on Nuclear Safety and Radiation Protection - Energie EDF

NUCLEAR OPERATING SAFETY: CONTRASTING RESULTS
on the International Nuclear Event Scale in 2012. This also
decreased to 0.8 per reactor and is now lower that for
the French plants. The events corresponding to violations
of the technical specifications for operation substantially
increased (1.67 per reactor), partly due to the way in which
such events are defined to facilitate comparison with the
results of the French plants. I note that, faced with this
deterioration, EDF Energy NG has mobilised an inspection
team to determine the exact causes. The first indications
point to the increasing difficulty with procedure adherence
(compliance with process rules) confirming the necessity -
also in the UK - to simplify procedures wherever possible
so the profession of nuclear operator is made easier.
Plant alignment errors were also the subject of the same
initiative and I will make a point of having progress
reported to me during my visits to these plants in 2013.
At EDF Energy, automatic scrams need to be considered
with manual reactor trips as the British procedures more
frequently require the operators to manually trip the
reactor before the automatic functions operate. The 2012
results show progress (1.48), but are still too far from the
best international levels.
As concerns fire, the increase in the number of outbreaks,
even though minor, confirms that fire hazards need to be
the subject of increasing vigilance and determined action.
During my visits to the plants, I found that the condition of
the fire protection systems could be improved and noted
that there was a management alert (an internal oversight
Level 2 Advice) on one of them. I already pointed out in
2011 that the WANO peer reviews had been finding the
level of fire prevention to be insufficient for a number of
years. The corporate peer review carried out by WANO
at EDF Energy in October 2012 reiterated this point. I am
happy to see that the comparison was launched in 2012
with the French plants and is focusing on the state of fire
protection systems to properly address the needs.
I would like to emphasise the good levels of availability
of the engineered safety features in the Advanced Gascooled
Reactor plants with unplanned capacity loss factors
of 0.3%, 0.1% and 0.3% respectively (WANO indicators)
and the exceptional results for the Sizewell B pressurised
water reactor for which the unplanned capacity loss factor
for these safety systems has been zero for a number of
years. This year, I also observe a reduction in the forced
loss rate (units in service) that has been reduced to 8.9%
(compared with more than 19% in 2010).
Finally, I would like to draw attention to the improved
operating results for the fuel route machines of the
advanced gas-cooled reactors, which have a close
correlation with nuclear safety. The significant progress,
confirmed in 2012, has resulted from the effective use of
a composite performance indicator and the considerable
work performed by the staff.
THE INSPECTOR GENERAL’S REPORT
ON NUCLEAR SAFETY AND RADIATION PROTECTION
In the Constellation Energy Nuclear Group
plants
The number of significant nuclear safety events declared
by Constellation Nuclear Energy Group (CENG) remained
stable at close to 11 per reactor in 2012, the declaration
rules being different in the USA where INPO handles filing
and analysis.
None of the events graded on the INES exceeded Level 1 in
2012, the factor slightly increasing to 0.8 per reactor.
At CENG, as at EDF Energy, it is necessary to consider
scrams combined with manual reactor trips as the
American procedures more frequently require the
operators to manually trip the reactor before automatic
functions operate. The results for 2012 represented a slight
deterioration (0.87 per reactor), far from the achievements
of the period between 2006 and 2009. The results differed
considerably between the Calvert Cliffs, Ginna and Nine
Mile Island plants.
I would like to draw attention to the capacity loss factors
for the engineered safety functions consisting of the safety
injection system (0.2 to 0.45% depending on the plant), the
auxiliary feedwater system (0.1 to 0.9%) and the standby
diesel generators (0.7 to 1.5%). Although these results are
broadly comparable to those of the other reactors in the
USA, they are well below European levels (by a factor of
5 to 10). I am left wondering about the appropriateness
of operating modes for equipment so important for safety
such as the standby diesel generators, and I commend the
action recently begun by INPO to make progress in this area.
I note the good forced loss rate (units in service) for 2012
for the three pressurised water reactors at around 1.5%.
However, with an average factor of 3.1%, the CENG
reactor results are in the lower half when compared with
those of other American operators and vigilance is required.
Although the combined unplanned capacity loss factor
covering units in service and outage extension is very low
compared with the figure for the French installations with
different operating conditions, they have been worsening
slightly over the last five years. I would like to once again
emphasise the positive effect on nuclear safety, for the
entire group, of such a capacity level with as few unit outage
extensions and hence disturbances for the operators.
I would also like to point out the existence of chemistry and
fuel indicators which are given the same importance by the
plant managers as the above.
Finally, I am pleased to see the role played by INPO which
is challenging plants on their performance levels and
setting in place an effective benchmarking system. I must
highlight the significant number of indicators for the
CENG nuclear units which are in the INPO last quartile.
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