http://www.powermag.com/frances-nuclear-storm-many-power-plants-down-due-to-quality-concerns/
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France’s Nuclear Storm: Many Power Plants Down Due to Quality Concerns
11/01/2016 | Lee Buchsbaum
[Note: This article will appear in the forthcoming December 2016 print
issue of POWER.]
The discovery of widespread carbon segregation problems in critical
nuclear plant components has crippled the French power industry—20 of
the country’s 58 reactors are currently offline and under heavy
scrutiny. France’s nuclear safety chairman said more anomalies “will
likely be found,” as the extent of the contagion is still being uncovered.
With over half of France’s 58 reactors possibly affected by “carbon
segregation,” the nation’s nuclear watchdog, the Autorité de Sûreté
Nucléaire (ASN) has ordered that preventative measures be taken
immediately to ensure public safety. As this story goes into production
in late October, ASN has confirmed that 20 reactors are currently
offline and potentially more will shut down in coming weeks.
The massive outages are draining power from all over Europe. Worse, new
questions continue to swirl about both the safety and integrity of
Électricité de France SA’s (EDF’s) nuclear fleet, as well as the quality
of some French- and Japanese-made components that EDF is using in
various high-profile nuclear projects around the world.
Backbone of the French Grid
EDF’s nuclear power plants (NPPs) provide up to 75% of France’s power
needs. Its NPPs are spread out over 19 sites and include 34 900-MW
units, 20 1,300-MW units, and four 1,450-MW units. As the fleet suffered
through shutdowns, inspections, and reviews, production fell in
September to its lowest level since 1998—just 26.6 TWh, according to
French grid operator Reseau de transport d’electricite.
With more NPPs scheduled to go offline, that figure may continue
falling. Earlier in October, EDF reduced its 2016 generation targets
from 395–400 TWh to 380–390 TWh, while estimates for nuclear output in
2017 have also been lowered to between 390 TWh and 400 TWh. For
perspective, annual nuclear production averaged 417 TWh in the period
2005–2015. Although in 2009 output fell to 390 TWh, for the last decade
production has consistently been above 400 TWh and exceeded the target
range of 410–415 TWh in both 2014 and 2015.
Following EDF’s reduced nuclear generation forecast, wholesale power
prices immediately began jumping with Q4 2016, Q1 2017, and calendar
2017 baseload contracts trading up by €1.70/MWh, €1.65/MWh, and
€1.20/MWh, respectively. To address the energy shortfall, France is
turning to coal and other fossil fuels, as well as imported power.
Despite the COP21 carbon emissions agreement, which recently went into
force, France is now burning coal at its highest levels in 32 years.
Despite the COP21 carbon emissions agreement, which recently went into
force, France is now burning coal at its highest levels in 32 years
With so many plants now offline, Reuters reported that French wholesale
2017 power prices hit a contract high of €45.60/MWh on October 27, with
more gains possible in the coming weeks and months. Additionally, prices
in Germany, Europe’s largest power supplier, are also rising. As that
nation diversified its power sources and bulked up its renewable
capacity, much of its conventional fleet has become underutilized or
marginalized. Many of those German plants are now revving up as they
send power into France, thanks to a high level of interconnectivity. Not
coincidentally, Reuters reported that German year-ahead power prices hit
a two-year high of €33.65/MWh in late October as well.
Questionable Materials and Documentation
At the heart of France’s nuclear crisis are two problems. One concerns
the carbon content of critical steel parts, steam heat exchangers, and
other components manufactured or supplied by AREVA SA, the French
state-owned nuclear engineering firm and global producer of nuclear
reactors. The second problem concerns forged, falsified, or incomplete
quality control reports about the critical components themselves.
Excessive levels of carbon in the steel parts could make them more
brittle and subject to sudden fracture or tearing under sustained high
pressure, which is obviously unacceptable. Initially discovered at the
troubled 1.65-GW Flamanville 3 project (Figure 1) in 2014—one of the
first in the vaunted European Pressurized Reactor (EPR) nuclear plant
series that EDF also plans to use at the newly approved Hinkley Point C
plant in England—more flaws have since been discovered throughout the
existing nuclear fleet.
An internal probe of the forge at Le Creusot (Figure 2), where many of
the components in question were created, has uncovered new anomalies.
According to an October Bloomberg report, AREVA is now reviewing all
9,000 manufacturing records at the forge dating back as far as 1943,
including files from more than 6,000 nuclear components.
Though there have been questions raised since anomalies were discovered
at Flamanville in 2014, during the past six months—and accelerating this
fall—almost weekly revelations have resulted in plant shutdowns,
extended outages, reduced generation, and lots of questions. Following
parliamentary hearings on October 25, resulting in a wider probe and
likely more plant shutdowns, on October 27, ASN confirmed with POWER
that the scope of the problem appears to be expanding.
According to an ASN press relation’s officer, who requested anonymity in
line with ASN rules, there are now a significant number of reactors
offline, with more to be inspected in the next few weeks. “We are now
finding carbon segregation problems from components coming from both Le
Creusot and [the Kitakyushu-based Japan Casting & Forging Corp.] JCFC
plant. As for now, there [are] 20 EDF reactors offline,” the official
said, noting that the number will fluctuate as inspections take place.
Some examinations were scheduled during refueling outages and normal
periodical reviews. Among affected NPPs, “ASN is performing inspections
on seven reactors equipped with steam generator channel heads
manufactured by JCFC that are liable to contain a particularly high
carbon concentration,” explained the ASN press relation’s officer. The
seven plants are: Bugey 4, Civaux 2, Dampierre 3, Gravelines 2,
Saint-Laurent-des-Eaux B1, and Tricastin 1 and 3.
In early October, ASN weighed in on the deteriorating situation and
ordered EDF to cease generation from five other units. It wants safety
tests conducted on all of those nuclear reactors and steam generators
because of the additional carbon anomalies discovered. The tests, which
will take place between November and January, will require the shutdown
of the following units: Civaux 1, Fessenheim 1, Gravelines 4, and
Tricastin 2 and 4.
“All together, there will be a total of 12 reactors inspected for the
carbon segregation issue. This examination will take several weeks or
possibly longer. There is carbon segregation and some other metal
elements are being checked in every nuclear plant,” the ASN
representative continued in an exclusive interview with POWER.
On October 25, Reuters reported that EDF and ASN had delayed the restart
of Civaux 2, Dampiere 3, and Gravelines 2 NPPs. In addition, it said
there had been more irregularities detected at Gravelines 5.
Though the problem has worsened in recent weeks, upon receiving EDF’s
early preliminary safety assessments in June, ASN immediately deemed
that 12 NPPs were at risk and ordered that those plants be operated
under strict precautionary conditions. Unsatisfied, in October ASN
ordered EDF to shut down all of the 12 affected NPPs until tests could
be completed and, potentially, components fixed or replaced. According
to ASN, because these components are essential for safety, “the quality
of their design, manufacture, and in-service monitoring is therefore
extremely important.”
The analyses performed by EDF thus far have found that since 2015
certain channel heads of the steam generators manufactured by Le Creusot
and JCFC “contain a significant carbon concentration zone which could
lead to lower than expected mechanical properties,” according to an ASN
report. These steam generators equip 18 reactors in the 900-MW and
1,450-MW plant designs. Of these reactors, 12 are equipped with
high-carbon channel heads. According to The Japan Times, the JCFC is now
also under scrutiny by Japan’s Nuclear Regulation Authority as each of
the JCFC supplied plants have become part of the probe and may
eventually prove to be the most affected.
Effects Felt Worldwide
Energy traders and analysts now warn that the French market needs to
prepare for longer maintenance periods in coming years given the age of
the nuclear fleet and the continuing design flaw revelations. With the
average French reactor now more than 30 years old, equipment will need
to be replaced more frequently, and increasingly stringent safety
requirements will mean that components could be delayed, especially as
ASN imposes additional checks. The safety inspections and other reviews
“will lead in particular to extensions of certain planned outages,” EDF
said in a press release.
The safety inspections and other reviews “will lead in particular to
extensions of certain planned outages,” EDF said in a press release.
However, even before this current situation, France, like neighboring
Germany, had begun to question the safety and future of nuclear energy
post-Fukushima. Since that 2011 event, several left-leaning governments
have proposed reducing reliance on nuclear power to 50% over the coming
decades. But many conservatives see nuclear energy both as core to the
nation’s environmental policies and to its economic output, because
France is a leader in the nuclear field.
Indeed, state-owned EDF has built and maintained reactors throughout the
world. Today, it is involved in major projects in China, Finland,
Belgium, and the UK. Though no evidence has yet surfaced publicly, its
not illogical to think that because the common sources of these
components, and thus the common sources for their problems—Le Creusot
and JCFC—have supplied or are supplying parts to facilities worldwide,
the carbon segregation problems could well spread beyond France.
For NPPs now under construction by EDF, either Le Creusot or JCFC forged
some of the casings almost a decade ago; it would be very costly and
time-consuming to replace them. Pierre-Franck Chevet (Figure 3), head of
the ASN, said that a similar AREVA forging technique had been used for
five other EPRs planned or being built. Two of these are in Taishan,
China, and two are set for Hinkley Point C. Components have also been
manufactured for one planned EPR at Calvert Cliffs, Maryland.
Going further, ASN has also indicated that in the nuclear components
supply chain, three examples of Counterfeit, Fraudulent and Substandard
Items (CFSIs) surfaced in 2015. No word yet if more CFSIs have been
found since, or who was responsible. But with inspectors now fanning out
across the French nuclear fleet, it’s likely that there will be more
revelations to come.
Erring on the Side of Safety?
Despite the outages and findings from the carbon quality investigations,
EDF continues to downplay the risk. “The safety margins are very large
and the carbon content does not undermine integrity or security, even in
the case of an accident,” an EDF spokesperson told Le Monde newspaper.
But questions about quality control practices at Le Creusot, which is at
the heart of this problem, continue to grow. Indeed, the greater the
scrutiny, the more problems are being discovered. The number of
components affected by irregularities and already installed in operating
NPPs increased from 33 known issues in April to 83 by the end of
September. Startlingly, irregularities affecting just the Flamanville
EPR project increased from two to 20 during the period.
While EDF and AREVA are dealing with costly damage control, ASN and
other agencies are assuming their watchdog positions. Indeed, the ASN
representative said, “We take no risks. That is the rule. If we don’t
know the dangers of the carbon segregation, then we must take the
reactors offline until we know what the situation is and [can confirm
that] it’s not dangerous.
“There are questions about document files—and now from tests—where we
have noticed that there is potentially more segregation. So taking the
reactors offline is a precaution. We have to have assurances that this
is not a safety matter, that is why so many reactors are now offline,”
said the ASN insider.
ASN revealed that AREVA has now identified at least 87 irregularities
concerning EDF reactors in operation, including vessels, steam
generators, and main primary system piping, plus the 20 issues for parts
intended for Flamanville 3, and one more affecting a steam generator
planned for installation in Gravelines 5. Inspectors have also found
four irregularities affecting transport packaging for activated
substances. ASN said that whatever the outcome of these investigations,
the irregularities “reveal unacceptable practices.”
The steam generators in question are heat exchangers between the water
circulating in the reactor’s primary coolant circuit—at a temperature of
about 350C and a pressure of 155 bar—and the water in the secondary
circuit that supplies steam to the turbines. Their domed lower head
(Figure 4) is part of the primary circuit and, therefore, has an
important safety role in ensuring cooling water is always available to
the reactor. There are three steam generators in the 900-MW pressurized
water reactor plants, like Fessenheim 2 and Bugey 4, while the larger
reactor designs feature four.
In July, ASN suspended the serviceability certificate for one of three
steam generators at Fessenheim 2, due to anomalies in the steel of its
lower shell. AREVA said the internal production record for the part
revealed a “divergence from the nuclear pressure equipment manufacturing
standards.” ASN also warned in June that certain steam generator channel
heads at the reactors could contain a zone comprising a high carbon
concentration, which could weaken the mechanical resilience of the steel
and its ability to resist the spreading of cracks.
External Parties Push for Answers
As previously noted, the current crisis roiling France’s reactor fleet
has its origins in 2014 with the discovery at the under-construction
Flamanville 3 plant of several anomalies in the composition of steel in
certain zones of the vessel closure head and the vessel bottom head of
the EPR reactor. This led to an internal audit, released in April 2015,
suggesting the existence of many more anomalies.
Though these anomalies were initially downplayed by ASN and AREVA,
critics continued to push for a more stringent investigation. In
September 2015, the release of an independent evaluation conducted by
Large and Associates—a UK-based engineering firm—at the request of
Greenpeace France really blew the doors open.
“The nature of the flaw in the steel, an excess of carbon, reduces steel
toughness and renders the components vulnerable to fast fracture,” said
the report’s author, John Large. The Greenpeace report, “Amplified the
questions ASN already had,” said the ASN representative who spoke with
POWER.
Of the 12 NPPs identified by ASN to have carbon problems, each had their
replacement steam generators forged by JCFC. According to technical
reports, their components—including the bottom channel heads, certain
tube-sheets, and some top elliptical domes—were believed to contain
zones of macrosegregation, possibly with enhanced carbon content.
Initial EDF analysis found a maximum excess carbon content of 0.3%—about
50% more than the design specification of 0.22%.
“On this basis, independent adviser, Institut de Radioprotection et de
Süreté [Nucléaire] (IRSN) reckoned that the risk of catastrophic failure
and fuel melt could be mitigated if certain further additional
conditions and ‘compensatory’ measures were implemented until a
scheduled outage would enable further examination of the JCFC
components,” wrote Large in the Greenpeace report.
But initial surface tests were followed by more invasive studies. The
first NPPs to enter scheduled refueling outages for a more thorough
examination were Tricastin 1 and 3. The early nondestructive inspection
results for the JCFC bottom channel heads at these NPPs revealed an
alarming 0.39% level of carbon present, almost 100% greater than the
maximum permissible level. That finding, with its associated reduction
in material toughness, rendered the component vulnerable to fast
fracture, reported Greenpeace in a late October update. IRSN revised its
analysis on October 18 and advised ASN to order the shutdown of all but
one of the NPPs with JCFC steam generator components installed. These
shutdowns are to remain in force until EDF can demonstrate that the
individual NPPs are once again deemed safe to reenter service.
ASN’s earlier concerns were backed up by IRSN. It likewise rejected
assurances given by both EDF and AREVA that there was no safety risk
from any steam generators containing the excess carbon flaw. As far back
as August, IRSN warned ASN that EDF’s submission was incomplete; there
was a risk of abrupt rupture, which could lead to a reactor core fuel
melt; and immediate compensatory measures were needed to safeguard the
operational NPPs involved.
Uncertainty Remains
At a French parliamentary hearing into the situation on October 25,
Chevet said that his agency would need another year or two to examine
thousands of more pages in its investigation of reporting irregularities
at AREVA’s Le Creusot foundry. “We will likely find more anomalies and
irregularities,” said Chevet.
As of late October 2016, POWER’s source at ASN has confirmed the following:
Six affected NPPs have been granted approval to restart and are
operating normally. They are: Blayais 1, Chinon 1 and 2, Dampierre 2 and
4, and Saint-Laurent-des-Eaux B2.
Seven NPPs are in planned outages and have been, or are being,
inspected. They are: Bugey 4, Civaux 2, Dampierre 3, Gravelines 2,
Saint-Laurent-des-Eaux B1, and Tricastin 1 and 3.
Five NPPs have been ordered by ASN to be taken offline to conduct
checks before January 18, 2017. They are: Civaux 1, Fessenheim 1,
Gravelines 4, and Tricastin 2 and 4.
Three NPPs are currently scheduled to remain unavailable throughout
the winter months. They are: Bugey 5, Gravelines 5, and Paluel 2.
One NPP has been ordered by ASN to shut down following the
detection of an irregularity in the lower shell of the steam generator.
That unit is Fessenheim 2.
Incidentally, Paluel 2 has been offline since May 2015. Its maintenance
period is continuing, following an incident on March 31, 2016, in which
a 465-ton steam generator tipped over during removal (Figure 5).
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