MAGNOX NUCLEAR REACTOR

PRESENTED TO

SIR SHAHID KHALIL

PRESENTED BY

SAMEED QADRI ( 11-ME-69)

M.ALI KIANI (11-ME-198)

What are Nuclear Reactors?

Nuclear reactors are devices in which fissionable elements such as uranium, thorium, or plutonium are made to undergo a nuclear chain reaction.

Neutrons are bombarded to Uranium nuclei. It disintegrates into two smaller atoms ( Ba & Kr), releasing neutrons and binding energy . One of the neutron hits another Uranium-235 atom, thus furthur releasing neutrons and binding energy. Thus , process continous if it is not controlled. This is called chain reaction.

NUCLEAR CHAIN REACTION

COMPONENTS OF NUCLEAR REACTOR

Fuel rods ( Packets of Uranium oxide arranged in tubes to form rods )

1) Moderator

2) Control rods

3) Coolant

4) Pressure vessel

5) Steam generator

6) Containment

MAGNOX Magnox is short for Magnesium non-oxidising

It is basically an alloy mainly of magnesium with small amounts of aluminium and other metals

It is used to clad the fuel rods inside the reactor.

This material has the advantage of a low neutron capture cross-section, but has two major disadvantages:

It limits the maximum temperature, and hence the thermal efficiency, of the plant.

It reacts with water, preventing long-term storage of spent fuel under water.

MAGNOX NUCLEAR REACTOR

Magnox is an old type of nuclear power reactor which was designed in the United Kingdom, and was exported to other countries, both as a power plant ( as a power reactor ) and producer for plutonium ( as a research reactor )

Wylfa Nuclear Generating Facility contains the world's last operating Magnox reactor

SCHEMATIC DIAGRAM OF MAGNOX NUCLEAR

REACTOR

MAGNOX NUCLEAR REACTOR

These are graphite moderated reactors and use natural uranium as fuel & MAGNOX as fuel cladding.

Working pressure varies from 6.9 to 19.35 bar

MAGNOX REACTOR AND ECONOMY The first Magnox reactors at Calder Hallwere

designed principally to produce plutonium for nuclear weapons.

The production of plutonium from uranium generates a large amount of heat also , which could be used in a turbine to generate electricity.

Nuclear power generation is 25 % expensive than electricity from coal, yet economical due to production of plutonium.

OPERATIONS:

There are two nuclear fuel reprocessing plants at Sellafield

1. Advanced Gas-cooled Reactors (AGR)

2. Light Water Reactors (LWR)

This all happens in the Fuel Handling Plant. The fuel is then transferred to the Magnox Reprocessing Plant.

DERATING TO REDUCE CORROSION

In early operation it was found that there was significant oxidation of mild steel components by the high temperature carbon dioxide coolant, requiring a reduction in operating temperature and power output.

For example the Latina reactor was derated in 1969 by 24%, from 210 MWe to 160 MWe, by the reduction of operating temperature from 390 to 360 °C.

MAGNOX PLANTS

Magnox plants literally means magnox nuclear reactor.

A small 5 MW experimental reactor at Yongbyon, operated from 1986 to 1994, and restarted in 2003. Plutonium from this reactor's spent fuel has been used in the North Korea nuclear weapons program.

A 200 MW reactor at taechon, construction of which also halted in 1994.

GAS COOLED REACTOR

This is the general term for all type of carbon dioxide-cooled, graphite-moderated reactors, including the Magnox.

The Magnox was replaced in the British power station program by the Advanced gas-cooled reactor or AGR.

A key feature of the AGR was the replacement of magnox cladding to allow higher temperatures and greater thermal efficiency.

SAFETY

The Magnox reactors were considered at the time to have a considerable degree of inherent safety because of their simple design, low power density, and gas coolant.

Failure of the reactor shutdown system to rapidly shut down the reactor, or failure of natural circulation, was not considered in the design.