Health and Safety
Executive / Commission
Nuclear
LLC reports
This report is issued as part of the Health and Safety Executive's commitment to make information about inspection and regulatory activities relating to Heysham Power Station available to the public. It is for distribution to members of the Heysham Local Community Liaison Council and covers activities associated with the regulation of safety at Heysham. These reports are distributed quarterly. Site Inspectors of HM Nuclear Installations Inspectorate attend LCLC meetings and will respond to any questions raised there by members of the LCLC. Any other person wishing to enquire about matters covered by this report should contact the HSE, Nuclear Directorate Information Centre on 0151-951-4103.
The Nuclear Installations Inspectorate (NII) site inspectors made visits to Heysham on the following dates during this quarter:
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Heysham 1 |
Heysham 2 |
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15, 16, 19, 20 January 2004 |
13, 20, 21, 22, 27 January 2004 |
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4, 5, 11, 12, 14 February 2004 |
5, 6, 11, 24, 25 February 2004 |
|
10, 11, 16, 30, 31 March 2004 |
5, 10, 11, 16, 17 March 2004 |
Other members of the NII, including specialist inspectors visited the Heysham site during the period, as follows.
The NII site inspector, superintending inspectors and specialist inspectors attended site on a number of occasions during the period in relation to matters associated with the failure of the ECW seawater cooling pipework.
Handover activities were completed to effect a change of NII site inspector for Heysham 1. This is in line with the NII policy of changing the site inspector after a period of 3 to 4 years.
The NII site inspector, a superintending inspector and specialist inspectors attended site on several occasions during the period to inspect matters associated with events on the site, the unplanned trip of reactor 8 in October 2003 and commissioning of the fuel route.
As part of our routine work we inspect for compliance against the requirements of the Stations' Nuclear Site Licence Conditions and the arrangements made under them, the Health and Safety at Work Act and other relevant safety legislation. We sample activities on site that may affect safety, and in this report include details of the following matters.
British Energy has announced changes to power station management structures, which are intended to improve operational focus and the management of work. Many of the organisational changes are in response to findings from peer reviews of station performance in key areas, and particularly those performed by the World Association of Nuclear Operators at BEG stations. BEG also expects to introduce further changes as they implement the recommendations from the company Performance Improvement Project. The changes are intended to improve station operational performance, and in some areas they may also benefit safety at the stations. NII will continue to monitor the implementation of these changes to be satisfied that BE is managing adequately aspects related to nuclear safety.
Further discussions have taken place during the current period concerning the on-site emergency plan, which is approved by NII, and in particular the arrangements made for notifying the public within the Detailed Emergency Planning Zone (DEPZ) of a radiation emergency, in the event that this should become necessary. NII has requested the licensee to submit for approval, an amended Site Emergency Plan to reflect changes made in relation to such notifications, frequently termed the 'Warn and Inform' function. And for the changes to reflect the statements made on the Public Information Calendars for 2004, already distributed to persons within the DEPZ.
A periodic shutdown (Outage) will take place on Heysham 1 Reactor 1 commencing in August 2004. An outage intentions meeting was held with the licensee and represents the starting point to this significant nuclear site licence compliance activity. NII inspectors assessed the station's outage proposals to ensure that the inspections and maintenance to be carried out would be sufficient to support the station safety case for a further period of operation. Specific areas discussed included inspections to the reactor core and pressure vessel together with nuclear safety related improvements and plant modification work. Some generic aspects of outage management were reviewed with an emphasis on human performance to ensure the work is completed to a high standard and assessing controls to be used to minimise radiological dose uptake to all staff. The NII site inspector and his team of specialist assessment inspectors will have a continuing inspection and assessment role through to completion of the outage. The outcome of the inspections will inform NII's decision as to whether the station has made an adequate case to operate the reactor for a further period.
Following an unplanned trip of reactor 8 in October 2003, covered in the last quarterly report, station has presented to NII the results of the divisional panel of inquiry into this event. In its report the panel made recommendations covering plant improvements and operational practices in many areas, which station is currently working to address. The Heysham 2 NSC accepted the safety case for the long-term operation of the gas circulator variable frequency drive equipment, which was considered as part of the inquiry, in April 2004.
We also respond to non-routine matters arising on site that may affect safety, and in this report include details of the following matters.
As part of our inspection activities at the site we investigate safety related events that occur and follow-up those which are perceived initially to have the potential to be more significant, we particularly examine the licensee's response to such events. From our inspections in this quarter we are satisfied that events which occurred did not represent a significant challenge to the safety case, and response by stations has been in accordance with appropriate arrangements. We summarise our reaction to the selected events as follows.
The following events were followed up at the station during this quarter.
A review of weld inspection records at Heysham 1 revealed non-conformances against Maintenance Schedule (MS) requirements. A full investigation has been completed by the licensee to establish the root cause of the event. Corrective actions have been put in place and the welds have been satisfactorily inspected. The station has reviewed similar systems and concluded all necessary welds have satisfactory inspection histories. NII was satisfied with the investigation and noted there the event information has been shared within British Energy through the Operation Experience Feedback (OEF) system.
Following an operation to de-isolate part of a water cooling main within the Additional Fuel Build Facility (AFBF) the control room received alarms informing the operators of a water leak. On investigation it was found that the flanged joints had separated on the cooling water main pipework. The station investigation concluded the root cause of the Event was a human error in failing to follow fully the procedure for the de-isolation and return to service of the plant. Station is taking action to improve human performance. NII was satisfied with the station's investigation and will continue to press for further improvements in the area of human performance and procedural adherence.
Both reactors at Heysham 1 were shutdown on 28 October 2003 due to the failure of a section of cast iron pipework within the Essential Cooling Water (ECW) system. Following an extensive programme of pipework replacement and other nuclear safety improvements a return to service safety case was presented to justify the return to service of the station. NII's agreement to the return to service of the reactors was provided on 14 February 2004.
The following events were followed up at the station during this quarter.
Station reported to NII a compliance shortfall with the safety case for fuel handling at Heysham 2. The event concerned the station's discovery that a check of the decay store closure number at the end of a fuel stringer exchange was not included in the operational procedures. The checks are part of the fuel route safety case and are claimed in the assessment of risk. Station reported that the controls to prevent this event were both redundant and diverse, and they remained confident that these additional provisions, providing defence in depth, would prevent mishandling of the fuel. They also reported that a review of fuel handling has revealed that no instance of incorrect transfer of a fuel assembly has ever occurred at Heysham 2. Station took prompt corrective action to address this shortfall which station themselves had identified, and an embargo on fuel route transfers was put in place until the administrative control was included in the operational procedures for future handling of fuel.
Station reported that a gradual increase in boiler feedwater delivery pressure had developed over a number of months on reactor 8 affecting all boilers. They initially reduced power by 25 MW(e), to allow the delivery pressure to be returned to normal levels. Station investigated and established an event recovery team, which included company specialist support staff. At all times system operating parameters remained within those allowed by the plant safety case. Station provided a justification for continued operation of reactor 8, which also covered operation of reactor 7 at Heysham 2. Station confirmed that no similar increase in feedwater delivery pressure had been observed on reactor 7. They identified potential flow restriction sites within the boiler feedwater tube system, and plan to inspect these sites, by direct examination or remote viewing, during the forthcoming outage of reactor 8. Following this event, station identified a potential IOI compliance issue associated with the operational configuration adopted for the boiler feed pump suction strainers. It has been station practice to have the standby strainer isolated but available for use with operator action. A conservative interpretation of the IOI requirement is that if a suction strainer is isolated, it is not available and must be entered as such on the system, which monitors plant configuration. However, in the past where the strainer has been available for manual connection but isolated from the system, it has not been deemed to be unavailable. Station adopted a conservative interpretation of "available" and reported the circumstances as a separate event from the anomalous pump delivery pressure condition, which revealed it. This interpretation will be used in the future to decide on the need to declare equipment unavailable. Station took prudent action to mitigate development of the anomalous delivery pump pressure condition, and took a conservative decision in deciding on plant availability. They are taking steps to identify appropriate remedial action in the longer term.
Station discovered and notified NII of a shortfall in testing of the reactor flux detection equipment. Station reported that periodic operational tests on the neutron flux monitoring instrumentation had been replaced by alternative tests during a work optimisation exercise. However, station work control systems were not completely revised to reflect the intended changes with the outcome that some tests were not carried out. Station is satisfied that the reactor flux detection equipment remained fit for purpose, and has ensured that any outstanding testing has been addressed. Diverse testing is specified for this equipment, and this additional testing was carried out successfully, and therefore the safety significance of the omitted testing was reduced. They confirmed that in future the tests will be covered by improved arrangements and therefore such an omission should not recur.
The following regulatory documentation was issued during the quarter:
This confirms the initial notification given in advance in the last quarterly report.
Published on the HSE web site 27 July 2004
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