Pool Test Reactor was a 10 kWt light water moderated pool-type reactor fueled with highly enriched uranium

Enriched uranium

Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...

 built at Chalk River

Chalk River

Chalk River is a Canadian rural community part of the Laurentian Hills municipality in Renfrew County, Ontario. It is located in the Upper Ottawa Valley along Highway 17 , 10 km inland from the Ottawa River, approximately 21 km northwest of Petawawa, and 182 km northwest of Ottawa...

 in 1957. It used 93% enriched uranium-aluminum plate-type fuel. The reactor, was used for burnup measurement of fissile

Fissile

In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. By definition, fissile materials can sustain a chain reaction with neutrons of any energy. The predominant neutron energy may be typified by either slow neutrons or fast neutrons...

 samples from NRX

NRX

NRX was a heavy water moderated, light water cooled, nuclear research reactor at the Canadian Chalk River Laboratories, which came into operation in 1947 at a design power rating of 10 MW , increasing to 42 MW by 1954...

. The reactor was designed and built by Canadair

Canadair

Canadair Ltd. was a civil and military aircraft manufacturer in Canada. It was a subsidiary of other aircraft manufacturers, then a nationalized corporation until privatized in 1986, and became the core of Bombardier Aerospace....

, now a division of Bombardier

Bombardier Aerospace

Bombardier Aerospace is a division of Bombardier Inc. and is the third-largest airplane manufacturer in the world. It is headquartered in Dorval, Quebec, Canada.- History :...

.

History

On Nov 29 1957 reactor attained first criticality at 12:05 pm.and shortly took over the function of ZEEP

ZEEP

The ZEEP reactor was a nuclear reactor built at the Chalk River Laboratories near Chalk River, Ontario, Canada . ZEEP first went critical at 3:45 PM, September 5, 1945...

 for measuring reactivity effects of materials, particularly after irradiation

Irradiation

Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve a specific purpose, rather than radiation exposure to...

. It was shut down and defueled in 1990.