Evolution of ACR Physics from CANDU 6.

36 Pages·2003·1.13 MB·English

Evolution of ACR Physics from CANDU 6
By Peter Chan, ACR Fuel & Physics Section Head
Presented to US Nuclear Regulatory Commission
Office of Nuclear Reactor Regulation
December 4, 5, 2002 at CRL
Outline
(cid:1)
Major differences between ACR and CANDU 6 Core
Designs
(cid:1)
Coolant
(cid:1)
Fuel
(cid:1)
Lattice Pitch
(cid:1)
Core Physics of ACR
(cid:1)
High Power Output in a Compact Core
(cid:1)
Negative Power Feedback Reactivity Coefficients
(cid:1)
Negative Coolant Void Reactivity
(cid:1)
Unique LOCA features
(cid:1)
Summary
Pg 2
Major Differences between
CANDU 6 and ACR
(cid:1)
Coolant
(cid:2)
CANDU 6 (D O )
2
(cid:2)
ACR (H O)
2
(cid:1)
Fuel
(cid:2)
CANDU 6 (NU in 37-element bundle)
(cid:2)
ACR (2.0 % SEU in 42 pins, Central Pin Dy/NU, CANFLEX
bundle)
(cid:1)
Lattice Pitch
(cid:2)
CANDU 6 (28.575 cm, 11.25 inches)
(cid:2)
ACR (22.0 cm, 8.66 inches)
Pg 3
Comparison of CANDU 6 and ACR Lattices
CANDU 6 Lattice
ACR Lattice
Pg 4
Core Size Comparison
CANDU 6
728 MWe
380 channels
Diameter = 760 cm
( 299 inches)
ACR
731 MWe
284 channels
Diameter = 520 cm
( 205 inches)
Calandria volume reduced
by a factor of 2.5 (smaller
lattice pitch).
By using H O coolant, less
2
than 25% of D O used in C6
2
is required.
Pg 5
Reactivity Effects in ACR-700 and CANDU 6
(Equilibrium Core)
ACR-700 CANDU-6
(cid:1)
Moderator Temperature -0.013 (mk/ F ) slightly positive
(including density) effect
(cid:1)
Coolant Temperature -0.006 (mk/ F ) positive
(including density) effect
(cid:1)
Fuel Temperature effect -0.008 (mk/ F) small negative
Power Coefficient (95% - -0.07 mk/% power ~ 0
105% full power)
Full-Core Coolant-Void -3.0 mk +10 to +15 mk
Reactivity
Pg 6
Safety & Control Parameters in ACR-700 and CANDU 6
ACR-700 CANDU 6
Total Delayed Neutron 0.0056 0.0058
Fraction ( ß )
Prompt Neutron Lifetime 0.33 0.92
( millisecond)
Bulk & Spatial Control 18 Controllers in 14 Controllers in
9 Assemblies 7 Assemblies
Fast Power Reduction 4 Mechanical 4 Mechanical
Absorber Rods
Absorber rods
Shutdown System (SDS1) 20 Absorber 28 Absorber
Rods
Rods
Shutdown System (SDS2) 6 Poison Nozzles 6 Poison Nozzles
(reflector region) (core region)
Pg 7
Effect of Prompt Neutron Lifetime on Power Transients
4.0
l*=0.33 ms +1 mk Step
l*=0.90 ms +1 mk Step
3.5 l*=0.33 ms +3 mk Step
l*=0.90 ms +3 mk Step
l*=0.33 ms +0.5 mk Step
3.0 l*=0.90 ms +0.5 mk Step
l*=0.33 ms -3.0 mk Step
l*=0.90 ms -3.0 mk Step
2.5
r
e
w
o
P
e 2.0
v
ti
a
el
R
1.5
1.0
0.5
0.0
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Time (second)
Pg 8
Characteristics of ACR-700 and CANDU 6
ACR-700 CANDU 6
Fuel Channels 284 380
Reactor Thermal 1982 2064
Power ( MW)
Gross Electrical 731 728
Power ( MW)
Fuel Enrichment 2.0% in 42 pins 37 NU pins
Central NU/Dy pin
Core-Averaged 20.5 7.5
Burnup (MWd/kgU)
Fueling Rate 5.8 16
(Bundles per Day)
Channel Visits/Day 3 2
Pg 9
CANDU Fuel Bundle Designs
Dy
3377--EElleemmeenntt BBuunnddllee CCAANNFFLLEEXX
CC66 FFuueell CChhaannnneell BBuunnddllee ((4433 eelleemmeennttss))
AACCRR FFuueell CChhaannnneell
Pg 10