Rekan,

Percaya nggak percaya, ternyata pada tahun 2003 ada kira-kira 40 peristiwa
(events) nuclear accident di US saja yang dilaporkan oleh NRC. Semoga menambah
khazanah wacana kita soal debat mengenai PLTN!

Salam,

Fabby Tumiwa



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published by WISE/NIRS Nuclear Monitor on May 28, 2004

"POWER UPRATES": BOOSTING MEGAWATTS AND ACCIDENT RISK


Nuclear power stations experienced more than 40 "events" over the past few years
as a result of utilities squeezing more power out of aging reactors. An
accelerated industry-wide "power uprate" program has resulted in numerous and
repeated reactor internal component failures generating loose parts which can
damage safety-related reactor components along the main steam line raising the
risk of a nuclear accident.

(610.5609) NIRS - What the nuclear industry claims as a source of cheap and easy
extra-megawatts is in fact a dangerous experiment in reducing operational and
design safety margins to boost profits. More worrisome, the Nuclear Regulatory
Commission (NRC) is doing little more than expediting its licensing process to
facilitate more and larger power boosts without fully understanding the risks.

Since 2000, there has been a sharp increase in the number of participating
reactors along with industry's reach for higher power output. The industry
conceived of these uprates as a way to increase power output on a range from
less than 2% to as much as 20% above the original licensed thermal power. This
is achieved primarily through loading the reactor with highly enriched uranium
fuel. Higher enriched fuel means more thermal energy thus more steam to drive
turbine generators for more electricity. The U.S. nuclear industry has captured
the equivalent of more than four additional 1000 megawatt electric (MWe) power
stations from uprates in 101 of the nation's 103 operating reactors. Encouraged
by the Bush Administration's National Energy Strategy, current industry plans
seek to boost reactor power levels by an additional 2,270 megawatts electric
over the next several years.

However, power boosts also mean more dynamic forces and accelerated neutron
bombardment attacking susceptible reactor internal components. "Catastrophic
failure," as one NRC official described, of steam dryer components at Exelon's
Quad Cities 1 and 2 nuclear power station in Illinois has shed new light on the
growing risks to public safety from reactor power boosting.

Quad Cities Unit 1 and 2 nuclear power station, both 762 MWe General Electric
Mark I Model 3 Boiling Water Reactors (BWR) with license amendments for 17.8%
extended power uprates, have had three such failures in steam dryer components.
In June 2002, after 90 days of uprated operation, Unit 2 experienced
fluctuations in its increased steam flow, reactor pressure and moisture
carryover to the steam line. After shutting down for inspection, Exelon
discovered that a cover plate on the steam dryer had broken loose and several
other pieces had been swept down and lodged in the main steam line. GE diagnosed
the "phenomenon" as high cycle fatigue and Exelon modified the steam dryer with
thicker plates and went back on line.

On June 11, 2003, after an additional 300 days into the extended power uprate,
Quad Cities 2 again shut down to inspect the steam dryer after noting the high
moisture carryover in the steam. The steam dryer inspection again revealed
extensive cracking, broken bracing and severed tie-bars. A "fix" was
re-engineered and Unit 2 went back on line at the boosted power level. In
October 2003, Quad Cities Unit 1 observed the same symptoms and shutdown on
November 11 to inspect. They not only discovered significant cracking but a 6.5
inch by 9 inch section of steel plate had broken off from the steam dryer hood
and disappeared into the steam line system. Signs of damage indicated that the
missing part or parts passed through a recirculation pump. Before restarting on
November 29, 2003, Exelon repaired broken components and engineered fixes but
had not come to a conclusion on whether the still missing parts impacted future
reactor operation or to retrieve the internalized debris.

Exelon's uprated Dresden Unit 2 has also discovered extensive cracking in its
steam dryer in October 2003. NRC staff has identified that the steam flows are
so great under these extended power uprates that replacement of old with new
steam dryers might not address the associated risk of reactor core damage from
future loose parts.

NRC is a willing and submissive partner to industry efforts to boost power
levels and profits. In a recent meeting before NRC's Advisory Committee on
Reactor Safeguards, the agency was admonished for not obtaining detailed steam
dryer engineering diagrams from General Electric. An incredulous committee
member described staff's presentation diagrams as of little more value than
"cartoons" and remarked that a more deliberate effort should be made to obtain
precise diagrams. Another member remarked "Don't we care about risk
significance?"

At the forefront of the fight against new power uprates is a challenge by New
England Coalition to a proposed 20% power uprate request for Entergy's 32-year
old Vermont Yankee nuclear power station. Like Quad Cities and Dresden, Vermont
Yankee is a GE Mark 1 Model 3 BWR as are Minnesota's Monticello and
Massachusetts's Pilgrim nuclear power stations. The fact that NRC recently
admitted that it is still trying to "get its arms around the problem" and the
risk to public health and safety is reason to halt new power boost applications
and revoke those in already in place.

Source and contact: Paul Gunter at NIRS pgunter@...



Fabby Tumiwa (Coordinator)
Working Group on Power Sector Restructuring (WGPSR)
Jl. Mampang Prapatan XI/23 Jakarta, 12790
Tel: +62-21-79196721/22 Fax: +62-21-7941577
Email: fabby@... Website: www.wgpsr.org

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