HYTHEST - A MONTE CARLO PROGRAM FOR THE EVALUATION OF THE CORRECTION FACTORS IN A BWR AND PWR CORE

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• Publié par: JOINT-RESEARCH-CENTRE
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• Langue: English
• Poids de l'ouvrage: 3 Mo

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HYTHEST ­ i MONTE CARLO PROGRAM FOR
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Euratom Contract No 035­60­11 RDI with FIAT SpA, Turin (Italy)
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giving the reference : « EUR 1587.e — HYTHEST
A MONTE CARLO PROGRAM FOR THE EVALUA­
I,1^ET?ÄRECTION PACTOESIN A BW*
This document was duplicated on the basis of the best
available copy.
Printed by L. VANMELLE S.A.. GHENT
Brussels, March 1964 EUR 1587.e
HYTHEST - A MONTE CARLO PROGRAM FOR THE
EVALUATION OF THE CORRECTION FACTORS IN A BWR
AND PWR CORE by A. BORELLA - G. DI COLA (EURATOM)
and G. POZZI (FIAT)
European Atomic Energy Community - EURATOM
EURATOM/USA Agreement for Cooperation
EURAEC Report No 987 prepared at the Joint Nuclear Research
Center — Ispra Establishment (Italy)
Euratom Contract No 035-60-11 RDI with FIAT SpA - (Italy)
Brussels, March 1964 — 79 pages — 1 figure
HYTHEST is a Monte Carlo code written in Fortran language
for the IBM 7090. With this code it is possible to study statisti­
cally the influence that the random variations of the independent
parameters subjected to fabrication tolerances (fuel density and
enrichment, geometric dimension) have on the dependent thermal
hydraulic variables (temperatures, vapour quality, pressure drop)
in a PWR and BWR reactor core.
EUR 1587.e
HYTHEST - A MONTE CARLO PROGRAM FOR THE
EVALUATION OF THE CORRECTION FACTORS IN A BWR
AND PWR CORE by A. BORELLA - G. DI COLA (EURATOM)
and G. POZZI (FIAT)
European Atomic Energy Community - EURATOM
EURATOM/USA Agreement for Cooperation
EURAEC Report No 987 prepared at the Joint Nuclear Research
Center — Ispra Establishment (Italy)
Euratom Contract No 035-60-11 RDI with FIAT SpA - (Italy)
Brussels, March 1964 — 79 pages — 1 figure
HYTHEST is a Monte Carlo code written in Fortran language
for the IBM 7090. With this code it is possible to study statisti­
cally the influence that the random variations of the independent
parameters subjected to fabrication tolerances (fuel density and
enrichment, geometric dimension) have on the dependent thermal
hydraulic variables (temperatures, vapour quality, pressure drop)
in a PWR and BWR reactor core.
EUR 1587.e
HYTHEST - A MONTE CARLO PROGRAM FOR THE
EVALUATION OF THE CORRECTION FACTORS IN A BWR
AND PWR CORE by A. BORELLA - G. DI COLA (EURATOM)
and G. POZZI (FIAT)
European Atomic Energy Community - EURATOM
EURATOM/USA Agreement for Cooperation
EURAEC Report No 987 prepared at the Joint Nuclear Research
Center — Ispra Establishment (Italy)
Euratom Contract No 035-60-11 RDI with FIAT SpA - (Italy)
Brussels, March 1964 — 79 pages — 1 figure
HYTHEST is a Monte Carlo code written in Fortran language
for the IBM 7090. With this code it is possible to study statisti­
cally the influence that the random variations of the independent
parameters subjected to fabrication tolerances (fuel density and
enrichment, geometric dimension) have on the dependent thermal
hydraulic variables (temperatures, vapour quality, pressure drop)
in a PWR and BWR reactor core. According to the « spot model », a random core is built up,
choosing in every region of the core the values of the independent
parameters with the aid of a random sampling routine.
Next with a detailed thermal hydraulic calculation routine
the values of the dependent variables are calculated in this random
sampled core.
This procedure is repeated according to a Monte Carlo technique,
choosing as many random cores as necessary.
According to the « spot model », a random core is built up,
choosing in every region of the core the values of the independent
parameters with the aid of a random sampling routine.
Next with a detailed thermal hydraulic calculation routine
the values of the dependent variables are calculated in this random
sampled core.
This procedure is repeated according to a Monte Carlo technique,
choosing as many random cores as necessary.
According to the « spot model », a random core is built up,
choosing m every region of the core the values of the independent
parameters with the aid of a random sampling routine.
Next with a detailed thermal hydraulic calculation routine
the values of the dependent variables are calculated in this random
sampled core.
This procedure is repeated according to a Monte Carlo technique,
choosing as many random cores as necessary. EUR 1587.e
EUROPEAN ATOMIC ENERGY COMMUNITY - EURATOM
HYTHEST - A MONTE CARLO PROGRAM FOR
THE EVALUATION OF THE CORRECTION
FACTORS IN A BWR AND PWR CORE
by
A. BORELLA - G. DI COLA (EURATOM) and G. POZZI (FIAT)
1964
EURATOM/USA Agreement for Cooperation
EURAEC Report No 987 prepared at the Joint Nuclear Research Center
Ispra Establishment - Italy
Euratom Contract No 035-60-11 RDI with FIAT SpA, Turin (Italy) CONTENTS
Page
INTRODUCTION
PART I Mathematical Description of the HYTHEST Code · · · 7
References 29
PART II Description of the FORTRAN Program 31
PART III Use of the Program 33
Annexed:
LISTING OF THE PROGRAM 4
SAMPLE PROBLEM 69 INTRODUCTION
A nuclear core is physically defined by a certain number of in­
dependent variables (x. ), which define core geometry and mate­
rial characteristics: for example, fuel density and enrichment,
fuel radius, cladding internal and external radius. These x,'s
variables are subjected to statistical variations from point to
point in the core.
On designing a reactor, one is faced with the problem of determi­
ning certain thermal and hydraulic dependent variables
X — Ι ^Λ p · m · f X. f · 9 β o J
To solve this problem, an approximate model has been introduced.
( 3t )
In this model, called "spot model"v ' each fuel channel of the
reactor core is considered as subdivided in small regions (spots):
in each of these small regions the x.'s are assumed constant and
their actual values are chosen at random (independently one from
the other, and in an independent way from region to region) accor­
ding to their experimental distribution curves due to fabrication
tolerances »
Having represented in this way an "actual" core it is possible,
with the aid of a detailed thermal and hydraulic calculation rou­
tine, to evaluate all the interesting Y variables relative to such
a core. This procedure is repeated according to a Monte Carlo
technique, choosing at random as many "random cores" as necessary,
In this way actual probability and distribution curves for the Y
variables can be constructed.
ve
A digital code has been deàoped using the IBM 709O computer of
Euratom­C.E.T.I.S. Group at Ispra. This code with the aid of a
random sampling technique performs the construction of the random
sampled cores. For each chosen reactor a detailed thermal hydrau­
lic calculation is done anu finally the thermal hydraulic popula­
tions so obtained are statistically analysed.
(x) see reference 2.