april 20091miguel dapena tore supra association euratom-cea on pp11 safety approach requirement...
TRANSCRIPT
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
April 2009 2Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 3Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 4Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
• 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
April 2009 5Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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”
April 2009 6Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 7Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 8Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
3 Nuclear Safety & Regulatory Activities
April 2009 9Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
• 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?
April 2009 10Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 11Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
« DESCENDING DESIGN » Method
Objectives, Objectives, PrinciplesPrinciples
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…
April 2009 12Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
Objectives, Objectives, PrinciplesPrinciples
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
April 2009 13Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
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
April 2009 14Miguel Dapena
TORE SUPRA
AssociationEuratom-CEA
Thank you for your attention