This　paper　reports　a　fundamental　experimental　investigation　of　the　start-up　characteristics　of　heat　pipes　using　a　dedicated　molten-salt　mixture　as　the　working　fluid.　Based　on　four　single　salt,　i.e.　NaNO3(AR),　KNO3(AR),　LiNO3(AR)　and　Ca(NO3)(2)(AR),　a　quaternary　molten-salt　working　fluid　was　developed　and　charged　at　different　masses　into　four　heat　pipes　with　the　same　dimensions　of　980　mm　in　length　and　22　mm　in　diameter.　A　parallel　comparison　on　the　start-up　performance　of　these　heat　pipes　was　then　conducted　to　observe　the　influence　of　the　charging　mass　and　the　inclination　angle　under　the　consistent　lab　controlled　conditions.　The　experimental　results　showed　the　heat　pipe　with　molten-salt　charge　of　40　g　responded　much　quicker　than　those　with　molten　salt　charge　of　60　g,　70　g　and　80　g　respectively;　meanwhile,　the　molten-salt　heat　pipe　achieved　the　maximum　condensation　temperature　at　inclination　angle　of　50　degrees.　Comparing　to　the　conventional　naphthalene　heat　pipe,　the　dedicated　molten-salt　heat　pipe　had　a　much　shorter　start-up　time　when　they　were　charged　with　the　same　amount　of　40　g.　The　overall　research　result　is　expected　to　provide　certain　guidance　for　further　design　and　operation　of　molten-salt　heat　pipe　in　high-and-medium-temperature　heat　transfer　and　storage　scenarios.　(C)　2016　Elsevier　Inc.　All　rights　reserved.