Ra­di­a­tion in­ci­dent shows a gap in nu­clear safety pro­ce­dures

Cape Breton Post - - OUR COMMUNITY -

OTTAWA (CP) — An in­ci­dent that ex­posed hun­dreds of work­ers at an On­tario power sta­tion to low lev­els of ra­di­a­tion has re­vealed an ap­par­ent gap in safety pro­ce­dures at Cana­dian nu­clear fa­cil­i­ties.

Of­fi­cials from Bruce Power told a pub­lic hear­ing Thurs­day they did not an­tic­i­pate or test for air­borne al­pha ra­dioac­tiv­ity in one of the re­ac­tors cur­rently be­ing re­fur­bished at the Bruce A nu­clear sta­tion on the shores of Lake Huron.

They said they’re al­ways on the look­out for beta ra­dioac­tiv­ity, op­er­at­ing on the as­sump­tion that pro­tect­ing against one will pro­tect against the other.

That as­sump­tion — which Cana­dian Nu­clear Safety Com­mis­sion of­fi­cials said is a com­mon, in­dus­try-wide as­sump­tion — proved false late last year when unan­tic­i­pated al­pha con­tam­i­na­tion was dis­cov­ered in the re­ac­tor vault where up to 563 peo­ple had been work­ing.

The com­pany even­tu­ally con­cluded that 195 work­ers had been suf­fi­ciently ex­posed to war­rant test­ing.

Pre­lim­i­nary re­sults on 14 of the work­ers deemed to have been among the most ex­posed have so far found al­pha ra­di­a­tion lev­els that are less than half the safe limit pre­scribed by the nu­clear safety watch­dog.

At Thurs­day’s CNSC hear­ing into the in­ci­dent, agency in­spec­tors said they’ve found no ev­i­dence that the ra­di­a­tion leaked be­yond the re­ac­tor vault or en­dan­gered the pub­lic.

Com­mis­sion mem­ber Ron­ald Bar­ri­ault sug­gested Bruce Power, the coun­try’s only pri­vate nu­clear sta­tion op­er­a­tor, was lucky the in­ci­dent wasn’t far more se­ri­ous.

“It’s more by good for­tune than by good in­dus­trial hy­giene man­age­ment that you don’t have a se­ri­ous prob­lem in the sense of ra­di­a­tion sickness,” he said.

Com­pany of­fi­cials ac­knowl­edged they could have done bet­ter but con­tended they took steps that min­i­mized the risk. Bar­ri­ault con­ceded the point and with­drew his com­ment.

The trou­ble started late last Novem­ber as work­ers, us­ing spe­cial tools de­signed to min­i­mize dust, were grind­ing the pipes that carry coolant to the Unit 1 re­ac­tor, which has been shut down for al­most 15 years. They’d done the same job on the Unit 2 re­ac­tor a month be­fore without in­ci­dent and as­sumed the same pro­ce­dures would be suf­fi­cient.

“With hind­sight, it would have been pru­dent to re­visit th­ese un­der­ly­ing as­sump­tions,” Nor­man Sawyer, ex­ec­u­tive vice-pres­i­dent and chief nu­clear of­fi­cer at the Bruce A plant, told the hear­ing.

Sawyer said beta ra­di­a­tion lev­els in nu­clear plants are typ­i­cally 10,000 times that of al­pha lev­els. Hence, they rou­tinely mon­i­tor for beta, even though ex­po­sure to al­pha par­ti­cles is ac­tu­ally more danger­ous.

How­ever, in this in­stance they even­tu­ally found the ra­tio of beta to al­pha was sig­nif­i­cantly re­duced — only seven to one — due to the fact that the re­ac­tor had been idle for years and beta de­cays faster.

“There is a bit of a mind­set is­sue here in that we’re looking for the beta and not di­rectly for the al­pha,” con­ceded Frank Saun­ders, vi­cepres­i­dent of over­sight and reg­u­la­tory af­fairs.

Com­pound­ing the prob­lem, the com­pany could not quickly as­sess how danger­ous the ex­po­sure to its work­ers had been be­cause there is only one ac­cred­ited fa­cil­ity in Canada — at Chalk River — that con­ducts the time-con­sum­ing tests. It in­tends to test all 195 work­ers deemed to have been at risk.

The Cana­dian Press

Bruce Power ra­di­a­tion pro­tec­tion pro­grams man­ager Mau­reen McQueen (left) and vice-pres­i­dent nu­clear over­sight and reg­u­la­tory af­fairs Frank Saun­ders ap­pear be­fore the Cana­dian Nu­clear Safety Com­mis­sion hear­ing into ra­dioac­tive con­tam­i­na­tion of work­ers in Ottawa, Thurs­day.

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