The Nuclear Industry

Introduction

There is considerable speculation and heated discussions on what the national power supply should be, as the options include wind and solar, gas including hydrogen, pumped hydro, nuclear, and several others under development. One of the possibilities is the nuclear one, and as it is almost unknown in Australia the features and potential are discussed and argued without any real knowledge or understanding. This essay aims to provide a reasonable understanding of the nuclear technology, without promoting or dismissing it as a possibility for Australia.

There are several different groups of reactors in current use or design. One group is based on “size “and the second group is based on technical design. The three sizes are Standard, Small Modular Reactors [SMR] and Micro Reactors.

The Standard are those which are custom designed, and custom built for a specific location and application, and the current reactors are of this type. They are large, in excess of 300 MW[e], and have an average operating life span of at least 40 years. The actual construction time is 6 years, and the decommissioning time can be in excess of 25 years and the government approval process can take several years. These are expensive and have been in place for many decades.

The Small Modular Reactor [SMR] is physically much smaller than the standard models, have a capacity of less than 300 MW[e] they can be constructed remotely and installed at the desired location. There are only 2 presently in the grid, but there is considerable interest in them as they present a “standardised” product which can be used singly or in groups. These are predicted to be of significant future interest.

And Micro Reactors, there are none in the grid and none are expected.

Technical Background

There are at least 6 different types of nuclear generation all of which tend to fit be either pressurised water reactors or boiling water reactors. The basic action of nuclear reactors is to heat water to produce steam, and that steam operates a generator.

There are 407 reactors currently in use in 38 countries. There are 58 under
construction and 22 have completed the decommissioning phase, and the average operating age is 40 which means they are reaching the end of their operating life span and therefore a replacement plan is required.

Reasons for the reluctance of nuclear

There is apprehension about nuclear, and the reasons may include; the Costs which seem to be escalating for both the construction and the operation; Historically it takes 6 years to build a facility, and that is after the bureaucratic approval process, and Govt intervention of which there are 2 aspects. The first is that global governments are investing in industry. The other issue is the government intervention may be very slow in providing approvals, and the actual requirements are often excessive.

It is unfortunate that the public perception is a negative one, relating to safety concerns, as a consequence of the publicity associated with the three accidents

The three accidents

Three accidents which are often quoted are Three Mile Island, Chernobyl and the Fukushima Accidents. The three events gained worldwide negative publicity and have been touted as reasons to avoid nuclear reactors, and are briefly described below

The Three Mile Island accident was a partial nuclear meltdown of the Reactor, near the capital city of Pennsylvania, United States. The
reactor accident began at 4:00 a.m. on March 28, 1979, and released radioactive gases and radioactive iodine into the environment. There were no injuries or adverse health effects from the Three Mile Island accident.

The Chernobyl disaster began on 26 April 1986 with the explosion near the city of Pripyat , the resulting steam explosion and fires released at least 5%
of the radioactive reactor core into the environment; Two Chernobyl plant workers died due to the explosion on the night of the accident, and a further 28 people died within a few weeks as a result of acute radiation syndrome.

The Fukushima nuclear accident was in Fukushima, Japan which began on 11 March 2011. The cause of the accident was an earthquake and Tsunami
which resulted in electrical grid failure and damaged nearly all of the power
Plant's backup energy sources ; As a consequence there was a release of radioactive contaminants into the surrounding environment; The accident was rated the maximum severity, following a report by the JNES (Japan Nuclear Energy Safety Organization).

Decommissioning

The decommissioning of a facility can be quite involved and time consuming. There are three ways to decommission:

DECON (Decontamination): Dismantling or removing all radioactive materials above acceptable limits;
SAFSTOR (Safe storage): Leaving the reactor intact but in a safe state. Highly radioactive components such as spent fuel are removed and placed in on-site storage while the surveillance and monitoring continue;
ENTOM (Entombment): Permanently enclosing the facility on site into a condition that will allow the remaining radioactive material to be on-site without ever removing it.

Regardless of the approach adopted, the process can be interminable, often said to be several hundreds of years.

Small modular reactors

Small modular reactors (SMRs) are advanced nuclear reactors which have a power capacity of up to 300 MW(e) per unit, which is about one-third of the generating capacity of traditional Standard nuclear reactors.

The SMRs are the “flavour of the month” in that they are being discussed and promoted quite widely. The only drawback seems to be that there are very few operating on a commercial basis, and the reasons are not exactly clear. However, the advantages can be significant, as some are as follows; Given their smaller footprint, SMRs can be sited on locations not suitable for larger nuclear power plants; Prefabricated units of SMRs can be manufactured and then shipped and installed on site, making them more affordable to build than large power reactors: SMRs offer savings in cost and construction time, and they can be deployed incrementally to
match increasing energy demand: with limited grid coverage in rural areas, an SMR can provide power.

Clearly it is not difficult to imagine the use of the SMR in lieu of the large, distributed power network.

The future

It is difficult to anticipate or predict the future however the following comments are made.

– It is highly likely that the use of nuclear power will increase,
– The cost of the units will decrease with design and construction experience.
– It will become possible to purchase an SME “off the shelf” for appropriate installation.
– Nuclear power will be part of a suite of power sources, as no one source will dominate any market.