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

SSEM/2011/4730 June 2011large volume NaI detectors. This has enabled not only the practical examination of detectionof alpha sources by X-ray and low energy gamma emission but also the examination of thedetection of Bremsstrahlung for beta sources, which was identified as ‘potentially useful inthe future’ in the 2008 study.While technical progress is evident for two of the other techniques, large inorganicscintillation detectors and large volume High Purity Germanium (HPGe) detectors, this isinsufficient to recommend immediate implementation. It is, however, recommended that atechnology watch is maintained for these techniques as more information may emerge thatwould enable their benefits to be more clearly defined.The practical implementation of FIDLER detectors has provided a reasonable proof ofprinciple for the detection of alpha emitters using X-ray and low energy gamma radiationusing thin crystal HPGe. However, there is insufficient evidence of the performance of thinHPGe detectors to indicate that this method would provide a significant advance inperformance over the FIDLER detection system. It is recommended that the technologywatch be maintained for the thin crystal HPGe technology. These recommendations aresummarised in Table 7.2.For the other techniques reviewed there has either been insufficient technical developmentover the last two years or further analysis has indicated that it is unlikely that they will besuitable for this application within the next 5 years. It is recommended that these are notconsidered further.The conclusion of the BPM review of the potential beach monitoring techniques is that noneare at the level of the current best practice system based on Nuvia's Groundhog TM Synergysystem. The current Groundhog TM Synergy system meets the current beach monitoringobjectives and is expected to do so for the foreseeable future.Table 7.2. Recommendations from BPM assessment.Recommendation Timescale Report Date1. Maintain a technology watch oninorganic detector development withrespect to possible use for large areabeach monitoring.2. Maintain a technology watch on ModularHPGe and thin crystal HPGe detectordevelopment with respect to possibleuse for large area beach monitoring.3. Maintain a technology watch onemerging technology that may providedetector systems suitable for large areabeach monitoring.4. Employ the MOD's technology readinesslevel procedures to judge the abovebeach monitoring technology watch andfor future BPM reports.October 2010 – November2012October 2010 – November2012October 2010 – November2012N/AMarch 2013March 2013March 2013N/A© Nuclear Decommissioning Authority 2011. 105