Supplementary memorandum submitted by
People Against Wylfa B
HIGH BURNUP FUEL—ITS NATURE AND IMPLICATIONS
FOR STORAGE
A response by PAWB (People Against Wylfa B)
to David Anderson MP`s question at the Energy and Climate Change
Select Committee, 27th January, 2010
1. Burnup is expressed in thousand MegaWatt
days per tonne of uranium. Sizewell B has typically discharged
fuel at 30,000MWd/tU compared with the proposed very high burnup
spent fuel (60,000MWd/tU)
2. The government acknowledges that high
burnup spent fuel from the proposed reactors will be twice as
radioactive as that from Sizewell Bi but the neutron dose rate
(which increases by the power of four with burn up) is stated
to be `not significant for the management of the spent fuel.ii
This is extremely misleading as neutron radiation becomes very
significant over a 100 year storage period and will greatly increase
potential exposure in handling accidents. Whereas a tonne of legacy
spent fuel will emit approximately 33 million neutrons per second
50 years after discharge,iii a tonne of new build spent fuel will
emit 80 million neutrons per secondiv after 100 years of thermal
cooling, exposing the personnel emplacing new build spent fuel
in the period 2125-85 to two and a half times that for personnel
emplacing the legacy fuel.
3. Storage—the nuclear regulators
point out that "extremely long time periods into the future
increase areas of uncertainty not just associated with the spent
fuel itself, but with the long-term integrity of containment structures".v
Despite this, the draft Nuclear National Policy Statement statesvi:
"PWR spent fuel interim dry storage is an established technology
overseas where cask storage systems have been licensed for the
storage of spent fuels from other modern PWRs". Such statements
cannot be applied to the very long term storage of high burnup
spent fuel. After 18 years in cooling ponds the spent fuel from
Westinghouse reactors would be transferred to Holtec Hi Storm
dry casks, licensed for 20 years in the US and assumed to be used
for up to 50 years. No one has any idea how they will stand up
to heat and irradiation over a longer period and the effects of
heat build up on the long term integrity of the fuel is unknown.
AREVA, the French reactor company have designed dry casks but
have decided to store their British EPR spent fuel in ponds until
it can be conditioned. In France, pond storage for up to 300 years
is being condsidered for high burnup spentfuel. It is vital that
the government`s "confidence" in this regard is looked
at criticallyvii when DECC says "in the USA spent fuel has
been safely and securely managed on arising sites for decades
and the US Nuclear Regulatory Commission (NRC) has formally expressed
its confidence that spent fuel can be safely and securely stored
on-site, without significant environmental impact for at least
100 years". However, the great majority of spent fuel in
storage in the US has a burnup of less than 45,000 MWd/tU. A speech
by the NRC Chairman in May 2009viii revealed concerns about high
burnup spent fuel "... there is limited data to show that
the cladding of spent fuel with burnups greater than 45,000MWd/tU
will remain undamaged during the licensing period. Limited information
suggests increased cladding oxidation, increased hoop stresses
and changes to fuel pellet integrity with increasing burnup up
to and beyond 60,000 MWd/tU. These burnup dependent effects could
potentially lead to failure of the cladding and dispersal of the
fuel during transfer and handling operations". Further, the
IAEA puts worldwide experience into context. "... the use
of high burnup and MOX ... fuels will lead to higher residual
heat and will require long heat decay times, implying longer interim
storage period before final disposal".ix
4. Finally, Stefanie Murphy one of the OND
representatives at the Wylfa public meeting 9 January confirmed
that they expected the waste to be stored on-site for up to 160
years, so confirming PAWB`s understanding.
REFERENCESi NDA
Technical Note no. 11339711 Geological Disposal—Generic
Design Assessment: Summary of Disposability Assessment for Wastes
and Spent Fuel arising from Operation of the Westinghouse AP1000
October 2009. Page 25
http://www.nda.gov.uk/documents/upload/TN-17548-Generic-Design-Assessment-Summary-of-DA-for-Wastes-and-SF-arising-from-Operation-of-APPWR-October-2009.pdf
ii Regulatory Justification of the AP1000 and
the EPR. Vol 2—Secretary of State's Proposed Decision para
4.36.
iii Nuclide Importance to Criticality Safety,
Decay Heating, and Source Terms Related to Transport and Interim
Storage of High-Burnup LWR Fuel" I. C. Gauld and J. C. Ryman,
ORNL for Office of Nuclear Regulatory Research U.S. Nuclear Regulatory
Commission. NRC Job Code W6479 December 2000, Fig 18 Neutron source
from 1 metric tonne (t) of PWR fuel; 27.5 GWd/t page 39 http://www.ornl.gov/sci/scale/pubs/cr6700.pdf
iv "Nuclide Importance to Criticality Safety,
Decay Heating, and Source Terms Related to Transport and Interim
Storage of High-Burnup LWR Fuel" I. C. Gauld and J. C. Ryman,
ORNL for Office of Nuclear Regulatory Research U.S. Nuclear Regulatory
Commission. NRC Job Code W6479 December 2000, Fig 19 Neutron source
from 1 metric tonne (t) of PWR fuel; 60 GWd/t page 40.
v Guidance For Inspectors on the Management of
Radioactive Materials and Radioactive Waste on Nuclear Licensed
Sites HSE/NII March 2001, Appendix 3, para 3.6.3.
vi The arrangements for the management and disposal
of waste from new nuclear power stations: a summary of evidence
DECC November 2009. page 15, para 59.
vii The arrangements for the management and disposal
of waste from new nuclear power stations: a summary of evidence
DECC November 2009, para 41.
viii NRC Chairman Dale E. Klein to the Dry Storage
Information Forum Bonita Springs, FL May 12, 2009.
ix IAEA-TECDOC-1089 Storage of spent fuel from
power reactors. Proceedings of a symposium held in Vienna, 9-13
November 1998. Conclusions, page 19.
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