Nuclear Waste

The International Panel on Fissile Materials has stated that “placing spent nuclear fuel in repositories hundreds of metres below the surface would be safer than indefinite storage on the surface”.  Many countries have come up with experimental test sites that have proved unworkable (German salt mines, US Mt Yucca, French shales below their vineyards).  The solutions to date in salt, sedimentary rocks and volcanics have been found deficient with the latest test sites now in granites. This latest plan uses the Swedish KBS-3 technology and test sites are being prepared in Sweden and Finland. Note that these are considered research sites and have no history of success. 

South Australia has accepted this as the best technology and has based their current proposals on it.  The Swedish solution is to store the waste locally for at least 30 years to reduce the heat produced. The waste is then encapsulated in cast iron, then in a copper alloy, then buried in crystalline rock and covered in bentonite clay and finally sealed (by unknown material?).

The Swedish waste is being buried within 5 km of the nuclear reactor at Fosmark. The waste is not allowed to be exported by law. It is also buried in a location where any underground leakage will go out to sea and not pollute groundwater.  The site must also be in a low earthquake zone and protected from criminal elements. Note that the encapsulated material is expected to never leak.

Note that a desert site is not suggested as this gives no protection.  Deserts undergo geological processes such as floods and wind. Floods move waters underground and in surface drainage systems.  Winds create severe dust storms spreading particles far and wide.  Dust from the radioactive Maralinga site would have been blown across the eastern states for the period it was left uncovered. Australian deserts also have a high biological population as well as a significant indigenous and pastoral population.

For South Australia this negates anywhere in the east, north and west of the state where the Great Artesian Basin (GAB), Arckaringa Basin, Officer Basin, Pedirka Basin and Eyre Basins lie.  The Flinders Ranges are out due to high seismicity.  This leaves the Eyre Peninsula. Minimal transport and underground leakage to sea would require a coastal location, preferably near a workforce to manage the project. Somewhere near Whyalla, avoiding the local deposition systems,would probably be scientifically the best spot.

Then there is the politics !!  Nuclear materials are best handled in the local area of production and not pass though multiple administrations. They are best disposed in geologically stable regions, not remote regions (harder to protect).

Solar Thermal

It is great to see Phase 1 of the Moroccan Solar Thermal plant up and running. The plant focusses solar energy using an array of 500 000 mirrors, which store heat in molten salt, which is used to drive a steam generator. It is currently a 160 MW plant which can operate during daylight hours plus 3 (until the heat is dissipated). It is described as a “wet” plant as it uses significant quantities of fresh water to keep the mirrors clean. 

Phase 2 and 3 expect the plant to increase to 2 GW in the next few years, including a field of solar cells and other unknown “dry” technology and is expected to supply near 24 hour power without using batteries! 

Cost to date is of the order of US$3 billion with the full plant estimated at US$9 billion.  The design expertise (Spain, Saudi) and capital input (France, Germany, World Bank) have been heavily subsidised but also has a large Moroccan input.  Europe is keen to send clean solar energy north, while the World Bank and Morocco want more electricity available to Africa.

Until now Morocco imported 97% of their energy needs and have just taken a big step towards a green technology and energy self sufficiency.  They have a large wind project on its way (another 2 GW) and 2GW of hydro to give the country 42% green energy by 2020.

Additionally they are hedging their bets and building a US$4 billion LNG plant so they can import and store natural gas.

South Australia is considering a Solar Thermal power station at Port Augusta. It will require a large government cash input, both local and federal.  It is a great idea but will need significant technical and economic consideration.  It will need to supply energy after daylight is over and will need to consider its fresh water usage to be useful to the Australian energy scene.

Sundrop farms currently use solar energy to heat their tomato greenhouses in Port Augusta and also provide desalinated fresh water.  The system is backed up by gas heating at night and during cooler weather. 

South Australia is a world leader in solar technologies and must keep up its expertise.  There are still many hurdles to be overcome.

Space Solar

Another emerging solar technology is space solar.  The Earth’s atmosphere scatters and absorbs most of the sun’s incoming energy.  Solar energy can be collected in space for 24hours a day without absorption losses and with no clouds in the way.  This energy can be transmitted back to Earth either by lasers (dangerous) or microwaves ( benign if spread over a large area).

A space race is currently on to solve the remaining problems and make the process cheap enough. China, US, Japan are all in the race with Japan suggesting that they will be producing a GW by the 2030s.  A big problem is the amount of material required to build the solar cells and associated machinery  in space.  With current materials, a cost of $150 per kg to get into space is required (which seems unlikely in the near future).

The future appears to be in reducing the weight required by a large amount.  Another possibility is to mine asteroids for materials.  Currently, the development of reusable rockets will also speed up the process.

Which brings us back to Elon Musk.  Another of his companies is Space X and their major project is reusable rockets.  He was belittled by many saying the technology was out of reach, but he has nearly perfected the process.  His last re-entry rocket landed safely on a barge, but then one leg collapsed, the rocket fell over and blew up!!

Personally, I like Elon Musk.  He is the real live model for Iron Man, although I think of him more as a modern Howard Hughes.  His other company is trying to build a pneumatic transport system where people and goods are placed in a cylinder in a tight fitting tube and then whizzed in a near vacuum to the next port.

Elon is not keen on Space Solar, even though it may be a great project for his Space X rockets.  He thinks that the many transfers of energy needed with current technology ( solar to electricity to microwave to electricity) will make the system unprofitable!  It may also make his battery system unprofitable 

The system still has many technology and political issues to overcome. Everyone will want assurances that the system won’t be used to build death rays for example.

Watch this space!! 


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