final set of sources, PIEs, Safety System configuration, etc • Unknown design of other diagnostics  threating any Safety System? • Regulatory Commission never licensed a fusion machine before • Huge amount of new (and unproven) technologies reliability? Failure frequency? • Which could be the effect of a strong magnetic ? • How will be the embrittlement process on materials? • New field of reactor physics, kinematics & principle • Life-cycle process unknown

10. DESCENDING DESIGN Method System engineering Method Functional requirements System requirements Component requirements Functional design Abstraction level Systems design Components design 5 Proposed Safety Approach Objectives, Principles « So, do we need to stand sat until a final regulatory approach/design is established? » Requirements Guidelines Design Bear in mind that every stage should be as independent as possible on that one beneath

11. 5 Proposed Safety Approach « DESCENDING DESIGN » Method Objectives: • Customer needs & expectations towards the project • As simple & clear as possible • Have to be enough & complete so that success can be achieved if those objectives are met Objectives, Principles Objectives, Principles Provide vacuum isolation between in-vessel and ex-vessel space • Present necessaryattributes, capabilities, qualities • Feasible, Mandatory, Consistent, Observable • They can be “purified” until having a requirement addressing to a unique need Requirements: Requirements Requirements SHALLs Confinement barriers shall guarantee a leakrate lower than 10-7 Pa.m3s-1 Guidelines Guidelines • Compilation of know-how, good practices and recommendations to proceed with a design that meets the requirements • Usually presented as a list of tasks and activities Guidelines: SHOULDs Vacuum Class materials and specific QA for those materials and parts should be used Descending Pressure cascade should be provided In-Operation leak test should be provided … Design

12. 5 Proposed Safety Approach Work Plan proposal • Gather needs from all stakeholders Objectives, Principles Objectives, Principles • ITER / F4E • IAEA / ASN • etc • Are needs towards the PP11 clear enough? • Define our objectives according to what has been said before …necessary and sufficient conditions to achieve success.. Requirements Requirements 3. Extract “imposed” requirements from stakeholders’ needs SAFETY 4. Requirements/functional analyses System engineering Guidelines Guidelines 5. Guides, Handbooks, manuals, know-how compilation 6. Design synthesis Design

13. 6 Conclusion • ITER will be a Nuclear Installation needing to be licensed, as well as all its components • There are still many uncertainties to perform safety assessments • Safety assessments could use an scalable approach (Descending Design/System Engineering)to be applied since early stages of design Objective: • Establishment of (preliminary) safety requirements for PP11 • Stage at ITER Organization in the Safety Design and Integration Section •  Gather ITER needs in relation with PP11 • Stage at ENEA to be taught on MCNP calculations for Equatorial Port Plug •  Neutronic assessments for PP11 Immediate steps:

14. Thank you for your attention