The light-independent reactions of photosynthesis are chemical reactions collectively called the Calvin cycle occurs only when light is available. Plants do not carry out the Calvin cycle during nighttime. They instead release sucrose into the phloem from their starch reserves.
Carbon fixation or сarbon assimilation The most prominent example is photosynthesis, although chemosynthesis is another form of carbon fixation that can take place in the absence of sunlight.
Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Benison Cycle, and it occurs in the stroma.
we find that light-independent reactions, carbon dioxide fixation - takes place in sunlight n ofcourse is a long process but not dark reaction. Please ref images