ALARA as a detriment

["Ted Rockwell" <tedrock@cpcug.org>]

Friends:



Some of you may be interested in a note I just received from a colleague who

was working as an outside contractor at Davis-Besse.  It illustrates one of

the major drawbacks in the Precautionary Principle--the idea that certain

outcomes are so intolerable that one must pay almost any price to avoid

them.  This was a guiding principle during the Cold War, when anyone who was

anti-communist was considered a friend of the U.S.  On this basis, we armed

Iraq as a bullwark against Iran, then armed Iran as an ally against Iraq.

meanwhile arming and training Ben Ladin and friends.  We have tended to

treat ALARA that way.  Art Upton and others tell me, "You may well be right,

that there is no harm at low levels.  But we just want to be conservative."

That type of "conservatism" does not always lead to lower risk.

________________________________



Hi Ted.  I know you consider that ALARA can add unnecessary costs to

operating nuclear power plants.  Here is another arrow for your quiver.



The industry is familiar with the Davis-Besse story.  Years ago, a small

leak developed in a reactor vessel head pipe penetration.   The leaking

reactor coolant, borated water, is highly corrosive to carbon steel

materials and was particularly corrosive at the interface between the

penetration weld material, Inconel 600, and carbon steel head material.

Over the years, the amount of leakage grew as evidenced by the amount of

boric acid crystals collected on the head of the Rector Vessel. This

amounted to hundreds of pounds of crystalline boric acid on the head,

and hundreds of pounds more which was released as vapor and  collected

throughout the containment vessel, particularly in the air handling

units.  The amount of head corrosion also was increasing, but the plant

operators were not aware of this. The head was finally inspected in the

spring of 2002.  The inspection revealed a hole which had penetrated

through all of the carbon steel head material down to the thin stainless

steel liner, which protects the reactor vessel from the reactor coolant.

The plant shut down, and is still not operating in the spring of 2003.

The details of this incident are available at the NRC's website,

www.nrc.gov, and the links to Davis Besse show the magnitude of the

issue.



This event could have been avoided if an inspection had been performed,

either preemptively based on French operating experience, or soon after

the plant operators were aware that a leak existed. An obvious question

is why such an inspection was not performed, particularly since the

requirements of ASME Section XI require an inspection if pressure

boundary leakage is suspected.



Two primary factors were involved.  One was the plant operators desire

to maintain a high rating from INPO (Institute for Nuclear Plant

Operations)  One of the major factors INPO uses in judging how well a

plant is being operated is low collective dose.

The collective dose for the entire nuclear industry, as well as for

individual plants, is published each year to show how well the industry

is doing.



The second, and related factor , was ALARA,  The concept of minimizing

all radiation dose was so firmly ingrained at the plant and enforced by

the Radiation Control department, that the ISI (In Service Inspection,

the program which executes the inspections for ASME Section XI)

engineers who could have performed a meaningful inspection were not

allowed near the reactor vessel head.  The personnel dose resulting from

such an inspection would have been well within the regulatory limits,

and within the even lower limits imposed by the plant operators.

However, the inspection was delayed for years in order to minimize

exposure.  Hundreds of millions ($350+)of dollars later, the plant

operators certainly regret their strong adherence to ALARA  and the INPO

low dose rating criteria in this case.

____________________________________________



Ted Rockwell