K. Makela et P. Aaltonen, ONLINE MONITORING FOR FURTHER CORROSION REDUCTION AND BETTER UNDERSTANDING OF THE ACTIVITY BUILDUP IN LWR PRIMARY COOLANT SYSTEMS, International journal of pressure vessels and piping, 55(1), 1993, pp. 163-177
Uniform corrosion rates of materials in contact with the coolant in bo
iling water reactors (BWRs) and pressurized water reactors (PWRs) are
low and this kind of material degradation is very unlikely to compromi
se the integrity of the primary pressure boundary. In a properly contr
olled environment the initial corrosion rates decrease reaching the lo
w corrosion rate, typical for the steady state between the outer oxide
surface and the environment. The water chemistry practice modificatio
ns can be used to decrease fuel corrosion, improve material integrity
and slow down activity build-up in the primary circuit. Therefore, on-
line water chemistry monitoring at high temperatures should be conduct
ed to obtain local, reliable and thus useful information over long mea
surement periods at a specific loop site. In this paper, the effect of
water chemistry on the corrosion product formation, activation, trans
port and redeposition on out-of-core surfaces is discussed.