Patent Number: 
Section: claims

1. A construction layout for caverns of an underground nuclear power plant, the construction layout comprising:a) two nuclear island powerhouse cavern groups, each nuclear island powerhouse cavern group comprising:a1) a primary cavern accommodating nuclear reactor powerhouse;a2) an electric powerhouse cavern;a3) a safe powerhouse cavern;a4) an auxiliary powerhouse cavern;a5) a nuclear fuel powerhouse cavern; anda6) a connecting powerhouse cavern;b) a first primary traffic tunnel;c) a second primary traffic tunnel;d) a third primary traffic tunnel;e) a fourth primary traffic tunnel;f) two primary steam channels;g) a bottom adit system; andh) a top adit system comprising:h1) a first primary adit;h2) a second primary adit;h3) a third primary adit; andh4) a fourth primary adit;wherein:the electric powerhouse cavern, the safe powerhouse cavern, the nuclear auxiliary powerhouse cavern, the nuclear fuel powerhouse cavern, and the connecting powerhouse cavern are disposed around the corresponding primary cavern;a connecting line of centers of cross-sections of the two primary caverns at a horizontal plane is perpendicular to a longitudinal direction of a mountain in which the underground nuclear power plant is constructed, wherein the horizontal plane is parallel to a ground surface and the longitudinal direction of the mountain;each of the electric powerhouse cavern, the safe powerhouse cavern, the nuclear auxiliary powerhouse cavern, the nuclear fuel powerhouse cavern, and the connecting powerhouse cavern comprises a rectangular cross-section having a longitudinal axis at the horizontal plane;the longitudinal axes of the electric powerhouse cavern, the safe powerhouse cavern, and the nuclear fuel powerhouse cavern are arranged along the longitudinal direction of the mountain; the longitudinal axes of the auxiliary powerhouse cavern and the connecting powerhouse cavern are arranged perpendicular to the longitudinal direction of the mountain and parallel to the ground surface;the safe powerhouse cavern and the nuclear fuel powerhouse cavern are disposed on two sides of the primary cavern, respectively; the electric powerhouse cavern and the safe powerhouse cavern are located on a same side of the primary cavern; the auxiliary powerhouse cavern and the connecting powerhouse cavern are disposed on two sides of the primary cavern, respectively;two primary caverns are disposed between the first primary traffic tunnel and the third primary traffic tunnel; the second primary traffic tunnel is disposed between the two primary caverns;the fourth primary traffic tunnel is disposed perpendicular to the longitudinal direction of the mountain and parallel to the ground surface;the fourth primary traffic tunnel is connected to the first primary traffic tunnel, the second primary traffic tunnel, and the third primary traffic tunnel;one of the two nuclear island powerhouse cavern groups is surrounded by the fourth primary traffic tunnel together with the first primary traffic tunnel and the second primary traffic tunnel, and the other of the two nuclear island powerhouse cavern groups is surrounded by the fourth primary traffic tunnel together with the second primary traffic tunnel and the third primary traffic tunnel;the primary cavern communicates with the corresponding connecting powerhouse cavern via one of the two primary steam channels;the first primary adit, the second primary adit, the third primary adit, and the fourth primary adit of the top adit system are disposed along the longitudinal direction of the mountain, and are connected to the ground surface;skewbacks or endwalls of top arches of the caverns of each nuclear island powerhouse cavern group communicate with the ground surface via the first primary adit, the second primary adit, the third primary adit, and the fourth primary adit of the top adit system;the first primary traffic tunnel, the second primary traffic tunnel, the third primary traffic tunnel, and the two primary steam channels are disposed along the longitudinal direction of the mountain, and are connected to the ground surface;bottoms of sidewalls of the caverns of each nuclear island powerhouse cavern group communicate with the first primary traffic tunnel, the second primary traffic tunnel, the third primary traffic tunnel, the fourth primary traffic tunnel, and the primary steam channel via the bottom adit system, and the bottoms of sidewalls of the caverns of each nuclear island powerhouse cavern group communicate with the ground surface via the first primary traffic tunnel, the second primary traffic tunnel, the third primary traffic tunnel, and the primary steam channel;the first primary adit, the second primary adit, the third primary adit, and the fourth primary adit are disposed at a higher elevation with respect to the first primary traffic tunnel, the second primary traffic tunnel, the third primary traffic tunnel, and the two primary steam channels;the first primary adit, the second primary adit, the third primary adit, and the fourth primary adit are adapted for construction; andthe first primary traffic tunnel, the second primary traffic tunnel, the third primary traffic tunnel, and the two primary steam channels are adapted for slag discharge. 2. The construction layout of claim 1, wherein the top adit system further comprises: a first top adit of a first primary cavern, a second top adit of a second primary cavern, third top adits of the nuclear fuel powerhouse caverns, fourth top adits of the connecting powerhouse caverns, fifth top adits of the electric powerhouse caverns, seventh top adits of the safe powerhouse caverns, an eighth top adit of the auxiliary powerhouse caverns, and ninth top adits of the safe powerhouse caverns;an elevation of the first primary adit is higher than an elevation of the second primary adit, an elevation of the third primary adit, and an elevation of the fourth primary adit; the first primary adit is connected to skewbacks of top arches of the two primary caverns;the second primary adit and the fourth primary adit are respectively connected to endwalls of top arches of outer end faces of the auxiliary powerhouse caverns; two ends of the eighth top adit are respectively connected to endwalls of top arches of inner end faces of the two nuclear auxiliary powerhouse cavern; one end of the third primary adit is connected to a middle section of the eighth top adit;the second primary adit is connected to an endwall of a top arch of a first nuclear fuel powerhouse cavern via one of the third top adits; the third primary adit is connected to an endwall of a top arch of a second nuclear fuel powerhouse cavern via the other of the third top adits;the third primary adit is connected to an endwall of a top arch of a first connecting powerhouse cavern via one of the fourth top adits; the fourth primary adit is connected to an endwall of a top arch of a second connecting powerhouse cavern via the other of the fourth top adits; the fourth top adits are connected to endwalls of top arches of the electric powerhouse caverns via the fifth top adits, respectively; andthe third primary adit is connected to an endwall of a top arch of one end of a first safe powerhouse cavern via one of the seventh top adits; the eighth top adit is branched to form one of the ninth top adits connected to an endwall of a top arch of the other end of the first safe powerhouse cavern; one of the ninth top adits is disposed between an inner end face of a first nuclear auxiliary powerhouse cavern and the third primary adit; the fourth primary adit is branched to form the other of the seventh top adits; and the other of the seventh top adits and the other of the ninth top adits are connected to endwalls of top arches of two ends of a second safe powerhouse cavern. 3. The construction layout of claim 1, wherein the two primary caverns are provided with first apparatus conveying channels for communicating with corresponding connecting powerhouse caverns; and a bottom of a sidewall of each of the connecting powerhouse caverns communicates with the ground surface via a second apparatus conveying channel. 4. The construction layout of claim 2, wherein, each top adit of the top adit system has a longitudinal slope smaller than 12%. 5. The construction layout of claim 2, whereinthe bottom adit system comprises: first bottom adits of the two primary caverns, second bottom adits of the electric powerhouse caverns, third bottom adits of the safe powerhouse caverns, fourth bottom adits of the auxiliary powerhouse caverns, fifth bottom adits of the nuclear fuel powerhouse caverns, and sixth bottom adits of the auxiliary powerhouse caverns;the first primary traffic tunnel is connected to a bottom of a sidewall of a first primary cavern via one of the first bottom adits; the second primary traffic tunnel is connected to a bottom of a sidewall of a second primary cavern via the other of the first bottom adits;each primary steam channel is connected to a bottom of a sidewall of corresponding electric powerhouse cavern via each second bottom adit;the two third bottom adits are disposed on the fourth primary traffic tunnel and are connected to bottoms of endwalls of corresponding safe powerhouse caverns; the two fifth bottom adit are disposed on the fourth primary traffic tunnel and are connected to bottoms of endwalls of corresponding nuclear fuel powerhouse caverns;the two fifth bottom adit are connected to bottoms of endwalls of one ends of corresponding auxiliary powerhouse caverns via sixth bottom adits of the auxiliary powerhouse caverns; andthe two third bottom adit are connected to bottoms of endwalls of the other ends of corresponding auxiliary powerhouse caverns via fourth bottom adits of the auxiliary powerhouse caverns. 6. The construction layout of claim 2, wherein the two primary caverns are provided with first apparatus conveying channels for communicating with corresponding connecting powerhouse caverns; and a bottom of a sidewall of each of the connecting powerhouse caverns communicates with the ground surface via a second apparatus conveying channel. 7. The construction layout of claim 4, wherein the two primary caverns are provided with first apparatus conveying channels for communicating with corresponding connecting powerhouse caverns; and a bottom of a sidewall of each of the connecting powerhouse caverns communicates with the ground surface via a second apparatus conveying channel. 8. The construction layout of claim 5, wherein each bottom adit of the bottom adit system has a longitudinal slope smaller than 15%. 9. The construction layout of claim 5, wherein the two primary caverns are provided with first apparatus conveying channels for communicating with corresponding connecting powerhouse caverns; and a bottom of a sidewall of each of the connecting powerhouse caverns communicates with the ground surface via a second apparatus conveying channel. 10. The construction layout of claim 8, wherein the two primary caverns are provided with first apparatus conveying channels for communicating with corresponding connecting powerhouse caverns; and a bottom of a sidewall of each of the connecting powerhouse caverns communicates with the ground surface via a second apparatus conveying channel.