Annual Report for 2010/11 and Forward Programme - Sellafield Ltd

SSEM/2011/4730 June 2011Table 3.4. Changes in find classification since 2006.Classification 2006/07 2007/08 2008/09 2009/10 2010/11Alpha-rich 1 31 24 142 322Beta-rich 11 315 218 94 60Cobalt-rich 0 5 2 5 1All 12 351 244 241 383The large increase in find rate at St Bees (see 3.1.5.3) is likely to be the result of Synergy as57 finds, out of 60 recovered in 2010/11, were classified as alpha-rich (Figure 3.10). Findsdetected on other beaches such as Drigg, Whitehaven and Harrington have all beenclassified as alpha-rich except for one beta-rich find in Whitehaven Harbour (Table 3.5). Thelarge number of alpha-rich finds provides further evidence of the capability of Synergy fordetecting low energy radiation. A total of seven beta-rich finds and one Cobalt-60 rich findwere recovered from Braystones beach but the remaining 107 were classified as alpha-rich.No beta-rich finds were recovered from Drigg, Seascale or Harrington during 2010/11however beta-rich finds have been recovered on Drigg and Seascale beach in previousmonitoring years. This is further evidence that the “population” of beta-rich finds maybe beingremoved faster than they are becoming available in the beach environment.350300Total number of Finds250200150100Alpha-richBeta-richCobalt-rich5002006/07 2007/08 2008/09 2009/10 2010/11Monitoring YearFigure 3.7. Changes in find classification since 2006.© Nuclear Decommissioning Authority 2011. 27