Steam generator blowdown processing system

The radiation monitors associated witii the steam generator blowdown system provide a means of recognising when the secondary side becomes radioactively contaminated, an indication of a steam generator tube mpture. The blowdown flow and the ion exchange waste stream (brine) flow are both continuously monitored for radioactivity. If such radioactivity is detected, the liquid radwaste system is aligned to process the blowdown and ion-exchange waste effluent. If radioactivity should exceed a preset level, the blowdown flow control valves and the isolation valves would automatically close. 

An alarm sounds in the main control room on detection of a high radiation level within the blowdown system, to alert the operators of the need to take the appropriate remedial action, such as aligning the liquid radwaste system to process the blowdown and ion-exchange waste effluent, and isolating the affected steam generator (Section 10.4.8.2.2 of Reference 6.1). 

The wastewater from a hydrogen plant typically consists of only the blowdovm from the boiler system. The boiler feedwater that feeds the steam generation system has small amounts of impurities such as sodium, chlorides, silica, and organic carbons. These impurities will accumulate within the boiler system and create sludge, scaling of the boiler tubes, and possible carryover of solids into the process steam. Blowdown of the boiler water is performed to prevent these issues from affecting the operation of the steam system. The blowdown is typically sent to the sewer or the on-site waste treatment plant for treatment and disposal. 

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