Office for Nuclear Regulation

THORPE and OFSG - LC32 and LC35 inspection

Executive summary

Purpose of Intervention

In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, each year ONR performs a series of planned compliance inspections of selected licence conditions, targeted at those facilities with significant importance to nuclear safety.

The purpose of this planned inspection was for ONR to determine the adequacy of implementation of the licensee’s formal arrangements for compliance with Licence Condition (LC) 32 (Accumulation of radioactive waste) and LC 35 (Decommissioning) in the Thermal Oxide Reprocessing Plant (THORP) and the Oxide Fuel Storage Group (OFSG) (LC 32 only).  The LC 35 intervention also considered progress with Sellafield Ltd’s (SL’s) preparations for Post Operational Clean Out (POCO) for the THORP facility, following previous inspections carried out in 2017 and 2018.

Interventions Carried Out by ONR

On 12 and 13 March 2019, a team comprising the THORP site inspectors (outgoing and incoming), and specialist inspector in nuclear liabilities regulation and conventional health and safety, carried out two one-day, licence condition compliance inspections of THORP and OFSG.  The inspections comprised discussions with SL staff, a targeted plant walk down and reviews of plant records and other documentation.  This was a joint inspection with the Environment Agency (EA).

LC 32 requires the licensee to make and implement adequate arrangements for minimising, so far as is reasonably practicable, the rate of production and total quantity of radioactive waste accumulated on the site at any time and for recording the waste so accumulated.

LC 35 requires the licensee to make and implement adequate arrangements for the decommissioning of any plant or process which may affect safety.

As part of my preparation for the delivery of this intervention, the current version of the following formal ONR guidance documentation was used:

Explanation of Judgement if Safety System Not Judged to be Adequate

This was not a system based inspection, and therefore no judgement has been made of the adequacy of implementation of any part of the safety case.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

LC 32 Accumulation of Radioactive Waste

From the evidence I reviewed, I found that THORP has continued to make demonstrable improvements in its waste management practices and that these are making a significant contribution to the removal of legacy wastes on plant.  The increased capability demonstrated by the team also gives confidence that effective waste management will continue through the facility’s transition into POCO later this year.

THORP and OFSG were able to provide adequate evidence to demonstrate compliance with the corporate arrangements for waste management; I therefore judged that the licensee has adequately implemented its arrangements for LC 32.

LC 35 Decommissioning

From the evidence I reviewed, I found that SL has continued to make good progress in its preparations for POCO in THORP, demonstrating a systematic and structured approach to planning for those parts of the plant that will enter POCO.  Following the last commercial shear in November 2018, the licensee was also able to demonstrate success in cleaning up some parts of the plant prior to POCO.

I found that the corporate arrangements for POCO remain under review as a result of learning from experience in THORP and I welcomed the iterative nature of the process in terms of assisting other plants on site with their POCO preparations.

THORP was able to provide adequate evidence to demonstrate compliance with the corporate arrangements for POCO and decommissioning; I therefore judged that the licensee has adequately implemented its arrangements for LC 35.

Conclusion of Intervention

On the basis of the evidence sampled during the inspection, I judge that inspection ratings of Green (No formal action) are appropriate for compliance against both Licence Conditions.  This is because I found that SL has adequately implemented its corporate arrangements for these LCs.