"Slow going on MAPLE"

["Jaro" <jaro-10kbq@sympatico.ca>]

A while back someone asked about progress at the MAPLE project at Chalk

River Laboratories.

Here's the latest public info on that.



Jaro

http://www.cns-snc.ca/branches/quebec/quebec_main.html

^^^^^^^^^^^^^^^^^^^^^





http://www.magma.ca/~drcanrt/mapleslow.htm

Slow going on MAPLE

by Terry Myers

The North Renfrew Times, October 8, 2003



Atomic Energy of Canada Ltd. is still trying to figure out what went wrong

in tests of the new MAPLE 1 reactor at the Chalk River Laboratories.



Company officials told the Canadian Nuclear Safety Commission (CNSC)

recently that they are still trying to find out why the reactor did not

operate the way it was designed to.



Jean-Pierre Labrie, general manager of the MAPLE reactor project, said AECL

is still working on its computer simulations.



"We have had to go to more sophisticated computer codes to analyze the

behaviour we have seen from our commissioning results and we are still in

the middle of these calculations," he said.



"These are very complex and time consuming in terms of computer time

calculations.



"They are multi-calculations with particle simulations, so they take a long

time to run."



The MAPLE 1 reactor at Chalk River was placed in a "secure shutdown state"

in June after tests showed the reactor operating with a "positive power

coefficient."



The MAPLE reactor is designed to operate with a negative coefficient.



In rough terms, a reactor with a negative coefficient will gradually slow to

a stop if safety systems fail and there is no one at the controls.



A reactor with a positive coefficient would instead run faster and hotter

until it reaches the point of a meltdown.



In a report to members of the safety commission, Barclay Howden, the acting

director general of nuclear facilities regulation for the CNSC, said the

positive reading for MAPLE 1 was "contrary to the (reactor's) core design

characteristic" and "could have a negative impact on safety."



However, officials from AECL told the CNSC in July that they expect the

finding to have no effect on the reactor's "safety case."



In fact, they said the power coefficient - a combination of several

competing factors - may even fall to zero or become negative when the

reactor reaches full power.



Gary Kugler, vice-president of nuclear products and services for AECL, said

the company had expected to find a small negative result, but instead came

up with a small positive finding.



"Had we predicted a larger and negative coefficient and found in the

experiment a smaller negative coefficient, it probably would not have become

an issue at all," he said.



"But the fact that it went from slightly negative to slightly positive

certainly does require an explanation...



"So we are certainly looking into this very carefully. We need to understand

it."



Howden told the commission members he expects to receive AECL's final

reports on the issue by the end of October.



Low power



While AECL is still analyzing the commissioning results, work on the two

MAPLE reactors being built at Chalk River is moving forward slowly.



The CNSC has given AECL permission to start up the MAPLE 1 again and run it

at low power so the company can continue to test the reactor's shut-off

systems.



AECL has also begun commissioning the MAPLE 2 reactor.



The reactor was loaded with fuel and was expected to begin "the final

approach to critical" last week.



AECL is building the two 10-megawatt MAPLE reactors and a new isotope

processing facility (NPF) at Chalk River under contract with MDS Nordion.



Once complete, the MAPLE facilities will produce medical isotopes like

Molybdenum-99 that Nordion markets around the world, a job now done at the

NRU reactor.



The MAPLE project fell about two years behind after problems with the

shut-off rods, one of the reactor's emergency safety systems, were

discovered in July 2000.



Earlier this year, AECL announced new target dates for the completion of the

project.



AECL said it hoped to have MAPLE 1 declared "in service" as of September 19,

while the target for MAPLE 2 was December 19.



-------------------------------





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