physics

PLUTO reactor

PLUTO reactor is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PLUTO reactor rather than just read about it. In short: PLUTO was a materials testing nuclear reactor housed at the Atomic Energy Research Establishment, a former Royal Air Force airfield at Harwell, Oxfordshire in the United Kingdom. Background PLUTO was one of five reactors on the site.

Key takeaways

PLUTO reactor belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PLUTO reactor to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PLUTO reactor from memory before moving on to harder problems.

Reference excerpt

PLUTO was a materials testing nuclear reactor housed at the Atomic Energy Research Establishment, a former Royal Air Force airfield at Harwell, Oxfordshire in the United Kingdom.

Background PLUTO was one of five reactors on the site. The site was selected as the scientific center for research and development of UK's expanding nuclear programs. Designed by the United Kingdom Atomic Energy Authority (UKAEA), the reactor was built by Head Wrightson Processes Ltd, an industrial firm in Teesside, England. PLUTO was one of two high flux reactors; the first, DIDO, was its prototype. PLUTO was the second of three DIDO class reactors in the UK to become operational. PLUTO and DIDO were located at Harwell; the third, Dounreay (DMTR) was built in Caithness, Scotland. The development of multi-purpose type PLUTO reactors gave rise to many countries building their own materials testing reactors based on DIDO's design. On 27 October 1957, the PLUTO reactor was commissioned and operated for thirty three years before decommissioning in 1990.

Design PLUTO was based on the design of DIDO and used enriched uranium metal fuel, and heavy water as both neutron moderator and primary coolant. The core was a cylinder with a diameter of 87.5 centimetres (34.4 in) and a height of approximately 61 centimetres (24 in). The radioactive shielding consisted of 0.65 centimetres (0.26 in) boron, 10.2 centimetres (4.0 in) lead, 45 centimetres (18 in) of iron shot concrete, and 120 centimetres (47 in) of barytes concrete. There was a graphite neutron reflector surrounding the core. The fuel element was an eighty-per cent enriched uranium, U-235, alloyed with aluminum plates. The PLUTO reactor started operating at 10 MW thermal power but increased during upgrades to 25 MW during its operation.

Tests Performed The multipurpose PLUTO reactor had many diverse functions; testing materials for commercial reactors to investigating crystal structures. Its main functions were fuel production, materials testing and sample activation experiments which involved testing the effects of graphite behavior under irradiation. Materials testing at the Harwell site involved irradiating materials using the reactors. This happened in one of 3 locations, a Mark V hollow fuel element in the Pluto reactor, a flux position in DIDO, and the flux converter in PLUTO. The aim of the flux converter was to give the materials the spectrum of low spatial variation of neutron and gamma fluxes seen by a light-water reactor rather than the heavy-water reactor, PLUTO. An experiment performed to test the effects of graphite behavior under irradiation revealed the effects of irradiation for 20–30 years in a civil reactor from materials tested in these reactors during the course of a few months. Other activities and experiments carried out were:physics research such as neutron scattering, chemistry studies, and radioisotopes production used in medical facilities and other industries. Because the twin reactors, PLUTO and DIDO, worked on a continuous basis rotating in and out of operation, there was continued flow of short-lived radioisotopes for hospitals. The radioisotopes generated account for 70% of the UK radioisotopes sold on the international markets.

Decommissioning PLUTO reactor went critical in 1957 and reached its end of life in 1990. It is expected to be completely dismantled by 2024. Decommissioning is carried out in three stages, as defined by the International Atomic Energy Agency (IAEA) Standards. It began with the shutdown of the reactor following closure of nuclear plant. The first stage was removing radioactive materials and operational waste. Second stage involved dismantling active and non-active plants but keeping building structure and the reactor shield intact. Stage three involved demolishing building structures, dismantling the reactor core and bio shield, and site cleanup of all radioactive waste to restore site for other purposes. By 1994 and 1995, PLUTO was at stage two decommissioning

Worked examples

Example 1 — a first encounter with PLUTO reactor

Start with the simplest possible case. Write down what PLUTO reactor claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PLUTO reactor before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PLUTO reactor ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PLUTO reactor

In research: PLUTO reactor appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses PLUTO reactor in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: PLUTO reactor is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1957 establishments in the United Kingdom, 1990 disestablishments in the United Kingdom, Buildings and structures in Oxfordshire, so understanding it makes those chapters shorter.
In everyday life: Look for PLUTO reactor outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study PLUTO reactor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PLUTO reactor means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain PLUTO reactor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PLUTO reactor in simple terms?

PLUTO was a materials testing nuclear reactor housed at the Atomic Energy Research Establishment, a former Royal Air Force airfield at Harwell, Oxfordshire in the United Kingdom. Background PLUTO was one of five reactors on the site.

Why does PLUTO reactor matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PLUTO reactor?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PLUTO reactor.