Courtesy of csy2k--Non HFSA
:~O
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Hmmm. Cascading power outages, nuclear core damage, significant international
failures, no contingency plans.
Full presentation at:
nrc.gov
excerpts of Dr. Jackson's presentation follow:
Dr. Shirley Ann Jackson, Chairman
U.S. Nuclear Regulatory Commission
OECD/NEA Committee on Nuclear Regulatory Activities
International Workshop on the Impact of the Year 2000 on the Nuclear Industry
Ottawa, Canada, February 9, 1999
The Y2K problem has significant implications for the management of electrical
distribution networks (grids). Individual susceptibilities may exist in software
controlling a particular portion of the grid itself or telecommunications
systems supporting grid management. Moving downward to the electrical generation
level, Y2K problems can affect individual components involved in the production
of electricity, such as digital process controllers. When one considers a
nuclear power plant, a concern exists that not only power generation problems
may arise, but that problems may extend to the safety systems of a facility and
create challenges to these systems.
When one considers the myriad of possible situations in which the Y2K problem
can manifest itself, it soon becomes obvious why the issue demands our prompt
attention. In an admittedly pessimistic scenario, what starts as a Y2K-related
electrical grid instability, for a particular nuclear plant, could cascade into
a loss of offsite power which, in turn, would challenge plant safety systems.
Can such a cascade occur? In 1996, two electrical disturbances (within a
five-week period) on the Western U.S. Grid caused 190 plants to trip off-line,
including several nuclear units. In particular, on July 2, 1996, a transmission
line sagged into a tree in Idaho, creating a ground fault which progressed into
a major fault on the Western Interconnection. The affected nuclear plants saw a
frequency transient, but did not scram or lose offsite power. A similar event
occurred the next day but did not propagate outside Idaho. On August 10, 1996,
again a line sagged into a tree, this time in Oregon. The subsequent transient
resulted in the loss of over 30,000 MW(e) of load, 25,000 MW(e) of generation,
which is 17 percent of the total western U.S.-Canada generation. Among the 190
generating units that tripped were 4 nuclear units at Diablo Canyon in
California and Palo Verde in Arizona.
Why are these events significant? Let me explain. First, such cascading
transients, in causing reactor scrams, can challenge plant safety systems
directly. Second, they can lead to Station Blackout events. In 1988, the NRC
initiated Individual Plant Examinations to study the various initiators of
reactor core damage events. All U.S. nuclear plants performed probabilistic risk
assessments, with detailed modeling of their plant systems, to search for
plant-specific vulnerabilities from severe accidents. At many of the nuclear
plants these studies showed that a major contributor to core damage frequency
was a Station Blackout event. Events of this type are defined as
Loss-of-Offsite-Power events, coupled with the inability of the onsite emergency
diesel generators to provide power to key plant safety equipment. If a cascading
transient brought down multiple generating units at a time that onsite power
sources did not exist, or were compromised, a nuclear plant could experience a
Station Blackout event.
Depending upon the degree of Y2K readiness in safety systems, the result of a
Loss of Offsite Power or Station Blackout could range from an analyzed,
expected, plant response to a more significant event. Moreover, if emergency
response is required offsite, the degree to which the telecommunications
infrastructure is Y2K compliant would dictate the effectiveness of that
response. To be sure, we at the NRC do not deem such an outbreak of failures to
be probable based upon what we currently know about Y2K. Rather, it is the
possibility of such events that motivates our actions.
-----
The President's Council stated, in its first quarterly report, that
international failures are likely. Despite recent increased efforts, a number of
countries have done little thus far to remediate critical systems. These
failures could have a significant impact upon the U.S. and other countries,
especially in areas that rely heavily upon cross-border operations.
International Y2K activity is the area about which we have the least
information. The U.S. State Department and other agencies on the Council's
International Relations Working Group have been working with U.S. embassies and
other organizations around the world in an effort to gather Y2K information on a
country-by-country basis.
-----
In the international arena, my understanding is that the nuclear power industry
and its regulators in Canada, Western Europe, and the Far East have undertaken
similar efforts and readiness schedules to that of the NRC for addressing the
Y2K problem at nuclear power plants. However, some countries have started only
recently to focus on the Y2K problem. Last month, at a meeting of the
International Nuclear Regulators Association (INRA), which I chair, a statement
was drafted on the Y2K problem, expressing concern that the results of the
recent United Nations Conference indicated that few countries will be Y2K ready,
and that few have adopted expert guidance regarding remediation and contingency
planning. Contingency planning, while important in itself to all countries,
takes on new importance in late-starting countries, due to the short time
remaining before the year 2000. In its statement, the INRA urged governments and
their regulatory authorities to take urgent action to diagnose the extent of the
Y2K problem in nuclear facilities (including nuclear power plants, fuel cycle
facilities, and medical facilities), and to formulate and implement effective
remediation programs and contingency planning in the near term for this
pre-eminent concern. I understand that contingency planning was the subject of
discussion at a session here today. This is a key aspect to effective Y2K
readiness.
-----
We have come to recognize that nuclear power plants are not islands. The plants
rely upon stable electrical distribution systems to support steady-state
operations. Symbiotically, stable distribution systems rely on the collective
output of generating facilities. In a very real sense then, we all are dependent
on the stability of one another. An extension of this concept applies to
emergency planning. The ability of both onsite personnel and civic responders to
act will be tied directly to the state of Y2K preparedness in each of the
participating organizations. In the same way that each generating plant on a
grid can be affected by the other plants on the grid, the emergency response
capabilities associated with one plant can be impacted in responding to other
potential eventualities, such as events at neighboring plants or other
Y2K-related emergencies outside of the electricity industry. For this reason,
ensuring continuity at the interfaces of regulator-to-licensee,
regulator-to-public, and regulator-to-government is crucial, as such continuity
is required to buttress emergency response, our last line of defense in
protecting public health and safety. It is the recognition of these facts that
has driven many of the actions I have described tonight--the recognition that,
despite our best efforts, something still could go awry. I might point out that,
just within the past several weeks, at the initiative of the NRC, the NEA
Committee on Nuclear Regulatory Activities (CNRA) and its member countries are
planning an international exercise to assist in world-wide contingency planning.
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