IN REACTOR PHYSICS ANALYSIS

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BARILOCHE, ARGENTINA

HUMAN RESOURCES TRAINING AND QUALIFICATION

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Contents

• Introduction

• Design Methodology

• Calculation Line & Uncertainties

• User Dependencies

C

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i

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Introduction

INVAP designs and builds research reactors with very demanding requirements.

Each new reactor needs increasingly detailed analysis Each new reactor needs increasingly detailed analysis.

Better prediction capabilities are needed to reduce the design Better prediction capabilities are needed to reduce the design margins due to the numerical and engineering uncertainties. This detailed analysis must be performed with a consistent level of detail from all the engineering variables.

The

The analystsanalysts playplay keykey rolerole inin thethe developmentdevelopment ofof accurateaccurate models,

models, whichwhich areare usedused toto simulatesimulate thethe systemsystem.. models,

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Flux/Production Levels Perturbation

Introduction

Flux/Production Levels

Facilities with minimum values

Perturbation

Operation

Facilities with a flux range

Spectra Target movement O i l Spectra Cold Neutrons Operational Requirements Thermal neutrons Hot Neutrons Fixed Cycle Minimum Burnup Fast Neutrons p Xe Build-Up. (Restart Capability) Flux Homogeneity Within a facility Beams Transport Reactor Pool W c y e c o oo

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Introduction

The variables needed in reactor physics analysis depend on the interaction of the neutron with the matter.

• The properties of the matter: XS and eng. data. • Eng. data depends on operational conditions.Eng. data depends on operational conditions.

• XS depends on eng. data: crystal and molecular structure of the materials, temperature, etc.

• The neutron distribution is solved with different methods & tools.

•• ModelsModels describingdescribing thethe systemsystem toto bebe analyzedanalyzed hashas approximations

approximations andand theythey areare defineddefined withwith aa givengiven useruser oror approximations

approximations andand theythey areare defineddefined withwith aa givengiven useruser oror analyst

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Design Methodology

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Design Methodology

Safety

as

Priority

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Design Methodology

Custom

Designed

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Design Methodology

Q lifi d

Qualified

Methods,

Tools &

Procedures

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Design Methodology

Well Trained

Nuclear

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Design Methodology

Reactor

Models

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Calculation Line

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Calculation Line

New innovative methods improve the analysis of the calculated

systems systems.

Un-experienced user:

• Ventures in the design of a new model design.

• Performs calculations without a solid understanding of the system under calculation

system under calculation.

• Makes very detailed geometrical model without the properMakes very detailed geometrical model without the proper temperatures information or without the impurities of the materials.

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Calculation Line

ESINLM NJOY ENDF CONDOR CONDOR XS Library OUTPUT ARCANE PARCS HXS ARCANE G O Eng. Data Cell Data Core Data NDDUMP HGEO HGEO MCNP INVAP CODE INVAP Utility CITVAP PUMA Code

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Calculation Uncertainties

Nuclear data: The nuclear data is continuously improved by the international community (ENDF/B, JENDL, JEFF, etc).

We still have high level of uncertainties of 500 pcm We still have high level of uncertainties of ~500 pcm.

Engineering data: No practical way to eliminate the eng. data

Engineering data: No practical way to eliminate the eng. data uncertainties. Tolerances need to be in agreement with the design uncertainties.

This is an important parameter to be evaluated in order to achieve a solid understanding of the reactor design

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Calculation Uncertainties

Calculation Codes: The validation of the codes is a continuous process and it is normally carried out by the code developer and the users

developer and the users.

It is good practice to use the design calculation tools in a wide It is good practice to use the design calculation tools in a wide range of different reactor designs to acquire confidence in the calculated parameter.

Calculation

Calculation Models

Models::

The

The accuracy

accuracy of

of the

the models

models

depends

depends on

on the

the specific

specific analyst,

analyst, and

and currently

currently the

the

only

only way

way to

to measure

measure his/her

his/her capability

capability to

to model

model

different

different systems

systems with

with acceptable

acceptable level

level of

of accuracy

accuracy is

is

his/her

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U

User

Dependencies

p

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Principles

(http://homer.ornl.gov/sesa/corporatesafety/hpc/principles.html)

People are fallible, and even the best make mistakes.

Error likely situations are predictable manageable and Error-likely situations are predictable, manageable, and preventable.

Individual behavior is influenced by organizational processes and values.

People achieve high levels of performance based largely on the encouragement and reinforcement received from leaders the encouragement and reinforcement received from leaders, peers, and subordinates.

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Mitigating user dependency

Specific practices & procedures to verify the proper utilization of the tools.

• Training to become familiar with the computational tools.

• Will to cross-check between analyst’s works, formally and informallyy

• Every model developed will serve a future purpose and will

b i d b th l t

be reviewed by another analyst.

• Inquisitive attitude to pursue small differences or issues AnyInquisitive attitude to pursue small differences or issues. Any unexpected difference observed between models or results when using different tools are clearly understood.

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Training

• Formal acquisition of the knowledge: universities, internal training courses, or international training courses.

S lf t i i t l f hi /h i i iti • Self-training: as a natural response of his/her inquisitive

nature.

• Teaching:Teaching: internal training courses assistant or professorsinternal training courses, assistant or professors. • Technical advisors: In thesis (Engineering, Magister and

PhD degree).g )

• Become familiar with the computational tools

( biliti d li it ti ) (capabilities and limitations):

• Performing calculation of different reactors. NPP, RR • Using different methods:Using different methods: Different computational toolsDifferent computational tools.

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Review Process

Different procedures for different review process:

Documentation: Any parameter are properly documented in a report

• Documentation: Any parameter are properly documented in a report,

which is issued by the analysts and reviewed at least by the reactor physics project leader.

physics project leader.

• Model preparation: The input, auxiliary and output files are stored in

a folder together with its table of contents explaining the purpose of each file. In complex or more sensitive models, these files are reviewed by another analyst that verifies the proper modeling of the system

another analyst that verifies the proper modeling of the system.

• Specific design parameters:Specific design parameters: In complex reactor designs, thereIn complex reactor designs, there

are additional levels of verification in an integrated view with the rest of the project.

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Document Review Process

Issued: Responsible for the veracity, accuracy, and

significance, as to the resulting effects, of all information contained and transmitted in the document

contained and transmitted in the document.

Reviewed: Indirectly responsible, they manifest that nothing

t t t f th d t t di t th i i

as to content of the document contradicts their experience.

Approved: Not responsible for the content of the document. Responsible for certifying that the content of a document is coherent with all other project documentation.

In interdisciplinary and complex projects the PDR

(preliminary design review) and CDR (critical design review)

meetings are used for the verification of the analysis of the

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Integration

• Integrate design, calculation and documentation information.

O t f d t b j t

• One set of databases per project: • Design Criteria:

• Safety and User Requirements. • Verification Procedures

• Verification Procedures.

• Tools (specific version of codes and libraries).

• Engineering Data (geometries, materials, operating states)

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Integration

• Reduce errors • Data,

• Facilitate the revision •• Generate knowledgeGenerate knowledge

,

• Interfaces,

C l l ti M th d l

g g

• Different user level/responsibilities • Calculation Methodology.

Share between the different analyst and

reviewers using the same set of tools, data,

procedures and documentation

Share between the different analyst and

reviewers using the same set of tools, data,

procedures and documentation

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Preparing data for review

The analyst is responsible to move the Input, Output and any auxiliary files (spreadsheets, auxiliary programs, etc) fory ( p , y p g , ) revision.

A Table Of Contents is required with the following information: • Filename.

• File type • File type.

• CRC file information (To verify the integrity of the file). • A short description of the purpose of the file.p p p

• Unneeded files are a future problem.

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Reviewing

Another analysts review the I/O files. Perform the following activities:

• Review the input files checking for proper modeling.

• Verify the objective and scope of the calculated parameters. • Verify the input (engineering) data was properly used.

• Check the output files and their agreement with the • Check the output files and their agreement with the

documented data.

• Cross check outputs with different tools (Output pos-p ( p p processor or Arcane program).

• Fill the review document with the recommendations or changes needed to be done.

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Verification Review Process

I t t t l l t d It b th diff t Level of verification Different options.

Important parameters are calculated by INVAP personnel using different

calculation lines.

It can be the same or different INVAP personnel.

Different group, normally non INVAP staff, perform calculation using the

INVAP l l ti d

Customer staff performing on the job training.

INVAP calculation codes. _{Subcontractors performing} calculations.

ARN perform independent analysis ARN perform independent analysis. Different group, normally costumer

staff, perform calculation using

Customer staff using their own calculation line.

different codes. _{Subcontractors performing totally} independent analysis.

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Conclusions

INVAP´s methodologies were developed to mitigate the analyst dependence in the development of accurate models. Basically these methodologies are divided in training and

tili ti f d f th d l ti

utilization of procedures for the model preparation.

The training is carried out not only during the formal The training is carried out not only during the formal acquisition of the knowledge (Theories and utilization of computational codes), but also promoting academic activities and certain specific attitudes based on fomenting the inquisitive nature of the personnel.

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Conclusions

The procedures used for documentation, input and output handling and calculated parameter allow to the sharing of knowledge, databases and models between the analysts of a project, or different projects, giving to the analysts a solid

d t di f th t d i

understanding of the reactor design.

The main aspects discussed in this paper can be extended to The main aspects discussed in this paper can be extended to other engineering areas of nuclear reactor design.

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Thank you for your attention

Questions?