Hitchhiker's Guide to Nuclear (Blog and Podcast)

Hitchhiker's Guide to Nuclear (Blog and Podcast)

8 episodes

A podcast concerning the world of nuclear and any tangential topic that comes into our heads!

Podcasts

Podcast Twelve - Godzilla, the EU Earthquake and ITER

Published: June 5, 2014, 9:32 a.m.
Duration: N/A

Listed in: Science

Podcast Eleven - Top Five Nuclear Stories of 2013

Published: Jan. 30, 2014, 9:53 a.m.
Duration: N/A

Listed in: Science

Podcast Ten - We Need to Talk About Korea?!

Published: May 7, 2013, 1:22 p.m.
Duration: N/A

Listed in: Science

Maximum Warp: Nuclear Power and Space Exploration

Published: March 27, 2013, 4:37 p.m.
Duration: N/A

Voyager 2. One of the most distant man-made objects in existence.
The popularised spacecraft don’t actually use conventional nuclear reactors. Radioisotope thermoelectric generators (RTGs) - which harness Plutonium-238 as fuel - are the primary propulsion source. These so-called “nuclear batteries” exploit the principle that plutonium undergoes alpha-decay to produce heat. This is subsequently converted in to electricity using thermoelectric generators. Since they have no moving parts, RTGs are very reliable; the RTG on Voyager 2 has worked continuously since 1977, and is expected to continue working until 2025.

A general RTG configuration
This is not to say, however, traditional nuclear reactors have not also been used in space operations in the past … albeit with some serious modifications. For example, the Soviet RORSAT satellites used 90% enriched uranium fuel as a power source. The safety implications of using such a system in earth orbit are obvious, and any fears of utilising such a technology are not exactly unfounded. The nuclear-powered Cosmos 954 satellite, for instance, fell into Canada in 1978 after a systems failure, distributing 
radioactive debris over 124,000 square kilometres. 

Due to events like these, it is likely that any future reactors will be confined to deep space like RTGs. However, this does not mean that they will only be used for unmanned exploration probes. NASA has its eyes on a manned Mars mission, but traditional chemical rockets would take six to seven months to reach Mars. A 1MW fission reactor powering 100-400 kW electric ion thrusters would take 3 months, thus limiting the health degradation astronauts face on long space journeys.

Modern RTGs are designed to survive the possible accidents which could befall it during operation, including propellant fires during launch and land/water impacts. Reassuringly, RTGs cannot explode like nuclear weapons: the plutonium associated with weapons is Pu-239, not Pu-238. A similar safety feature which has been specified for nuclear reactor propulsion tech is that they are not activated until they are confirmed to have reached space successfully. Ultimately, this is to ensure fission fragments and other components of nuclear waste are not present if failure occurs during launch.

Space: The future of waste disposal?
Lastly, when using an RTG some additional thought must be applied to the disposal of the spacecraft when they come to the end of their working life. This is not just a nuclear issue: it’s important not to disturb any areas which potentially harbour extraterrestrial life. For example the RTG-powered Galileo spacecraft was sent into Jupiter’s atmosphere and destroyed to stop it crashing into a potential ocean under Europa’s crust. The disposal of RTGs and future nuclear reactors actually touch on one of the more outlandish proposals for dealing with nuclear waste: firing it out of the solar system.

In short, the space and nuclear industry have a surprising legacy: nuclear power has already been used successfully for near-earth and deep space missions in the past, and its use has continued into the cutting edge-missions of today. Only time will tell whether or not it is the key to future exploration, both manned and unmanned, into our universe.


DOCUMENT LINKS (IN ORDER OF APPEARANCE)
NASA, 2013 Where are the Voyagers? [online]. Available at: http://voyager.jpl.nasa.gov/where/index.html[Accessed 02/02/2013]
Atmos, J. 2012. Curiosity rover made near-perfect landing [online]. Available at: http://www.bbc.co.uk/news/science-environment-19219782[Accessed 02/02/2013]
Snyder, G.J. Small Thermoelectric Generators [pdf]. Available at: http://www.electrochem.org/dl/interface/fal/fal08/fal08_p54-56.pdf[Accessed 02/02/2013]
NASA, 2013. Voyager – Spacecraft Lifetime [online].Available at: http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html[Accessed 03/02/2013]
Encyclopaedia of Science, 2013. RORSAT (Radar Ocean Reconnaissance Satellite [online]. Available at: http://www.daviddarling.info/encyclopedia/R/RORSAT.html[Accessed 03/02/2013]
HackCanada, 2013. Cosmos 954 Satellite Crash [online]. Available at: http://www.hackcanada.com/canadian/other/cosmos954.html[Accessed 10/02/2013]
King, L, 2012. Manned Mars mission still on track [online]. Available at: http://usatoday30.usatoday.com/tech/story/2012/09/12/manned-mars-mission-still-on-track/57767950/1[Accessed 11/02/2013]
Rousseau, I.M. 2007. Analysis of a High Temperature Supercritical Brayton Cycle for Space Exploration [pdf]. Available at: http://web.mit.edu/rsi/www/pdfs/papers/2005/2005-ianr.pdf[Accessed 01/10/2012]
Discovery, 2013. Known effects of long-term space flights on the human body [online]. Available at: http://www.racetomars.ca/mars/article_effects.jsp[Accessed 10/02/2013].
US Department of Energy, 1982. Nuclear Safety Criteria and Specifications for Space Nuclear Reactors [pdf]. Available at: http://www.fas.org/nuke/space/osnp-1.pdf[Accessed 20/02/2013].
NASA, 2013. Solar system exploration  -Galileo Legacy Site [online]. Available at: http://solarsystem.nasa.gov/galileo/[Accessed 21/02/2013].
The Space Review, 2013. Nuclear waste in space? [online]. Available at: http://www.thespacereview.com/article/437/1[Accessed 22/02/2013]
IMAGES
Space Today Online, 2011. Voyagers are leaving the Solar System [online]. Available at: http://www.spacetoday.org/SolSys/Voyagers20years.html[Accessed 02/02/2013].
Wikipedia, Radioisotope thermoelectric generator [online]. Available at: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator[Accessed 02/02/2013]
Gunter’s Space Page, 2013. US-A[online]. Available at: http://space.skyrocket.de/doc_sdat/us-a.htm[Accessed 05/02/2013]
The Space Review, 2013. Nuclear waste in space? [online]. Available at: http://www.thespacereview.com/article/437/1[Accessed 22/02/2013]



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Listed in: Science

Podcast Nine - The Nuclear Nostradamus

Published: March 5, 2013, 4:13 p.m.
Duration: N/A

Listed in: Science

Episode Eight - A Nuclear Christmas

Published: Dec. 23, 2012, 7:55 p.m.
Duration: N/A

Listed in: Science

Episode Seven - The Nuclear Waste Problem

Published: Nov. 8, 2012, 11:36 a.m.
Duration: N/A

Listed in: Science

Episode Six - There's Something About Iran

Published: Sept. 27, 2012, 8:43 p.m.
Duration: N/A

Listed in: Science