Výběr zpráv ze sítě NucNet - 26. týden 2003

IAEA Paks Report Highlights ‘Weak Assessment’ of Fuel Cleaning System

The International Atomic Energy Agency (IAEA) said today (25.6.2003) that the design and
operation of the fuel cleaning tank and system involved in the incident at
Hungary’s Paks nuclear power plant last April was ‘not accomplished in the manner
prescribed by IAEA standards’.

The IAEA’s expert review mission into the incident (see News No. 181, 23rd May
2003) completed its work today. Team leader Miroslav Lipar said, concerning
management, that the team concluded that the Hungarian Atomic Energy Authority
(HAEA) and Paks were “committed to improving the safety of the plant”.
He said the team noted: “That as a result of steam generator decontamination in
previous years, deposits attached the fuel assemblies. A decision was made to
clean the fuel and contract an outside company to develop and operate a fuel
cleaning process. The team found that the design and operation of the fuel
cleaning tank and system was not accomplished in the manner prescribed by the
IAEA Safety Standards. Neither the HAEA or Paks used conservative decision-making
in their safety assessments for this unproven fuel cleaning system.
“The team determined that there was an over-reliance on the contractor that had
been selected for the design, management and operation of the fuel cleaning
system. Time pressure related to a prescribed fuel outage schedule, combined with
confidence generated by previous successful fuel cleaning operations, contributed
to a weak assessment of a new design and operation, which involved fuel directly
removed from the reactor following a planned shut-down.”
On regulatory oversight, the team concluded that the HAEA “underestimated the
safety significance of the proposed designs for the fuel cleaning system, which
resulted in a less than rigorous review and assessment than should have been
necessary”. It also “resulted in the issuance of a ‘licence of principal’ which
lacked the requirement for an expanded review and assessment”.
On the fuel cleaning operation at the time, the team found the contractor
“worked without proper supervision of the Paks plant”. In general, “personnel
involved did not receive adequate training in the safety aspects of this specific
operation”. Additionally, “operating and emergency procedures were not
sufficiently developed”.
On radiation protection, the team found that Paks “undertook appropriate
monitoring and assessments of the radiation exposure to staff”. Based upon the
data or dose assessments provided by Paks and other authorities, the team found
“no indication that the annual dose limits for occupational exposure as specified
in IAEA Basic Safety Standards have been exceeded”. The team also agreed with
the assessment by Paks and the regulatory authority that the annual dose limits
for the general public resulting from the release specified in IAEA Basic Safety
Standards “have not been exceeded”.
The team has provided a number of “recommendations for improvement” concerning
its findings and in “other areas”. A draft of the findings and recommendations
has been handed to the HAEA in the form of “technical notes for factual comment
only”. The IAEA will review the document and submit a final report to the
Hungarian government within one month. The government says it intends to make the
final report available to the public.

Zdroj: NucNet

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