Transcript Document

Association
Euratom-CEA
TORE SUPRA
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
April 2009
Miguel Dapena
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Association
Euratom-CEA
TORE SUPRA
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
April 2009
Miguel Dapena
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Association
Euratom-CEA
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TORE SUPRA
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
April 2009
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Association
Euratom-CEA
2
TORE SUPRA
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
• Manufacture & installation
Subject to the same
• Testing
strict norms as a
regular fission plant
• Altogether QA
• License
• Others…
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Association
Euratom-CEA
TORE SUPRA
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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Association
Euratom-CEA
TORE SUPRA
3 Nuclear Safety & Regulatory Activities
How a design is assessed to be compliant with all those safety
objectives and rules ?
3.
4.
5.
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
Guarantee that systems are capable to
a. Prevent the occurrence accidents
b. Mitigate the consequences of those
accidents which safety systems are not
capable to prevent
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
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High Level Waste from a Nuclear
Power Plant
As Low As Reasonably Achievable
2.
Identify sources of radiation, toxicity, stored
energy… that could threaten the safety
objectives
Identify all systems provided in the design to
guarantee safety
Defense in Depth
1.
Miguel Dapena
Confinement
Leak in confinement
Sabotage in conf.
Aircraft crash
…
Cooling
Loss of Cooling Flow
(pump break, pipe break, loss of
electricity)
Loss of heat exchange
Out of expected range (DNB)
Redundant, Independent and Diverse Safety Systems…
Corium sinks, hydrogen recombiners/combustors,…
Iodine pills, periodic emergency exercises, ready fleet of
buses
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Association
Euratom-CEA
TORE SUPRA
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
• Everything has to
be procedure
• Unexpected
events
• Operator have to
be thoroughly
trained, even every
several years
(1979) TMI USA
April 2009
(1999) TOKAIMURA Japan
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Association
Euratom-CEA
TORE SUPRA
3 Nuclear Safety & Regulatory Activities
April 2009
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Euratom-CEA
TORE SUPRA
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


•
Unknown design of other diagnostics  threating any Safety System?
Regulatory Commission never licensed a fusion machine before


•
No final set of sources, PIEs, Safety System configuration, etc
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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Euratom-CEA
TORE SUPRA
5 Proposed Safety Approach
« So, do we need to stand
sat until a final regulatory
approach/design is
established? »
requirements
Component
requirements
Requirements
Abstraction level
System
Objectives,
Principles
System engineering
Method
Guidelines
Functional
requirements
DESCENDING
DESIGN Method
Design
Functional
design
Systems
design
Bear in mind that
every stage should be
as independent as
possible on that one
beneath
Components
design
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Association
Euratom-CEA
TORE SUPRA
5 Proposed Safety Approach
« DESCENDING DESIGN » Method
Objectives: • Customer needs & expectations towards the project
Objectives,
Principles
• As simple & clear as possible
• Have to be enough & complete so that success can
be achieved if those objectives are met
Provide vacuum isolation between in-vessel and ex-vessel space
Requirements: • Present necessary attributes, capabilities, qualities
Guidelines
Requirements
SHALLs
• Feasible, Mandatory, Consistent, Observable
• They can be “purified” until having a requirement
addressing to a unique need
Confinement barriers shall guarantee a leakrate lower than 10-7 Pa.m3s-1
Guidelines:
SHOULDs
Design
April 2009
• 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
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
…
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TORE SUPRA
5 Proposed Safety Approach
Work Plan proposal
Objectives,
Principles
1. Gather needs from all stakeholders
• ITER / F4E
IAEA
/ ASN
2. Define •our
objectives
according to what has been
• etc
said before
…necessary and sufficient conditions to achieve success..
• Are needs towards the PP11 clear enough?
Guidelines
Requirements
3. Extract “imposed” requirements from
stakeholders’ needs
SAFETY
4. Requirements/functional analyses
System engineering
5. Guides, Handbooks, manuals, know-how
compilation
Design
April 2009
6. Design synthesis
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Euratom-CEA
TORE SUPRA
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
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
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Association
Euratom-CEA
TORE SUPRA
Thank you for your attention
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