reattore nucleare di iv generazione refrigerato con piombo brest 300

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REATTORE NUCLEARE DI IV
GENERAZIONE REFRIGERATO
CON PIOMBO BREST 300: LA
SIMULAZIONE NEUTRONICA
TRAMITE IL SOFTWARE MCNPX,
I FLUSSI NEUTRONICI E LA
RISPOSTA DI UNA TIPICA SONDA
PER REATTORI VELOCI.
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Tabella 1 – Principali caratteristiche dell’impianto
nucleare BREST 300 [1]
Potenza termica
700 MW
Potenza elettrica netta
300 MW
Temperatura del refrigerante
all’ingresso del core
693 K
Temperatura del refrigerante all’uscita del core
813 K
Pressione del refrigerante
17 bar
Flusso del refrigerante attraverso il core
3.8
Caduta di pressione all’interno del circuito primario
2 bar
Numero di generatori di vapore (GV)
8
Numero di pompe primarie (assiali)
4
Potenza del singolo generatore di vapore
87.5 MW
Capacità di ciascun GV
185.7 t/h
Fluido del circuito secondario
Water - steam
TIN/TOUT per i GV
613 K / 793 K
PIN/POUT per i GV
255 bar / 245 bar
Temperatura dell’acqua all’ingresso del GV
538 K
0 $) .0 /'+.0 (0 '1)/(1 ,/( )'+0 +/+0*1
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Strutture implementate nel codice di trasporto
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Tabella 7
Composizione isotopica del combustibile fresco
>6 6 6 > 6 >
) .0 S Sezione
verticale della parte
inferiore
dell’impianto [1]
) .0 B
Sezioni orizzontali
dell’impianto, come
in figura 2 [1]
) .0 E S Barrette di combustibile per le regioni 1,2 e 3 del nocciolo
) .0 ?
Sezione di un elemento
di combustibile (FA),
misure in mm.
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>6 6 6 > 6 >
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)( +0D1**0 FTabella 10 - Composizione isotopica dell’acciaio
HCM12A [3]
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>6 6 6 > 6 >
) .0 A
Assemblaggio
assorbitore (AA)
) .0 Schema delle
strutture in-core
ed ex-core da
implementare
) .0 Sezione orizzontale
del sistema
implementato, da
MCNPX
) .0 Sezione verticale
del sistema
implementato, da
MCNPX
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) .0 B – Spettro neutronico al centro del nocciolo
Spettri neutronici
) .0 E – Spettro neutronico in corrisponenza dell’elemento di combustibile
più periferico
) .0 ? – Spettro neutronico in corrispondenza della circonferenza mediana
del down-comer
) .0 : – Errore relativo per le misure dello spettro neutronico al centro del
reattore
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1%)0 [ X:FF1-
) .0 9 – Errore relativo per le misure dello spettro neutronico nel down-comer
) .0 A – Sezione d’urto (n, ) per 207Pb [5]
Impiego di strumentazione neutronica: camera
a fissione per alte temperature.
/1 )** '+.0+/ )( $) .0 & )* ./1++/ . ''/ .1!
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(0+0 ,/1 '/(%0 ( /%1**/ ./%/++/ %0**0
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=
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$ X (<;5
E5$<;% ,!'!;
Tabella 20 - Principali caratteristiche della camera a fissione Photonis CFUE32 [4]
11.0+ .0 %) 1'1.,))/
0+1.)0*1 %) .)1'+)1(+/
0+1.)0*1 )'/*0(+1
1(')/(1 (/)(0*1
#+.0+/ '1(')D)*1
0''0 %1**/ '+.0+/ '1(')D)*1
0' %) .)1)1(+/
6)01+./
("10
("10 '+.0+/ '1(')D)*1
1/ 1. ,/**1)/(0.1 *0 ,0.),0
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0'')0 1'/'))/(1 0) .0) 00
<;
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F- C,
./( 0 AFF 0
: EF E? EF ('
!F
F C5"!
FB C"
) .0 Detector, camera a
fissione Photonis
CFUE32 [4]
1
Tabella 22 - Composizione isotopica dello strato sensibile interno alla camera a fissione Photonis CFUE32 [4]
?
Composizione isotopica [%w/w]
234
U
0.059731
235
U
98.048936
236
U
0.039821
238
U
1.403686
16
O
0.447826
Tabella 23 - Risposta della camera a fissione Photonis CFUE32 per un flusso termico [4]
Thermal neutronic
flux [n]
[n/(cm2s]
103앦108
107앦3·1012
109앦1013
Pulse mode
Campbelling mode
Current mode
Signal
10-3 conteggi/(s·n/(cm2s>)
4·10-29A2/(Hz·n/cm2)
10-16A/n(n·cm-2s-1)
Tabella 24 - Segnale in uscita dalla camera a fissione Photonis CFUE32 per il flusso neutronico tipico del BREST 300
in corrispondenza del down-comer
Neutronic flux [n]
[n/(cm2s]
103앦108
107앦3·1012
109앦1013
Pulse mode
Campbelling mode
Current mode
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Signal
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1.45·10-29A2/(Hz·n/cm2)
3.62·10-17A/n(n·cm-2s-1)
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0.) )(+1(')+3-
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