Boiling water reactor

The boiling water reactor (BWR) is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor (PWR), also a type of light water nuclear reactor. The main difference between a BWR and PWR is that in a BWR, the reactor core heats water, which turns to steam and then drives a steam turbine. In a PWR, the reactor core heats water, which does not boil. This hot water then exchanges heat with a lower pressure water system, which turns to steam and drives the turbine. The BWR was developed by the Idaho National Laboratory and General Electric (GE) in the mid-1950s. The main present manufacturer is GE Hitachi Nuclear Energy, which specializes in the design and construction of this type of reactor.

Overview

The boiling water reactor (BWR) uses demineralized water as a coolant and neutron moderator. Heat is produced by nuclear fission in the reactor core, and this causes the cooling water to boil, producing steam. The steam is directly used to drive a turbine, after which it is cooled in a condenser and converted back to liquid water. This water is then returned to the reactor core, completing the loop. The cooling water is maintained at about 75 atm (7.6 MPa, 1000–1100 psi) so that it boils in the core at about 285 °C (550 °F). In comparison, there is no significant boiling allowed in a PWR (Pressurized Water Reactor) because of the high pressure maintained in its primary loop—approximately 158 atm (16 MPa, 2300 psi). The core damage frequency of the reactor was estimated to be between 10⁻⁴ and 10⁻⁷ (i.e., one core damage accident per every 10,000 to 10,000,000 reactor years).

BMP-1

The BMP-1 is a Soviet amphibious tracked infantry fighting vehicle. BMP stands for Boyevaya Mashina Pekhoty 1 (Russian: Боевая Машина Пехоты 1; БМП-1), meaning "infantry fighting vehicle". The BMP-1 was the first mass-produced infantry fighting vehicle (IFV) of USSR. It was called the M-1967, BMP and BMP-76PB by NATO before its correct designation was known.

The Soviet military leadership saw any future wars as being conducted with nuclear, chemical and biological weapons and a new design combining the properties of an armored personnel carrier (APC) and a light tank like the BMP would allow infantry to operate from the relative safety of its armoured, radiation-shielded interior in contaminated areas and to fight alongside it in uncontaminated areas. It would increase infantry squad mobility, provide fire support to them, and also be able to fight alongside main battle tanks.

The BMP-1 was first tested in combat in the 1973 Yom Kippur War, where it was used by Egyptian and Syrian forces. Based on lessons learned from this conflict, and early experiences in the Soviet War in Afghanistan, a version with improved fighting qualities was developed, called the BMP-2. It was accepted into service in August 1980.