Monday, February 11, 2013

Backgrounder - Study shows severe nuclear accident at Point Lepreau 40 times more likely than previously thought


February 5, 2013.
On Friday January 18 2013 NB Power released the preliminary results of a study that showed
that NB Power has grossly underestimated earthquake risk. The Canadian Nuclear Safety Commission
(CNSC) ordered a new site specific seismic hazard study be completed as a result of CCNB Action’s
intervention at the licensing hearings for Point Lepreau on Dec 2 2011. The preliminary results show that
the probability of a severe accident with a large release of radiation to the public is more than 40 times
greater than NB Power’s first submission to the CNSC and is 4 times greater than internationally
accepted safety goals.  This shows that Lepreau went from being the safest reactor in North America vis
a vis earthquakes , to one of the most dangerous
i
.
The Point Lepreau nuclear generating station’s ability to withstand earthquakes has been a topic
of controversy ever since it was built, when the lead seismic engineer resigned over the issue. This

seismic uncertainty, as well as numerous other safety issues, has been a topic of concern in CCNB
Action’s interventions for quite some time now.  Following is a timeline of the issues surrounding the
seismic readiness of Point Lepreau.
Point Lepreau Seismic Timeline
1975-Ramzi Ferahian, lead civil engineer for Lepreau resigns because of safety and calculation concerns
ii
.
1982-Ramzi Ferahian, providing testimony to the Energy Select committee of MLA’s, states “the
seismicity of the Point Lepreau area is being downplayed by regulatory and licensing agencies”. When
asked if he would locate a nuclear power plant at Point Lepreau he stated that he “would not because of
the region’s history of seismicity”
iii
1994-The attorney general commissioned a seismic hazard study as expert witness for legal proceedings
with Energy Probe
iv
. The results of this study showed that Point Lepreau was compliant with the
standards at that time which was an earthquake with a probability of 1 in 1000 years. This is less than
half of what the National Building Code now requires for all structures ( 1 in 2475 yrs). New requirements
for nuclear installations say that they must be able to withstand an earthquake with a probability of 1 in
10,000 years. The new study shows that the earthquake Point Lepreau is now able to withstand is only 1
in 2700 years.
2002-NB Power starts to prepare the methodology for its Seismic Margin Analysis. This was the first of
its kind in Canada
v
.
2004-The CNSC has concerns about NB Power’s Seismic Margin Analysis methodology
vi
.2006-The CNSC accepts the seismic margin analysis but puts a condition that NB Power must provide
confidence that the contribution of seismic events to the Probabilistic safety analysis is low and that NB
Power meets its probabilistic safety goals of 1 in 10,000 years probability of core meltdown and 1 in
100,000 years probability of a large release of radiation
vii
.
2007-NB Power submits a technical assessment to the CNSC stating that both the core meltdown
probability and large release of radiation probability is lower than 1 in a million years
viii
.
Sometime between 2007 and 2011-The CNSC has NB Power’s technical assessment industry peer
reviewed and it was found that “industry review of the methodology used raised some uncertainty of
the results of the expected risks”
ix
July 8, 2011-NB Power resubmits another technical assessment to the CNSC using a new internationally
accepted calculation. The results showed that the core meltdown probability was 1 in 19,493 years and
a large release of radiation probability was 1 in 196,078 years
x
.
Dec 1 and Dec 2 2011-CCNB Action presents evidence that the seismic hazard curves used from the 1984
study in the technical assessment were outdated. This included the fact that the 1994 study from the
attorney general showed they were underestimating the risk, as did the National Building Code. CCNB
Action also presented to the CNSC that some of the calculations were done incorrectly
xi
.
Dec 8 2011-CCNB Action has NB Power’s submission to the CNSC peer reviewed by Bob Kennedy from
RPK Structural Mechanics in California, the author of the calculation used in the technical assessment.
He confirms that part of the calculation was not done correctly and that it was un-conservative
xii
.
January 30, 2012- NB Power resubmits results from the technical assessment doing the calculation
properly this time but still using the outdated 1984 data. The updated results showed that the core
meltdown probability was now 1 in 17,559 years and large release frequency was now 1 in 143,864
years
xiii
.
-February 16 2012- The CNSC grants a license to NB Power which includes acceptance of the License
Condition Handbook as presented by the CNSC staff during the hearings. The handbook, at the time of
the hearings stated that NB Power had to be compliant with its probabilistic safety goals. At CCNB
Action’s request
xiv
, the CNSC also required Point Lepreau to undergo a site specific seismic hazard study.
-August 15 2012 CCNB Action intervenes in the CNSC’s annual public meeting and gives evidence that
the CNSC staff changed Point Lepreau’s license condition handbook without notifying the commission.
Now, instead of having to be “Compliant with its probabilistic safety goals, they are only required to
compare the results to the probabilistic safety goals
xv
.
-January 18 2013- NB Power releases the preliminary results of the site specific seismic hazard analysis.
Using the new results, CCNB Action calculates that the new core meltdown annual probability is 1 in 7,825 years, only 78% of its safety goals. Its large release annual probability is 1 in 25,641 years; around
40 times NB Power’s first submission, and only 25% of its safety goals. The annual probability of a core
meltdown is now very similar to the annual probability of dying in a car crash (1 in 6,197 years
xvi
).
    Furthermore, CCNB Action recently uncovered that NB Power uses a median seismic hazard curve
instead of a mean seismic hazard curve. Using a mean curve shows an increase in seismic risk. Our
research has shown that CSA standards for nuclear reactors in Canada require the use of mean seismic
hazard curves
xvii
, and that all other reactors in Canada have used a mean seismic hazard curve in their
studies
xviii
. Bob Kennedy the author of the calculation used by NB Power states in a research report to
the CNSC that “Mean risk incorporates consideration of both epistemic uncertainty as well as aleatory
(random) variability, whereas median risk does not fully address epistemic uncertainty. In the case of
seismic risk, mean and median risk estimates commonly differ by a factor of three to ten. I recommend
that RD-337 clearly define the quantitative safety goals to be mean risk goals.”
xix
As well, all of the other
seismic margin analyses that we reviewed used mean seismic hazard curves. We are perplexed as to
why NB Power’s summary of the preliminary results still indicate they will be using the median seismic
hazard curve. In a meeting with CCNB Action, before the report was published, NB Power stated that a
mean hazard curve would be used. If international safety goals are going to be used, they are
meaningless if they are not calculated the same way as everyone else..
    Natural Resources Canada and Ken Burke, the seismologist who has done much of the seismicity work
for NB Power, have both stated that the next significant earthquake will likely be in the Passamaquoddy
Bay area near Point Lepreau
xx
. CCNB Action believes that Lepreau needs to be shut down immediately
before an accident happens. The Fukushima accident has shown us that ignoring science and the
mentality that “it’s safe enough” can prove disastrous.
We think that the New Brunswick government should take advantage of the readily available
and cheap purchased power for 4 c/Kwh
xxi
. The risks of nuclear power are way too high and the benefits
way too low. This should worry anyone from big business owners to local residents, as none of our
insurance policies cover nuclear accidents.   The risk of losing everything just to have electricity
generated more expensively than it can be purchased elsewhere is unsustainable and irresponsible.
We urge the CNSC and NB Power to accept that mistakes have been made.  We do not believe it
is moral to continue to allow a reactor to run when science shows that it is not safe. If Lepreau is
allowed to continue to run, there have been no lessons learned from Fukushima, and our safety will be
compromised.Comparison Of Results
Seismic Core
Damage
Probability
Seismic Large
Release Probability
Total Core
Damage
Probability
Total Large Release
Probability
NB Power 2007 Submission 1,000,000 1,000,000
NB Power July 2011
Submission
90,909 222,000 19,493 196,078
NB Power January 2012
Submission
60,060 157,480 17,559 143,864
2010 Nation Building Code
Median Hazard Curve
33,333 64,516 14,225 62,108
New Study Median Hazard
Curve
28,571 66,667 13,280 64,098
2010 Nation Building Code
Mean Hazard Curve
19,417 35,088 10,893 34,363
New Study Mean Hazard
Curve
11,429 25,641 7,825 25,252
                                                       
i
http://www.nbcnews.com/id/44369172/ns/us_news-environment/t/earthquake-threat-nuclear-reactors-farhigher-realized/
ii
Letter by Ramzi Ferahian in Daily Gleaner June 12, 1979
iii
Kings County Record 1982
iv
Natural Resources Canada Open File 2929
v
NB Power Summary of Preliminary results of site specific seismic hazard study
vi
2004-05-27_PSA mtg Mar 23 2004
vii
August 16 2006 87RF-00521-130-000
viii
April 10 2007 87RF-00521-130-000
ix
0087-03612-3001-001-TA-A-01-0000
x
2011-07-08 Impact Assessment of Updated Seismic Hazard Information for Eastern Canada and Seismic Risk
Estimation for Point Lepreau
xi
2011-12-01 and 2011-12-02-Transcription-Hearing
xii
RPK-111208.1 Comments on Estimation of Seismic Risk for PLGS Robert P. Kennedy December 8, 2011
xiii
0087-03612-3001-001-TA-A-02-0000
xiv
2011-12-01-Decision-NBPower-e-Edocs3881211-Final
xv
Supplemental Submission from CCNB Action for Aug 15, 2012 meeting                                                                
xvi
http://www.medicine.ox.ac.uk/bandolier/booth/Risk/trasnsportpop.html
xvii
CSA Standard N289.2 “Ground Motion Determination for seismic qualifications of nuclear powerplants
xviii
Gentilly 2 PSA base SMA Methodology
xix
RSP-0255 Independent Review of Staff Review Guides Related to Engineering Aspects of Protections Against
Malevolent Acts, Seismic Hazard, External Hazards Other Than Seismic, and Internal Hazards, R. P. Kennedy,
Structural Mechanics Consulting
xx
2011-12-01 and 2011-12-02-Transcription-Hearing
xxi
http://www.theglobeandmail.com/news/national/hydro-quebec-told-former-liberal-government-beforeelection-to-shut-down-costly-gentilly-ii-project/article7992655/

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