Talk:Advanced Gas-cooled Reactor

Noble gas coolant for higher temperature
What about noble gas coolants? Do noble gases have high neutron cross sections? If not, then you might be able to have a graphite/tungsten carbide walled, noble gas (argon, helium, neon, xenon, krypton) cooled reactor reach 2000-2500C operation temperature, giving extreme theoretical thermal efficiency in a noble gas fluid based heat engine of 90% (i.e. carnot limit=1-273K/(273K+2500C))=90.1%), meaning only 10% waste and thermal pollution compared to 30-40% efficiency and 60-70% waste heat as with current reactors. Water and steam as a thermal fluid (and turbines based on them) would be totally out of the question in this scheme because at 2500C water thermolyses to oxygen/hydrogen, plus even as undecomposed as water it corrodes/dissolves wall materials. There could be coolant water attached to the low temperature end of the closed-loop heat engine (such as Stirling engines), at the 0-100C end that removes the waste heat. Sillybilly 04:20, 9 November 2006 (UTC)


 * Helium was certainly a possibility, but in Europe largescale supply was difficult back in the days Magnox/AGR were designed - the U.S. would not export it as a strategic material, see . Have you looked at the modern Very high temperature reactor and Pebble bed reactor designs? Rwendland 10:36, 9 November 2006 (UTC)

BBC radio program on recent AGR problems
FYI BBC Radio 4 program on the recent AGR problems (cracks in graphite and cooling pipes) "File On 4: Nuclear blackout?" can still be listened to on the internet at. Transcript at. Rwendland 22:40, 13 December 2006 (UTC)

article : factual error !
--Lightness1024 (talk) 23:13, 28 April 2008 (UTC)

sorry i dont know how to deal with wiki discussion threads, though, in the article, it is said that the first commercial operation is 1976, however in here: http://en.wikipedia.org/wiki/Bugey_Nuclear_Power_Plant it is said that one AGR is fired up on 1972. (in france yes, not UK, so is that figure of 1976 a figure only valid for UK ? if yes, it would be nice to improve the clarity of the article, thanks.)
 * Bugey 1 was definitely a gas-cooled reactor but I don't think that it was an AGR which was a specifically British concept. For example, I understand it used metallic uranium not uranium oxide fuel and the basic design was different. Dabbler (talk) 23:41, 28 April 2008 (UTC)

AGR Secondary / Tertiary Shutdown/Holddown Systems
I worked on the boron bead injection system for Hartlepool / Heysham A and the nitrogen injection system for Heysham B in the 1970s and early 1980s. My recollection is that Hartlepool / Heysham A had the boron beads as the secondary shutdown (SSD) system whereas Heysham B had the nitrogen gas as SSD.

The article currently implies that all AGRs have nitrogen SSD, but I don't recall this on Hartlepool / Heysham A. As Heysham B was a development of Hinckley Point B, could it be that Hinckley Point B and Hunterston had nitrogen for SSD and Hartlepool / Heysham A boron beads for SSD, and that the NII are now asking for boron beads for Heysham B? And what about Dungeness B's SSD? Fsbr1908 (talk) 15:15, 7 December 2009 (UTC)


 * I worked at Hartlepool and later Heysham A but not specifically on the reactor construction. As far as I recall, the reference given dates from the time before the boron bead shutdown system was decided upon and installed. I seem to recall there was a nitrogen shutdown injection at Heysham A (Hartlepool was nowhere near completion when I was there but Heysham was close). The problem I recall being discussed with the boron beads, was recovering them if you ever had to use the system and then wanted to restart the reactor. Dabbler (talk) 15:41, 7 December 2009 (UTC)

I worked on the Heysham A / Hartlepool in 1975 and I'm pretty sure it was referred to as the SSD system then. I don't recall any nitrogen injection system on these reactors, certainly not as SSD. Oh, and you are right about getting the beads out. It was easy enough to get them in, they pretty well floated in the CO2 at 600 psi and were just dumped into gas streams from hoppers, but getting the little blighters out again was another story. . . Some wag called it the TSD - T for Terminal, not Tertiary. Fsbr1908 (talk) 10:07, 8 December 2009 (UTC)

Heysham 2 (or B) and torness do have an n2 secondary hold down system which is initiated automatically on a rod insertion fault or manually if required. They also have as an initial design a tertiary shutdown system using boron beads which is manually initiated only. The beads are designed to be recoverable. — Preceding unsigned comment added by 86.159.180.172 (talk) 19:18, 25 December 2012 (UTC)

cooling the graphite
The AGR design section says "a re-entrant flow of coolant at the lower boiler outlet temperature of 278°C is utilised to cool the graphite" but the schematic diagram doesnt seem to show this or explain how the graphite can be cooler than the CO2 or steam outlet temp. Rod57 (talk) 15:42, 18 March 2011 (UTC)

Some of the 300 degree co2 flows up between the core restraint tank and the gas baffle then flows down through channels in the core then joins the main flow up through the fuel channels where it picks up heat to 637 peak. Obviously orifices in the sub core area provide the diff pressure to drive the re-entrant flow. In fact some of the cool gas flow flows through various cooling nozzles such as the dome tundishes and boiler restraints to maintain design temperatures around the core. — Preceding unsigned comment added by 86.174.140.240 (talk) 23:12, 13 January 2013 (UTC)

Shutdown procedures
Can anyone add content or links for shutdown and safety issues, systems and procedures eg as compared to BWRs and PWRs ? Rod57 (talk) 15:42, 18 March 2011 (UTC)

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Current AGR reactors
I dont understand the 'commercial operation' date for the listed reactors. Eg, heysham 1 operating at full load before heysham 2 was commissioned. Where do the dates come from ?, link ? — Preceding unsigned comment added by 81.136.53.102 (talk) 09:35, 5 March 2018 (UTC)