What is the primary purpose of Steam Generator Blowdown in a nuclear plant?

• A. Fresh feedwater impurities only
• B. Steam Generator Blowdown removes deposits and dissolved solids
• C. Vent excess steam
• D. Reduce radiation by shielding

Answer: (B)

The main idea is impurity control in the steam generator’s secondary side. As feedwater is boiled and turned into steam, minerals and corrosion products can become concentrated in the water circulating in the steam generator. If these dissolved solids and deposits build up, they form scale on heat-transfer surfaces, reduce heat transfer efficiency, and can accelerate corrosion of the tubes. Steam Generator Blowdown periodically dumps a portion of that water and replaces it with fresh makeup water, thereby removing the concentrated impurities and any deposits. This keeps the chemistry and concentration within design limits, preserving heat transfer performance and tube integrity.

That’s why removing deposits and dissolved solids is the best description of its primary purpose. The other options don’t capture the main function: it’s not about venting excess steam, shielding radiation as the primary goal, or focusing solely on impurities in fresh feedwater.