april 20091miguel dapena tore supra association euratom-cea on pp11 safety approach requirement...

April 2009 1Miguel Dapena

TORE SUPRA

AssociationEuratom-CEA

On PP11 Safety ApproachRequirement Analysis

1. Personal info

2. Introduction to the Procurement Package 11

3. Nuclear Safety & Regulatory Activities

4. Issues to consider on ITER nuclear safety

5. Proposed safety approach

6. Conclusion


TORE SUPRA


1 Personal infoMiguel 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

– 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

GOTP - Port Plug Engineering


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2 Introduction to the PP11

• Equatorial Port Plug

• Port Interspace

• Port Cell

What is a Port Plug Assembly

Basic functions– Provide n, shielding– Support BSM– Close VV ports providing 1st

confinement barrier– Support and allocate

diagnostics components & systems


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• License

2 Introduction to the PP11

• Design Port Plug Structure

• Design Vis/IR diagnostic (CEA)

• Altogether QA

Which are the duties bound to PP11?

• Allocate & integrate all other diagnostics

• Manufacture & installation• Testing

• Others…

ITER = INB Subject to the same

strict norms as a regular fission plant


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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”


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3 Nuclear Safety & Regulatory ActivitiesHow a design is assessed to be compliant with all those safety objectives and rules ?1. Identify sources of radiation, toxicity, stored

energy… that could threaten the safety objectives

2. Identify all systems provided in the design to guarantee safety

3. 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

4. Guarantee that systems are capable toa. Prevent the occurrence accidentsb. Mitigate the consequences of those

accidents which safety systems are not capable to prevent

5. 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

High Level Waste from a Nuclear Power Plant

As

Low

As

Rea

sona

bly

Ach

ieva

ble

Def

ense

in D

epth

Confinement Cooling

Leak in confinementSabotage in conf.Aircraft crash…

Loss of Cooling Flow (pump break, pipe break, loss of electricity)Loss of heat exchangeOut of expected range (DNB)

Redundant, Independent and Diverse Safety Systems…

Corium sinks, hydrogen recombiners/combustors,…

Iodine pills, periodic emergency exercises, ready fleet of buses

DSM/DRFC

Here, Louis was complaining if I don't explain what's that, it's not worth to mention it.the truth is that I go quite fast in that slide, but it's easy to understand with all the examples


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3 Nuclear Safety & Regulatory ActivitiesBut, 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

(1979) TMI USA (1999) TOKAIMURA Japan

• Everything has to be procedure

• Operator have to be thoroughly trained, even every several years

• Unexpected events


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3 Nuclear Safety & Regulatory Activities


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• 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

4 Issues to considerSo, what’s the problem? Why do we need a different safety approach for ITER?


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5 Proposed Safety Approach« So, do we need to stand sat until a final regulatory approach/design is established? »

Objectives, Objectives, PrinciplesPrinciples

Gu

idel

ines

Gu

idel

ines RequirementsRequirements

Design

Bear in mind that every stage should be as independent as possible on that one beneath

Abs

trac

tion

leve

l

DESCENDING DESIGN Method

System engineering Method

Functionaldesign

Systemsdesign

Componentsdesign

Functional requirements System

requirements Component requirements


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« DESCENDING DESIGN » Method


Gu

idel

ines

Gu

idel

ines

RequirementsRequirements

Design

5 Proposed Safety Approach

Objectives, Principles

Requirements

Gu

idel

ines

Objectives:

Requirements:

Guidelines:

• 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

• Present necessary attributes, capabilities, qualities• Feasible, Mandatory, Consistent, Observable• They can be “purified” until having a requirement addressing to a unique need

• 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

SHALLsSHALLs

SHOULDsSHOULDs

Provide vacuum isolation between in-vessel and ex-vessel space

Confinement barriers shall guarantee a leakrate lower than 10-7 Pa.m3s-1

Vacuum Class materials and specific QA for those materials and parts should be usedDescending Pressure cascade should be providedIn-Operation leak test should be provided…


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4. Requirements/functional analyses

1. Gather needs from all stakeholders• ITER / F4E• IAEA / ASN• etc

• Are needs towards the PP11 clear enough?…necessary and sufficient conditions to achieve success..

3. Extract “imposed” requirements from stakeholders’ needs

System engineering

5. Guides, Handbooks, manuals, know-how compilation

6. Design synthesis

SAFETYSAFETY


Gu

idel

ines

Gu

idel

ines

RequirementsRequirements

Design

Objectives, Principles

Requirements

Gu

idel

ines

2. Define our objectives according to what has been said before

5 Proposed Safety ApproachWork Plan proposal


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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

Immediate steps: • 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

Objective: • Establishment of (preliminary) safety requirements for PP11


TORE SUPRA


Thank you for your attention

april 20091miguel dapena tore supra association euratom-cea on pp11 safety approach requirement...

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