A. Alsammarae et al., REEVALUATION OF SUPERHEAT CONDITIONS POSTULATED IN NRC INFORMATION NOTICE 84-90, IEEE transactions on nuclear science, 41(4), 1994, pp. 1389-1393
Information Notice 84-90, ''Main Steam Line Break Effect on Environmen
tal Qualification of Equipment'' [1], describes a potential problem re
garding existing plant analyses and Equipment Qualification (EQ) relat
ed to a postulated Main Steam Line Break (MSLB) with releases of super
heated steam. This notice states that certain methodologies for comput
ing mass and energy releases for a postulated MSLB did not account for
heat transfer from the steam generator tube bundles if they were unco
vered. Due to this potential change in the original environmental anal
ysis, the EQ of various components may not consider the thermal enviro
nment which could result from superheated steam. Subsequent technical
assessments may determine that the existing qualification basis for eq
uipment/components does not envelop the postulated superheat condition
. Corrective actions need to be taken to demonstrate that the affected
equipment is qualified.