Health and Safety
Executive / Commission
Nuclear
LLC reports
This report is issued as part of the Health and Safety Executive's commitment to make infor-mation about inspection and regulatory activities relating to the above site available to the public. It is for distribution to members of the Chapelcross Local Liaison Committee (LLC) and covers activities associated with the regulation of safety at Chapelcross Power Station. These reports are distributed quarterly. Site Inspectors of HM Nuclear Installations Inspec-torate normally attend LLC meetings and will be happy to respond to any questions raised there or subsequently by members of the LLC. Any other person wishing to inquire about matters covered by this report should contact the HSE, Nuclear Directorate Informa-tion Centre on 0151-951-4103.
The HMNII Site Inspector made the following planned visits during the period:
19 - 22 January
15 - 19 March
Other HMNII Inspectors visited the site during the quarter to discuss emergency arrange-ments and the retention of records.
Routine inspections have continued throughout the period to check compliance with the con-ditions attached to the Nuclear Site Licence. During the quarter the station has continued to make improvements to the arrangements for complying with the conditions.
The management and recording of events that occurred on the station during the period were inspected. Most of the events were relatively minor, however two events arose which were investigated further. One event concerned the reporting of a low flying aircraft and the other the use of catch pots and associated grabs. Further details are given in the Section below. The two events were not promptly reported to ourselves, however BNFL has since enhanced its reporting arrangements.
No formal meetings were held during the quarter.
A team from the Inspectorate witnessed a repeat demonstration of certain aspects associated with the 2003 Level 1 Emergency Exercise, in particular command and control (C&C) and cooperation with the fire brigade. The team concluded that, although C&C training had been undertaken since the Level 1 Exercise, the training had not fully "bedded in". Cooperation with the Fire Brigade, which is essential for nuclear safety at Chapelcross, was good.
Further delays were experienced in the production of the safety case for the irradiated fuel pond facilities. BNFL placed an embargo on the handling of flasks in these facilities until the improved safety case was in place.
BNFL produced a revised programme for the installation of equipment that will improve con-tamination control and reduce the likelihood of contaminated persons or materials leaving site.
A BNFL presentation on legacy issues was attended with SEPA. Considerable work had been undertaken on checking land and groundwater contamination and BNFL reported that nothing of significance had been found.
Several BNFL staff reported seeing a low flying aircraft. At the end of the quarter our policy staff were progressing this matter with the Ministry of Defence.
The original design intent of the catch pot grabs was such that fuel elements could not be lifted. However BNFL discovered that a modification to the grabs had undermined this in-tent, and so there was the potential to raise irradiated fuel elements into an unshielded fuel-ling machine. Our investigations into the event revealed that the incorrect use of catch pots, which are used to seal reactor channels, could lead to reactor safety concerns during absorber replacement and reactor power operation. At the end of the quarter BNFL was still investi-gating the event and a safety case covering the use of the catch pots was being prepared.
BNFL provided information to close out some of our findings from our enhanced inspection in September that were linked to the R4 start up. We carried out very little assessment of this information as, at BNFL's request, we continued to diverted resource to the higher priority absorber replacement project.
Some of the safety arguments presented in the safety case covering the above, and in particu-lar fires beneath reactor control rooms, were checked by BNFL. The arguments were found to be not as robust as first thought and BNFL took the conservative decision to shutdown R2 slightly ahead of schedule. A revised case was being prepared at the end of the quarter.
The condition of the above facility, and that of the adjacent decontamination facility, was found to be well below expected standards. BNFL initiated a refurbishment programme and work in the areas will not resume until the condition of the facilities is made acceptable.
Changes to Operating Rule 6 were required to permit the loading of various types of absorber into the reactors, and the amended Rule was Approved during the quarter (see Section be-low).
Considerable effort was diverted during the quarter to assess the safety case covering this project. Agreement was given to replace the absorbers on R3 (see Section below). Replace-ment began, however this was stopped when a damaged graphite sleeve was found in a reac-tor channel. Removal of the sleeve will require the use of catch pots, the safety case for which was being prepared at the end of the quarter. The removal will also require improved health physics procedures and these were also being prepared at the end of the quarter.
Delays to the project meant that the activity of the reactor neutron sources had fallen to such an extent that they could not provide healthy signals to the reactor safety circuits. Healthy signals are needed to permit the raising of safety control rods, which is a requirement when any work is being undertaken in a reactor core. A safety case was being prepared by BNFL at the end of the quarter that would cover the provision of healthy signals via pulse injection.
The Inspectorate has powers under the Nuclear Site Licence to issue Consents, Approvals and Directions. In addition, the Inspectorate uses Licence Instruments to issue Specifications and Agreements under the conditions attached to the Site Licence.
was issued on 6/2/2004. The Approval covers changes to the Operating Rules to permit the loading of various absorbers into the reactors.
(Licence Instrument No 99) was issued on 10/2/2004. The Agreement permits the replacement of absorbers on R3.
Published on the HSE web site13 December 2004
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