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HM Nuclear Installations Inspectorate

MAGNOX ELECTRIC plc

DUNGENESS A POWER STATION

Quarterly report for 1 APRIL TO 30 JUNE 2005

CONTENTS

FOREWORD

This report is issued as part of the Health and Safety Executive's commitment to make information about inspection and regulatory activities relating to the above site available to the public. It is for distribution to members of the Dungeness Power Stations’ Site Stakeholder Group (SSG) and covers activities associated with the regulation of safety at Dungeness A Nuclear Power Station. These reports are distributed quarterly and are also available on the HSE’s web site . Site Inspectors of HM Nuclear Installations Inspectorate attend SSG meetings and will respond to questions raised there by members of the SSG. Any other person wishing to inquire about matters covered by this report may contact the HSE’s Nuclear Directorate Information Centre on 0151 951 4103.

http://www.hse.gov.uk/nuclear/index.htm

Inspections

The Nuclear Installations Inspectorate (NII) Site Inspector and 5 other inspectors visited Dungeness A during the quarter. Inspections were made on the following days: -

11 – 14 April 2005
9 – 10 May 2005
23 – 26 May 2005
7 – 8 June 2005
20 – 23 June 2005

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ROUTINE MATTERS

Compliance Inspections: Routine inspections are undertaken for the purpose of monitoring compliance with (i) the conditions attached by HSE to the nuclear site licences, and (ii) other relevant provisions of the Health and Safety at Work etc Act 1974, including the Ionising Radiations Regulations 1999. In this period routine inspections covered:

Periodic Shutdown. Reactor 2 was shutdown on 8 April 2005 for its final biennial outage. Station staff and contractors undertook inspection, testing and maintenance, activities, which cannot be performed whilst the reactor is at power. Inspections undertaken by NII did not reveal any significant shortcomings in the arrangements or conduct of outage activities. Following a start-up meeting, where the results of the outage were presented and discussed with Station staff, NII then gave formal consent to start up reactor 2 on 13 May 2005.

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NON-ROUTINE MATTERS

Unplanned Reactor Shutdown: On 19 June, following commissioning work on part of the back-up electrical supply system on Reactor 1 an electrical fault led to the breakdown of the reactor temperature monitoring system. In line with station operating instructions the reactor was manually shutdown. A substantial repair programme was then embarked upon and some 2 weeks later the reactor was re-started. The licensee’s investigation and recovery from this event has been monitored and judged to be satisfactory.

Periodic Safety Review (PSR). A requirement of the site licence is that Station performs a major review of safety every 10 years. This exercise requires a review of the existing safety case, a comparison of the plant with modern standards and identification of ageing related effects that may affect safety. The NII then assess the review and decide on future operation of the station based on its findings. Clearly this is an unusual review with the imminent cessation of generation, followed by 2-3 years of defuelling and then the move to a stable care and maintenance regime, which may last up to 50 years or more. NII has begun to assess the PSR reports provided by the Station recognising the forthcoming changes to the lifecycle and gradual reduction in hazard over the next decade. The NII decision date is due in March 2006.

Carbon Dioxide (CO2) Leak. On 25/6/05 there was a large leak of clean CO2 from one of the storage tanks on site. This was due to failure of part of the over pressure protection equipment. The Site declared an incident and people were accounted for on both stations. No one was adversely affected by the gas, which dispersed naturally. Site has reviewed the maintenance arrangements for the relief system and made some improvements, in order to reduce the likliehood of a recurrence.

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REGULATORY ACTIVITY

As part of its regulation under nuclear site licences NII issues regulatory documents, collectively termed Licence Instruments (LI). Three were issued for Dungeness A during the quarter: -

Agreement LI No. 502 – To routine operation of the emergency diesel generators - 7 April 2005

Agreement LI No. 503 – To routine operation of the updated computerised work management system - 17 May 2005

Consent LI No. 504 – Giving permission to start up Reactor 2 following its biennial outage – 13 May 2005.

Under Health and Safety legislation the Site Inspector, or other HSE Inspectors, may issue formal notices to secure improvements to safety. No such notices were issued during the reporting period.

HM Nuclear Installations Inspectorate
Health and Safety Executive
St Peter’s House
Bootle
Merseyside
L20 3LZ

Licence Instruments are formal documents issued under the licence conditions and arrangements, including Consents, Approvals, Directions, Specifications, Notifications, Agreements and Acknowledgements.