Darlington: The Safety Elephant in the Room

Fukushima has changed our approach to nuclear safety to more emphasis on accident mitigation.

At these hearings the elephant in the room was not Elmer the traffic safety elephant well know to Canadian children but the Fukushima safety elephant. It shook up the way we look at nuclear safety.
The essential lesson from Fukushima is that future reactor accidents are much more probable than what we might like to think. Since then accident mitigation has become an urgent consideration as shown by the emphasis on emergency planning at the hearings.
According to the World Nuclear Association there have been almost 15,000 years of power reactor operation from about 1960 to the end of 2012. During that time there have been three serious nuclear accidents – “black swans” (Three Mile Island, Chernobyl, and Fukushima). This makes the probability of a serious accident about 1 in 5,000 or 2 x 10-4 per reactor year. One can play with this number by changing the number of reactors that melted down (three at Fukushima or not counting TMI as a serious accident) and so on but it’s the order of magnitude of the meltdown probability that is really of interest.
Each of these events occurred in a different reactor types (PWR, RMBK and BWR) in countries with differing nuclear cultures and regulation regimes. Aside from stressing the importance of overriding issues such as human error, institutional failure and design defects, it is difficult to know where to go with the black swan approach in analyzing reactor safety. Although certainly one can draw lessons from them after the fact as is being done for Fukushima, notably compensating measures for the complete loss of electrical power in a reactor plant (“total station blackout”) and further measures to prevent hydrogen explosions.
Contrast this with the traditional approach to reactor safety known as PSA (Probabilistic Safety Analysis/Assessment). This approach tries to examine all possible accident event sequences and figure out the probability associated with each sequence. In practice it’s very complicated and there can be hundreds or even thousands of events and sequences. To give an overly simplified example, let’s consider an accident sequence that starts with event A: a cooling pipe breaks, then B: a sensor fails to indicate the break, then C: the reactor operator doesn’t see the reactor temperature increasing, then D: a switch activating the emergency core cooling system doesn’t work, then E: the operator pushes the wrong button to correct this and F: a core meltdown occurs because the reactor overheats.
This too simple example illustrates some of the key aspects of PSA. The validity of the approach depends on the accuracy of the probabilities assigned to the individual events since the overall accident probability (of event F for example) is obtained by multiplying the probabilities of the individual events in the sequence. Some might be well known; perhaps the B sensor is used in many applications and its failure rate is well documented from experience. At the other end of the scale there are probabilities that one can merely guess at e.g. the initiating pipe break probability might be hard to evaluate. Another very important condition is that the probability of a certain event happening is independent of other events. This may not always be the case: event C implies an incompetent operator and therefore, event E may be more likely. For completeness all possible accident sequences need to be evaluated. There isn’t any way to be sure completeness has been achieved. Unfortunately, there wasn’t an event sequence at Fukushima that started with: “suppose there was a tsunami wave higher than the protective sea wall”.
Safety analysts in Canada and internationally continue to use PSA. In fact people have made whole careers in the nuclear industry putting bells and whistles on the basic PSA framework. While it has proven useless for predicting accident probabilities, PSA is useful for highlighting and correcting potential problems. In the context of the example above, perhaps a more reliable type of switch D could be installed or better training is needed for operators in terms of events C and E. The other important reason for continuing PSA is that there doesn’t seem to be any worthwhile alternative. As CNSC staff pointed out, PSA is still the international standard approach to reactor safety.
The problem is that PSA comes up with accident probabilities of the order of one in a hundred thousand or one in a million or even one in ten million per reactor year that are completely out of whack with the one in five thousand observed accident frequency. At the hearings I was disappointed to hear staff from the CNSC and OPG bandy about terms such as a “10-6 accident”, usually without the “per reactor year” unit giving the erroneous implication that these were realistic accident probabilities. In the best interpretation this could be excused as bad communications using nuclear jargon and in the worst interpretation a dishonest attempt to minimize the probability of an accident.
Much more serious was OPG and the CNSC using PSA as a basis for emergency planning. Statements were made that can be roughly paraphrased as “their (PSA) probability is so low that we don’t consider accidents with offsite consequences more than a few kilometers from the site” and “OPG has identified two catastrophic accident scenarios but their PSA probabilities are in the order of 10-7 and so we can safely ignore them”. Using PSA, discredited by experience as a method of predicting accident probabilities, is unscientific and intellectually dishonest. Thus, in my opinion, the hearings witnessed a disgraceful performance on the part of the institutions charged with our nuclear safety.

Darlington: CNSC Independence?

Several intervenors at the Darlington hearings expressed views that the CNSC was biased toward the nuclear industry. On the few occasions when he elected to acknowledge these claims the President, Michael Binder, countered by harrumphing “prove it”. With all the cards stacked in its favour I feel the onus should be on the CNSC to prove its independence rather than the other way round since its credibility is its most precious possession.
Any regulatory system always faces the difficult problem of the close relationship of the regulated and the regulators. A kind of Stockholm Syndrome comes into play which some called “regulatory capture” (There was a guy from Greenpeace who seemed so much a part of the current and past proceedings that he may be evidence of “intervenor capture” ) This perception is compounded by the federal government’s cost recovery program whereby OPG pays CNSC to be regulated. It seems that about 70% of the CNSC budget is obtained from the regulated. Similarly the location of many CNSC staff at OPG sites including Darlington increases the perception of a too close relationship. It was admitted that there was no personnel rotation system to prevent CNSC staff from being “captured” by OPG. Some of the high paying jobs at Darlington referred to by boosters are in fact CNSC jobs.
Speaking of jobs the CNSC now seems to have a staff numbering about 850; this is double the 1999 staffing level of 425. It’s difficult to see how the CNSC can justify doubling its staff in a decade of declining nuclear activity or is it just a symptom of empire building?
Even the format of the hearings leads to an impression of bias. The CNSC members sit at a long table as a tribunal with the applicants, in this case OPG, on one side before them with Commission staff on the other. Those who come to give their views to the Commission, the intervenors, are placed in a position between OPG and CNSC staff. It’s almost as if the intervenor is the “accused” in a trial. Several intervenors admitted to being nervous and feeling intimidated by this arrangement. On the plus side, there was often applause from the audience in support of their presentations.
The nature of the hearings is such that CNSC staff and OPG almost always tag teamed to reply to the comments of the intervenors because both sides have agreed on the issues raised in various documents negotiated beforehand. Similarly, what can be discussed and what can’t be (i.e. the scope of the hearings) was predetermined by OPG and the CNSC and often as Inspector Clouseau would say “the old beyond the scope ploy” was used to prevent certain subjects being raised. It was no wonder that Intervenors got the feeling they were being ganged up on by Commission staff taking the side of OPG.
At one point an intervenor directly challenged the CNSC’s distribution of literature promoting the nuclear industry. The President claimed that section 9b of the Nuclear Safety and Control Act of 1997 permitted the CNSC to do so. It’s worth quoting the section:
“[an object of the CNSC is] to disseminate objective scientific, technical and regulatory information to the public concerning the activities of the Commission and the effects, on the environment and on the health and safety of persons..”The crux of argument is not whether the CNSC can legally disseminate information but rather whether the promotional material is “objective” and “scientific”. No useful discussion of this point took place because the President simply deflected the issue via a legalistic argument based on 9b.
Another independence issue raised was that according to the biographies on the CNSC website it appears one Commissioner worked for OPG as recently as 2011. The perception of a potential conflict of interest was possible and in fact this was raised by at least two intervenors. Once again this was sidestepped by the President. While I’m not impugning the integrity of this particular individual, I would say that the “optics” was poor and in my opinion recusal would have been more appropriate for an OPG application.
Speaking of optics perhaps the CNSC should report to Parliament through the Minister of the Environment rather than the present arrangement of via the Minister of Natural Resources. That might help position the Commission as more independent in some minds particularly when under new legislation it can conduct full Environmental Assessments.
The cynical might say that the current President might be more disturbed by accusations of being perfectly objective rather than of being biased. The fate of his predecessor, Linda Keen, who apparently was too objective for the government, must always be on his mind. My impression is that the present incumbent doesn’t realize the Commission’s serious credibility problem and it’s a pity he doesn’t seem willing to do obvious things to fix it.

Darlington Boosters

“As a nuclear plant-hosting municipality, we have depended on it in terms of finance and employment…. Our village may have reaped benefits for 30 or 40 years. But if we lose our homeland in return, what’s the point?.. What a lowly, sad people we are to think that way…”
These are the words of Tatsuya Murakami, Mayor of Tokai Japan after the Fukushima accident. Tokai has twelve nuclear establishments and about eight thousand of its inhabitants depend on them for their livelihood. I’ve been to the Tokai area on five or six separate occasions before Fukushima and found it to be a pleasant and prosperous place. Murakami was a strong early booster of the nuclear industry but now is the leader of the Japanese municipalities trying to stop the restart of their shut-down reactors.
This is just a cautionary note because, as one might expect, there were several project boosting interventions at the Darlington hearings based on economic benefits to communities including lots of well paying jobs. The essential messages were that the proponents loved all things nuclear and especially the associated money which they insist must be kept flowing. They were right to say that thousands of new high quality jobs were bound to be created by the refurbishment project.
Politicians at all levels pushed this message as did reps of the nuclear unions and companies in the industry. There were even a couple of presentations from the newly fledged local university, one consisting of a lame plea from engineering students that they needed the jobs the project would create.
While it’s not within the mandate of the CNSC to consider job creation, we can be sure that this aspect is glowingly reported to what used to be called “the Centre” of the federal government (PCO or PMO?) as yet another triumph of the administration’s Economic Action Plan.
OPG was portrayed by many as a strong supporter of the communities around Darlington. Apparently this included lots of money in addition to briefings to local municipal councils. It seems that for many years the OPG cash fairy was flitting around sprinkling money on all sorts of no doubt worthy organizations; they in turn showed up to sing OPG’s praises at the hearings.
Support was also given by towns hosting other nuclear installations far from Darlington. Closer to home the Mayor of Clarington gave a fulsome endorsement to OPG including thanking them for providing funding so that their Council could hire consultants to review the OPG submission to the Environmental Assessment. He didn’t say but I’d guess that such a review might be done for something like $50,000 or less. I thought it was a pity that the municipality with an annual budget of more than $60 million (as far as I could tell on the net) couldn’t afford to do this with its own funds especially since as the Mayor said it was so important to the town. But then who could refuse the OPG cash fairy?
Let’s hope for all of our sakes that Darlington’s local politicians don’t find themselves in the future with the same regrets as the Mayor of Tokai.