The Nuclear Decommissioning Authority

NDA Sites Monthly Performance Update

General Evaluation - Key Elements

• Work is being delivered for less than expected costs.
• The overall NDA programme is behind schedule.
• Year to date electricity generation is above target.

For financial year 2007/8 with the exception of Sellafield plans are not over pressured. Work is ongoing to assess the funding requirements for Sellafield.

Financial year 2007/8 efficiency targets have been set and the monitoring programme has started.

Year to Date Cost and Schedule Performance
At the end of January 2008, the programme delivered work for less than expected costs. Measured against the year to date budget the programme of work at the end of January is behind schedule.

Please note: We use Earned Value Performance Management to measure programme performance. This compares the budgeted cost of work that was scheduled with the budgeted cost of work that was actually performed to determine schedule performance and the budgeted cost  of work actually performed with its actual cost to determine cost performance.

Year to date electricity generation at the fleet of Magnox nuclear reactors operated by the NDA was above target at the end of January 2008. Electricity generation for the month was above target.

Items of Interest

Key Elements

• Monitoring of the Scottish Solway for radioactive particles is now complete with no finds.
• Trawsfynydd has actively commissioned a brand new active plant for the first time in several years with no significant issues.
• Sizewell A enters a new stage in its lifecycle with passive cooling on both reactors, leading to reduced maintenance and operational routine work.
• At Dungeness A the final connection of the active effluent discharge line allows another area of site to be released for decommissioning.
• On Wednesday 23 January, Cumbria County Council granted planning permission for a new vault at the Low Level Waste (LLW) Repository.
• An incident occurred at the Sellafield Thermal Oxide Reprocessing Plant (THORP) with no observed nuclear safety impact.
• At the Sellafield MOX Plant (SMP) overall the operations portfolio remains behind schedule.

Monitoring of the Scottish Solway for radioactive particles is now complete with no finds. Monitoring of Goat Well Bay is now complete with 5.5 hectares having been monitored with no finds. Monitoring Gillfoot and Southerness is also complete with 13.5 hectares having been monitored with no finds.

On the North Fuel Element Debris (FED) Project at Trawsfynydd, the site has actively commissioned a brand new active plant for the first time in several years. The new Vent Plant is now fully on line and no significant issues have arisen. It was necessary to receive regulatory approval beforehand and, on a Category One case, this is a huge achievement for the Site. Regulator approval of the Safety Case was received at the end of December 2007.

At Sizewell A the Nuclear Installations Inspectorate (NII) has issued a Licence Instrument to allow the site to enter passive cooling on both reactors. This is the culmination of many years of detailed specialist work on the Post Operation & Defuelling Safety Case (PODSC), implementing modifications to the plant then progressively shutting down the powered post trip cooling plant. It has been successfully demonstrated that the decay heat from the residual fuel in the reactors is passively removed by natural cooling, without the need for any forced cooling, and with the reactor core remaining below target temperatures. As a consequence maintenance and operational routine work on the former post trip cooling plant is being progressively deleted.

On Wednesday 23 January, Cumbria County Council granted planning permission for a new vault at the Low Level Waste (LLW) Repository. The construction of Vault 9 is an effective risk mitigation strategy against a shortfall in storage capacity.

At Dungeness A the final connection of the active effluent discharge line was completed during the period in line with the agreement with the Environment Agency. This completes the work to allow discharge of treated waste and effluent off site, permitting the Cooling Water pumps to be taken out of service releasing another area of site for decommissioning.

At the Sellafield Thermal Oxide Reprocessing Plant (THORP) during routine transfer of fuel from the Feed Pond to the Shear Cave, the elevator system failed resulting in the fuel laden carriage unit falling back into the Feed Pond. Initial indications are that all safety features performed as designed and there has been no observed nuclear safety impact. Activity levels are normal and sump levels are unchanged. An investigation is underway and work to recover and repair the elevator is being progressed.

At the Sellafield MOX Plant (SMP), overall the operations portfolio remains behind schedule. Delivery within the period has been disappointing, where significant equipment failure and recovery has constrained throughput. Specifically, significant clashes within the recycle and tray stores resulted in lost production times of 1 1/2 weeks (tray store) and 2 weeks (recycle store). Although back in operation both of these systems have ongoing risk that is limiting throughput.

Safety and Environment Performance

Safety and Environment - Key Elements

• No INES events during the month.
• Four RIDDOR reportable Lost Time Accidents during the month.
• One environmental non-compliance at the LLW Repository during the period and a late reported non-compliance from Windscale has been added to the year to date figures.
• Application submitted to the regulator for the Windscale Site Licence to be transferred to Sellafield six weeks ahead of schedule.

Dosimetry is the measurement of absorbed dose in matter and tissue resulting from the exposure to ionizing radiations.

Nuclear Safety

No events rated at Level 1 or above on the International Nuclear Event Scale (INES) have been reported as occurring at NDA sites during the month.

The failure to complete one element of a Maintenance Schedule inspection of back-up feed equipment in April 2007 at Oldbury (reported last month) has been confirmed as an INES Level 1 event.

The dosimetry assessment for the individual involved in the contamination event in B277 at Sellafield (reported in November 2007) will still take several weeks to complete. The event remains provisionally rated as INES Level 1 and until this rating is confirmed, the event is not included in the total number of events given above.

Application for the Windscale Site Licence to be transferred to Sellafield has been submitted to the regulator. This is approximately six weeks ahead of schedule and will allow regulator to start internal consultation and secure resources for the final assessment inspections.

Dosimetry

The sites provide data on average individual dose, maximum individual dose and collective dose. These metrics are measured separately for SLC employees and for contractors. Note that the dose is measured by a dosimeter which has to be processed before the dose can be added to the record. Therefore dose figures always lag behind the current date. Dose figures are reported by calendar year rather than financial year and the graphs below present the latest figures for dosimeters worn by workers in calendar year 2007 to date. Individual average and maximum doses should be compared with the legal annual limit of 20 mSv.

Radiological Protection

The sites provide data on average individual dose, maximum individual dose and collective dose. These metrics are measured separately for SLC employees and for contractors. Note that the dose is measured by a dosimeter which has to be processed before the dose can be added to the record. Therefore dose figures always lag behind the current date. Dose figures are reported by calendar year rather than financial year and the graphs below present the latest figures for dosimeters worn by workers in calendar year 2007 as processed to date. Average individual doses and maximum individual doses should be compared with the legal annual limit of 20 mSv.

The following graph shows average individual doses. The graph is ordered by employee dose and shows that the Sellafield group of sites received the highest average individual employee doses. The highest average individual contractor doses are also seen at these sites (note that Low Level Waste (LLW) Repository and Calder Hall contractor doses are included within the Sellafield figures) and at Winfrith (due to work being undertaken to remove items of plant from the secondary containment at the Steam Generating Heavy Water Reactor (SGHWR)).

Similar trends are seen in the second graph which shows maximum individual dose. The contractor doses at Bradwell are due to removal of lagging material from the heat exchangers and gas circuits.

Industrial Health and Safety

Four events reportable under RIDDOR happened in the month.

• At Hunterston A, a supervisor slipped whilst ascending a staircase in the pond building causing injury to his shin, head and ribs. His injuries prevented him from attending work for one week and so this event was reported as a RIDDOR Lost Time Accident (LTA). This was Hunterston A’s first Lost Time Accident for 77 months.
• At Sellafield, whilst strimming a gorse bush on the Calder River fence, a contractor felt something hit his inner knee. After examination by the Medical Department he was advised to attend hospital where an x-ray revealed a foreign body located behind the knee. The person has been unavailable for work for greater than 3 days and so this event has been reported as a RIDDOR Lost Time Accident (LTA).
• An employee was attending a National Vocational Qualification (NVQ) presentation at the Sellafield Visitors Centre. On congratulating him, a team member subjected him to an over-enthusiastic embrace causing bruising to his ribs. This has led to greater than 3 days lost time and the event has therefore been reported as a RIDDOR Lost Time Accident (LTA).
• At Sellafield, a contractor injured their neck whilst working in a kitchen. The event was subsequently reported as a RIDDOR greater than 3 day Lost Time Accident (LTA) by the employer.

In a further event at Sellafield, whilst walking across a zebra crossing, a UKAEA employee was struck by a car and sustained a broken wrist. The person was detained in hospital for greater than 24 hours. The event has been reported as a RIDDOR Major Injury to a member of the public as the individual was not working on the Sellafield site and was on his way to work at the Windscale site.

Environmental Protection

One environmental non-compliance has been reported in the period.

• The Low Level Waste (LLW) Repository has received a warning letter from the Environment Agency in response to a number of events involving the site environmental monitoring arrangements. The letter identifies that the site failed to meet fully the requirements of the Radioactive Substances Act (RSA) authorisation in a number of areas but recognises that these were mostly historic issues identified by the site as part of the scrutiny that went into setting up the new LLW Repository SLC. This is a Category 4 event in the Environment Agency’s Compliance Classification Scheme.

In addition, a late reported non-compliance from Windscale has been added to the year to date figures, for discharge information that was recorded at the appropriate time but was not reported to the Environment Agency within the timescale defined in the Discharge Authorisation.