Stellite Reduction

[Roll Tide]

I recently was briefed on a new program that sounds like an odd cross between FME, RADCON, and Chemistry. We are going to try to reduce loose stellite in new components in order to reduce the amount of Co-60 after activation.

I would love to have some anecdotal evidence for successes in this area. I haven't been able to pin anyone down to specifics, but "some other plants" have significantly reduced shutdown doserates.

Thanks!

[Roll Tide]

Let me clarify: I would like to hear the experiences of my fellow techs that have been involved with this, regardless of success or failure.

[Roll Tide]

Is this thing on??

[MrHazmat]

BREAKER BREAKER RT................You coming in loud and clear 

[garcma]

I have to ask the obvious....what is stellite?

[Nuclear NASCAR]

[n]  (trademark) a cobalt-base alloy with chromium and other metals; very hard; used to make cutting tools and for surfaces subject to heavy wear 

Chronic health effects specific to an element may be difficult to detect due to the numerous elements in this alloy. Chronic inhalation effects may include chronic obstructive lung disease, pulmonary fibrosis, rhinitis and/or bronchitis. Chronic occupational exposure to cobalt has been associated with polycythemia (an increase in the total cell mass of the blood), bloody urine, and goitre (enlargement of the thyroid gland).

[grantime]

My plant is starting to look at this.  If we can reduce the amount of stellite in system we will reduce the amount of Co-60 formed.  We have already done the common things of trying to reduce the amount of stellite valve seats in the system.  The focus now will be on reducing the amount of Co that is loose on outside of new components as well as reducing any added to system from valve work.

What levels are you trying to get to?  Is it a ppm level or by weight?

We are currently looking at instrumentation.  Do you have any suggestions?  Some of what we are looking at is lab grade stuff.  Awfully expensive and not portable.  There are some portable allow type testers that may work. 

We are just starting to look at it here and I have more questions than answers. 

[bjb]

I think it is:
Stellite:
The build-up of crud and crap in the piping, valves and any other area of the reactor. Causes corrision and high activity rates.

[RDTroja]

I think it is:
Stellite:
The build-up of crud and crap in the piping, valves and any other area of the reactor. Causes corrision and high activity rates.

Ummm... that is not a definition of stellite. See Nuclear Nascar's post above. Stelleite is a specific very hard cobalt alloy used in valve seats that gets loose in the RCS through corrosion and wear and then becomes activated. It is the major source of Cobalt-60 in the waste stream of a nuclear plant. Thus the high dose rates (two reasonably hard gammas per decay.)