Since 1997, the United Kingdom Atomic Energy Authority (UKAEA) and NNC Ltd. have embarked on the decommissioning and demolition of a redundant metallurgical facility at Harwell. The metallurgical suite comprised three concrete-shielded remote handling cells and 36 lead-shielded enclosures, with associated support and electron microscopy facilities. The decommissioning work carried out by NNC entails the dismantling of the 36 lead enclosures, which were expected to yield over 1000 tonnes of lead shielding blocks as waste. The decommissioning project is nearing completion, with only two large enclosures remaining to dismantle. This paper describes the management and technical processes utilised in the treatment of the lead blocks, in order to re-use or re-cycle the lead materials as far as reasonably practicable.
In processing 700 tonnes of lead block arisings from the decommissioning of this facility so far, NNC and UKAEA have segregated over 400 tonnes of uncontaminated lead and decontaminated approximately 250 tonnes of lead for unrestricted re-use or for recycling, after smelting. Much of this material would otherwise have been consigned as low level radioactive waste. Secondary low level radioactive wastes arising from the decontamination process have amounted to approximately 15 m3 to date, of which only a small proportion of the arisings are lead shavings.