San Onofre Unit 2 Replacement Steam Generators Incomplete and Inadequate Tube Inspections
San Diego, CA (November 9, 2012) – The failure of eight Replacement Steam Generator (RSG) tubes (something which has never
happened before) plus the structural integrity of thousands of additional damaged
tubes in both SONGS Units 2 and 3 RSG’s are now in question and affect the
safety of about 8 million Southern Californians. This design failure, which has been termed by the
NRC as “a very serious safety issue”
because of the unprecedented tube damage: Unit
3
has 807 tubes plugged and Unit 2 has
510 tubes plugged – which makes them the 2
WORST RSG’s in the history of the entire
U.S. Nuclear “Fleet”. Which means that SCE was operating beyond
their Current License Basis (CLB) and Safety Analysis Limits, plus SCE
has yet to be penalized by the NRC for these violations, as required by law. These RSG failures also offers real proof for
the very first time, that if a Main Steam Line Break accident had occurred, at
least eight RSG tubes would have leaked/ruptured and potentially caused the
SONGS Unit 3 reactor to become a nuclear disaster (e.g., like Fukushima,
Chernobyl or Three Mile Island) due to the loss of undetermined amount of
radioactive core coolant!
The truth is that San Onofre escaped
becoming an International Nuclear Events
Scale (INES) Level 7 nuclear disaster by the slightest of margins,
unlike Fukushima!
SONGS Reactor Compatibility
Experiment (RCE) States, “Visual inspection of the tube sheet primary
side of the SG 3E088, with the secondary side pressurized, identified the tube
with the leak. Subsequent Eddy Current
Testing (ECT) inspection identified extensive unexpected tube free-span
wear at
the leakage location, not typically
seen in recirculating SGs, and tube-to-support wear. A full-length ECT inspection of each tube
(100%) in all four SGs using a bobbin coil probe was performed and provided a
comprehensive extent of condition evaluation for tube free-span and
tube-to-support wear. The bobbin coil probe inspection was supplemented by
Rotating Coil (+Point) probe inspection, which provided further confirmation of
the extent of condition. This
supplemental rotating probe examination covered the U-bend portion of
approximately 1300 tubes in each SG.”
Thousands of Unit 2 Steam generator tubes, Anti-vibration Bars and Tube
support Plates have suffered extensive wear and undetermined amount of internal
cracking during 22 months from flow-induced random vibrations and/or cyclic fatigue. In
addition, SCE has only performed remote visual inspection of 8% of the tubes in
their damaged Unit 2 RSG’s plus this does include inspection of any tube
support plates for any visible damage, structural deformation, cracks and/or any other abnormalities.
The methods employed by SONGS using bobbin and
rotating coil (+Point) probes to inspect the Unit 2 damaged
tubes cannot reliably determine the depth, extent and location of these cracks,
so
the actual condition of the tubes remains a dangerous unknown! In a Rush to Restart Unit 2 and cut their costs, Edison has not inspected
more than 2000 Unit 2 Steam Generator tubes with T/R single-pass array probes, laser-scanned
penetrant inspection and ultrasonic detection technologies to accurately identify and determine the depth, extent and
location of these internal cracks at the U-bends and
tube-support intersections. NRC's
regulations do not allow SONGS to start up with any steam generator tube
cracked more than 35% of its wall thickness. Therefore by not performing these accurate inspections, Edison has not met the performance
criteria specified in 10 CFR Part 50, Appendix A, “General
Design Criteria for Nuclear Power Plants,” Criterion 14, 15, 30 and 32, which establishes the fundamental regulatory
requirements for the integrity of the SG tubes.
The DAB Safety Team has concluded that SONGS Unit 2
Replacement Steam Generators (RSG) are in worse shape now than certified by SCE
and their three NEI Qualified, “U.S. Nuclear Plant Designers.” The accident scenario of concern consists of
two events: (1) a non-isolable secondary system break or rupture that is
outside containment; and (2) a coupling of this break with the rupture of, or
significantly increased leakage from, affected SG tubes. Even at 70% power operations, if a steam line
break outside containment were to occur in Unit 2, the depressurization of the
steam generators with the failure of a main steam isolation valve to close
would result in 100% void fraction in the degraded U-Tube bundle and the straight leg portion between the Tube
Support Plates. This condition of ZERO
Water in the steam generators would cause fluid elastic instability (FEI) and
flow-induced random vibrations, which would then result in massive cascading SG
tube failures, involving hundreds of degraded active SG tubes. Fluid elastic
instability (FEI) and flow-induced random vibrations can progress through a
buffer zone of plugged tubes to reach pressurized, in-service tubes and create
additional SG tube failures. The
resulting SG secondary side blow-down could further increase tube leakage due to
resonance vibrations within the affected SG tube bundle. With an undetermined amount of simultaneous
tube leaks/ruptures, approximately 60 tons of very hot high-pressure
radioactive reactor coolant would leak into the secondary system. The release of this amount of radioactive
primary coolant, along with an additional approximately 200 tons of steam in
the first five minutes from a broken steam line would EXCEED the SONGS NRC
approved safety margins. So, in
essence, the RSG’s will become loaded guns, or a nuclear accident waiting to
happen. Any failure under these
conditions, would allow significant amounts of radiation to escape to the
atmosphere and a major nuclear accident would easily result causing much wider
radiological consequences and even a potential nuclear meltdown of the
reactor! Since these events would happen
at an extremely fast pace, no credit is assumed in the first 5 minutes of the
main steam line break accident for: (1) Enhanced Unit 2 Defense-In-Depth
Actions - SCE Restart Plan Enclosure 2, Item 9.0, and (2) The differential
pressure across the SG tubes necessary to cause a rupture will not occur if
operators prevent RCS re-pressurization in accordance with their Emergency
Operating Procedures - Enhanced Unit 2 Defense-In-Depth Actions - SCE Restart
Plan Enclosure 2, Item 5.2,2, Probabilistic Risk analysis.
In
Emergency Planning Space, decisions have to be Accurate and Timely.
Under-conservative, rushed and profit-motivated analyses based on limited
facts, biased and ambiguous operational data, untested deterministic and
probabilistic risk analysis, conflicting theories and differing operational
assessments of degraded equipment at even reduced power operations for 150 days
with conditional monitoring along with unproven and unreliable compensatory
actions represent enormous risks to public safety, the environment and our
nation’s economy.
The NRC must REALLY resolve the concerns stated above as soon as possible. In
the interim, the NRC must stop making favorable decisions to SCE (especially
when it lacks defensible technical and inspection bases), which affect the
lives of millions of Southern Californians."
The above analysis is consistent
with the conclusions and reports provided earlier on this subject by:
1.
Fairewinds
Associates Internationally Known Nuclear Consultant Arnie Gundersen and his
team of Anonymous Industry insiders, who have had lengthy careers in the design,
fabrication, and operation of nuclear steam generators.
2.
Professor
Daniel Hirsch and Internationally Known Nuclear Consultant Dale Bridenbaugh.
3.
Dr.
Joram Hopenfeld, a retired engineer from the Office of Nuclear Regulatory
Research and NRC's Advisory Committee on Reactor Safeguards (ACRS) report
issued in February 2001, which substantiated many of Dr. Hopenfeld's concerns,
CPUC: California Public Utilities Commission
DBA: Design Basis Accident
ECT: Eddy Current Testing
FEI: Fluid Elastic Instability
MHI: Mitsubishi Heavy Industry
MSLB: Main Steam Line Break
NRC: Nuclear Regulatory
Commission
RCE: Reactor Compatibility
Experiment
SCE: Southern California
Edison
TTW: Tube-to-Tube Wear
DAB Safety Team
Media Contact: Don Leichtling (619) 296-9928 or Ace Hoffman (760) 720-7261
Don Leichtling and Ace Hoffman are the spokesmen of the DAB Safety Team, who along with the support of an ever-growing number of SONGS Concerned Insiders and Whistleblowers have prepared the following analysis.
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Copyright
November 9, 2012 by The DAB Safety Team. All rights reserved. This material may
not be published, broadcast or redistributed without crediting the DAB Safety
Team. The contents cannot be altered without the Written Permission of the DAB
Safety Team Leader and or the DAB Safety Team’s Attorneys.
