On PP11 Safety Approach

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On PP11 Safety Approach

• Requirement 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

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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

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2 Introduction to the PP11
What is a Port Plug Assembly

• Equatorial Port Plug

• Port Interspace

• Port Cell

• Basic functions
• Provide n,g shielding
• Support BSM
• Close VV ports providing 1st confinement barrier
• Support and allocate diagnostics components
  systems

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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

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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 Activities
How 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

High Level Waste from a Nuclear Power Plant

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

Confinement
Cooling

1. 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,

1. 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
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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

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3 Nuclear Safety Regulatory Activities
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4 Issues to consider
So, whats 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

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5 Proposed Safety Approach

•  So, do we need to stand sat until a final
  regulatory approach/design is established? 

Objectives, Principles
Requirements
Guidelines
Design
Bear in mind that every stage should be as
independent as possible on that one beneath
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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
Requirements

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

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
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5 Proposed Safety Approach

• Work Plan proposal

1. Gather needs from all stakeholders

Objectives, Principles
Objectives, Principles

• ITER / F4E
• IAEA / ASN
• etc
• Are needs towards the PP11 clear enough?

1. 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
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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

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
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• Thank you for your attention