Page 171 - Dynamics and Control of Nuclear Reactors

168 CHAPTER 13 Boiling water reactors

13.2.2 BWR-2
BWR-2 produces greater power levels (greater than 500 MWe) than BWR-1. It uses
mechanical recirculation pumps and Mark I containment (See below). BWR-2 and
four subsequent designs (BWR-3 through BWR-6)) are all considered to be Gener-
ation II reactors.

13.2.3 BWR-3
BWR-3 produces greater power levels (800 MWe) than BWR-2 and was the first
BWR to use jet pumps for recirculation flow. It uses Mark I containment.

13.2.4 BWR-4
BWR-4 is similar to BWR-3, but it operates at higher power (1100 MWe). BWR-4
reactors use either Mark I or Mark II containment.

13.2.5 BWR-5
BWR-5 is similar to BWR-4. It operates at the same power level as BWR-4 power
(1100 MWe). BWR-5 reactors use either Mark I or Mark II containment.

13.2.6 BWR-6
BWR- 6 is available in different configurations having power levels of 600–
1400MWe. BWR-6 uses Mark III containment.

13.2.7 ABWR

ABWR is a Generation III reactor. The ABWR employs internal mechanical recir-
culation pumps. It uses Mark III containment and the power level is 1500 MWe.

13.3 Characteristics of BWRs
13.3.1 General features of a BWR
Since there are five different Generation II BWRs, it is necessary to pick one for pro-
viding an overview of BWR characteristics. BWR-6 was chosen, but its dynamic
behavior and control strategy is typical of all Generation II BWRs. The main differ-
ence is that it operates at a higher power level than earlier designs. Fig. 13.1 shows a
typical BWR-6 system.
Fig. 13.2 shows a BWR-6 reactor vessel and internals [1].
Subcooled water enters the bottom of the core. The flow rate and pressure are
such that boiling begins near the entrance. Boiling continues along the rest of the
passage through the core. A steam-water mixture exits the core region. This mixture