Minutes from SAGE update meeting 4 April 2011
Held in 35 Great Smith Street Whitehall at 10.00
Professor John Beddington Government’s, Chief Scientific Advisor and SAGE Chair
Mike Griffiths (RIMNET)
Hillary Walker (DH)
Jill Meara (HPA)
Paul Tossel (Food Standards Agency)
Terry Donohoe (Food Standards Agency)
Rob Hunter (Civil Aviation Authority)
Tom Plant (MOD)
Jeremy Watson (CLG)
Chris Bradley (FCO)
Arywn DAvies (DEFRA)
Janet Dixon (DEFRA)
Mike Weightman (Chief Nuclear Inspector)
Paul Heaton (Environment Agency)
Graham Forester (Met Office)
Peter Tallantire (Cabinet Office)
George Sallit (DfT)
Nick Gent (HPA)
Tom Rice (NNL)
Andy Hall (Office for Nuclear Regulation)
Anne Glover (CSA Scotland)
John Titley (Environment Agency)
Bill Camplin (CEFAS)
Miles Elsden (GO-Science)
Elizabeth Surkovic (GO-Science)
Chris McFee (GO-Science)
Beth Moore (Cabinet Office)
AGENDA ITEM 1 – WELCOME
1. The CHAIR welcomed everyone to the meeting. He reminded SAGE members that the membership of SAGE would soon be published on line. Full minutes from SAGE meetings would be published as soon as possible once the emergency was over. The CHAIR asked SAGE members to contact the secretariat if they had any problems.
AGENDA ITEM 2 - SITUATION UPDATE
2. SAGE agreed that the general view is that the situation at the plant in Japan appears to be slowly stabilising and concerns of a major atmospheric release are lessening. Any potential hazard to UK nationals living in the Tokyo area is therefore now low. However, we continue to monitor the situation closely.
3. SAGE heard that the Japanese authorities have been trying to adjust the amount of water going into the reactor which is a positive sign and the temperatures from the cores and ponds seem to all be below 50 degrees.
4. SAGE agreed that there was still the potential for explosion from the interaction of molten fuel with the concrete containment, but the potential issue of a hydrogen explosion is now under control.
5. The CHAIR summarised by saying that the view of SAGE was that previous concerns about a catastrophic collapse of core with substantial amount of core being involved was no longer credible, and that the expectation was that any release would be significantly more gradual.
6. SAGE heard that the current forecast is that there is still a risk of Easterly component to the wind, but the general trend is still offshore westerly component. Some rain is expected later in the week but relatively dry over the next few days.
7. Overall, SAGE was told that there had been around 3 or 4 days of significant rain over the plant since the tsunami.
8. CEFAS told SAGE that current advice was no use of local beaches and no consumption of local seafood. Questions remain in terms of further east from site in terms of depositions, but SAGE agreed that it was difficult to give specific advice in terms of what seafood can be eaten.
9. The Food Standards Agency (FSA) told SAGE that any imports will be screened as they come in UK (10% immediate area, 20% wider area) FSA is content with this monitoring. In terms of food, SAGE agreed that plants with the potential for the highest uptake of radioactive produces were green leafy vegetables (such as Spinach) and food bans would need to go on for months due to the contribution from caesium contamination in the area.
10. Summarising, the CHAIR said that it was not currently possible to give clear bill of health to seafood. The main fisheries are believed to be at least 100km away from the Fukushima area, but there was still uncertainty about the exact distance. It was likely that there would be some discharge of contaminated water into seawater. Any discharge should be heavily diluted, but this would need detailed monitoring,
AGENDA ITEM 3 SOURCE TERMS AND SCENARIOS
11. SAGE was told that the Japanese authorities have released results from their ‘SPEEDI’ model – although the detailed information was currently only available in Japanese.
The CHAIR asked Richard Wakeford to liaise with CO and GO science to find out more information about this model.
12. The CHAIR said that SAGE had undertaken detailed assessments of our assumptions behind our reasonable worst case, and on that basis there was nothing in the current Japanese work that led us to question our advice.
13. SAGE was told that, in the very unlikely event the plant had to be totally abandoned due to a catastrophic event, the plant would be able to maintain integrity for around 10 days to 2 weeks.
14. SAGE agreed that that our previous source terms have decreased due to decay of short lived radionucleides – both for reactors and ponds. So a revised, reduced source term was appropriate for the reasonable worst case scenario.
15. Summing up, the CHAIR said that previous advice to COBR had included a worst case, but we now have greater confidence that such a scenario is now highly unlikely
16. SAGE agreed that the current reasonable worst case assessment is still needed, but the actual effective dosage due to iodine needs to be reduced.
MOST LIKELY CASE
17. SAGE agreed that the most likely case is that there are small amounts of radioactivity released from time-to-time in the immediate vicinity of the plant or into the sea, but it was unlikely that an explosive release would occur. However, uncertainty on the plant status could go on for some time as there were still significant unknowns.
18. Summing up the overall discussion, the CHAIR said that that things are still serious. The Japanese authorities have made good progress in improving cooling to the reactors and ponds (particularly by providing fresh water rather than sea water). However, the key was whether water in the ponds was staying there, or whether there was still significant leakage onto the site. SAGE agreed that, on balance, there would not be any major discharges (although our estimates still included a reasonable worst case which included such a scenario), but it was likely that there would be some discharge of contamination leading to problems around the plant over next few months.
SAGE agreed that, given the current uncertainties, it was appropriate to continue to provide our 24 hour emergency response coverage for the foreseeable future. However, this should be reviewed again in a week or so.
LONGER TERM SCENARIOS
19. SAGE agreed that we are not yet in a position to be able to make definitive statements about potential longer term scenarios but we do now need to consider what the longer term hazards are likely to be.
AGENDA ITEM 4
20. The Cabinet Office introduced a paper summarising the science advice on screening would be needed for longer term public health. SAGE agreed that, for current levels of radiation levels up to and including 6mSv, there was no need to introduce modelling on public health grounds,
21. SAGE was told that work had been undertaken looked at any potential risk of low levels of contamination reaching the UK in terms of imported goods. SAGE agreed with the conclusion was there was a risk of this happening, (particularly if our current reasonable worst case occurred). However, based on approximate modelling that up to 10% of containers currently reaching UK shores could carry low levels of radiations, SAGE agreed that these would not breach current health levels but could trigger radiation measurements.
22. SAGE agreed the science advice in this paper
23. The Environment Agency said that they had produced guidance for the UK Borders Agency on the procedures to follow if small amounts of contamination were detected.
The CHAIR asked GO Science, Dft, the Environment Agency and Cabinet Office to ensure that advice was consistent with any other advice we had provided from SAGE.
AGENDA ITEM 5 - TRAVEL ADVICE
24. SAGE agreed that there was no scientific reason why the current travel advice for Tokyo could not be relaxed. SAGE noted in particular that the short decay times of Iodine 131 meant that any contribution from Iodine would now be heavily reduced.
25. However SAGE agreed that we currently do not have a robust scientific reason for reducing the 80km precautionary zone. SAGE heard that, in terms of contamination, the main concerns appear to be for an area around 40km north of Fukushima.
The CHAIR requested the Chief Nuclear Inspector to convene a small working group to provide advice to SAGE on whether there was a scientific basis for relaxing the current 80-km precautionary zone.
26. SAGE agreed that there was now no scientific basis for any advice to consider taking Iodine tablets in the Tokyo area.
FOOD AND WATER
27. SAGE agreed that there was still an issue about water and food. SAGE agreed that UK nationals should continue to follow the advice of the Japanese authorities, and SAGE was content that this advice was robust.
AGENDA ITEM 6 - LONGER TERM MONITORING NEEDS
28. SAGE agreed that our longer term advice was likely to be for UK nationals to follow the health advice provided by the Japanese authorities
29. GO Science introduced a straw man paper outlining potential longer term modelling needs. The CHAIR asked for comments to the secretariat by the end of the week.
30. The CHAIR said that he did not foresee the need for a SAGE in the next week or so, but thought it was likely that there would be a SAGE sometime in the week after that.