Reactor mission

The principal mission adopted for commercial SMRs has been the generation of electricity. All reactor coolant types address this mission. For those plants designed

Подпись: 12 Handbook of Small Modular Nuclear Reactors

Table 1.2 Reactor characteristics by coolant

Coolant

PWR1 Light water

BWR2 Light water

HTGR

Helium3 Helium4

SFR5

Sodium

Lead6

LFR

Lead-bismuth7

Power (MWt/MWe)

530/180

750/250

250/100

625/283

840/311

700/300

280/101.5

Power density (kWt/liter

core)

69

39.5

3.2

6.8

215

116

160

Specific power (kWt/kg HM)

26.8

11.6

89.7

~120

83.6

14.5

30.8

Fuel geometry

Rods

Rods

Pebbles

Prismatic graphite blocks

Rods

Rods

Rods

Fuel material/cladding

UO2/Zr-4

UO2/Zr

uo2/triso

UCO/TRISO

(U+Pu)/SS

(U+Pu)N/SS

UO2b/8

Primary system temperature inlet/outlet (°C)

295/319

190/285

250/750

325/750

360C/499C

420/540

340/490

Primary operating pressure (MPa)

14.2

6.9

7.0

6.0

0.1

0.1

0.1

Secondary operating pressure (MPa)

5.7

NA

13.3

16.7

14.7

18

6.7

Plant thermal efficiency (%)

34

33.3

42

45

37

43a

36.3

1 Pers. Comm, D. Langley (mPower) to N. Todreas (MIT), Jan 2013.

2 VK-300 — Gabaraev et al. (2004); Kuznetsov et al. (2001).

3 HTR-PM — Zhang et al. (2009); Zhang (2012).

4 SC-HTGR — AREVA (2012).

5 PRISM — Triplett et al. (2012).

6 BREST — Smirnov (2012); Glazov et al. (2007)a.

7 SVBR-100 — Toshinsky and Petrochenko (2012); MOX and N fuel options proposed13.

8 Likely EP823 or EP450.

NA — Not applicable since the BWR only has a primary system.

Numerical values of characteristics are rounded.

 

Подпись: Small modular reactors (SMRs) for producing nuclear energy: an introduction 13

Table 1.3 Reactor coolant properties of significance1

Coolant

Water2

Helium3

Sodium4

Lead4

Lead-bismuth4

(0.445Pb-0.555Bi)

PWR

BWR

Atomic weight

18

4

23

207

208

Phase change at 1 atm

Melting point (°C)

0

NA

98

327

124

Boiling point (°C)

100

-267

892

1737

1670

Density, p (kg/m3)

704.9

754.7

3.54

880

10536

10180

Specific heat, cp (J/kg K)

5739

5235

5191

1272

147

146

Heat capacity, pcp (MJ/m3 K)

4.05

3.95

0.018

1.07

1.55

1.49

Heat transfer capability

0.543

0.585

0.31

66

15

15

Thermal conductivity, к (W/m K)

3.80

1.90

0.65

18.1

2.81

2.75

Heat transfer coefficient (X10-4) h (W/m2 K)

Dynamic viscosity (X104), р (kg/ms)

0.846

0.945

4.0

2.6

20

15

Kinematic Viscosity (X107), v = р/р (m2/s)

1.20

1.26

1.13

2.95

1.91

1.47

Thermal expansion coefficient

326

250

29

11

13

(X105), a (1/°C)

Prandtl number, Pr

0.89

0.85

0.66

0.005

0.020

0.015

1 Typical reactor values.

2 Property values at PWR average and BWR inlet conditions from Todreas and Kazimi (2012).

3 Property values at 537 0C and 6 MPa from Petersen (1970).

4 Property values at 450 0C from Hejzlar et al. (2009).

 

to be deployable to remote locations, whether placed terrestrially or dispatched as barge-mounted reactors, the added co-generation capabilities for desalinization and district heating exist. Of the water-cooled SMRs the Russian PWR and BWR systems have been designed for these additional missions. Additionally, propulsion as accomplished by Russian ice-breaker vessels using the KLT-40S reactor and its planned replacement, the RITM-200 reactor, is a further reactor mission.

The helium gas-cooled reactor can operate at high enough outlet coolant temperature, 750 °C in initial designs, to provide a process heat capability. This process heat can be used directly for various industrial processes such as shale oil recovery and the production of hydrogen by relatively high-temperature thermochemical cycles. Hydrogen production from water by electrolysis can be accomplished at the lower outlet temperature of the sodium — and lead-cooled reactors, on the order of 500­550 °C, but these SMRs have not embraced this mission due to current shrinking US interest.

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