The decryption of the lvm partition under the full disk encrypted disk which is encrypted by YaST

Full Disk Encrypted hdd is absent in the file system. Password is in my mind. A way to mount or decrypt the disk is all I ask. dm-crypt, cryptsetup, truecrypt; anything.

The installer did not let me decrypt during reinstalling thus aborted. esp /boot on it was erased hence the inability of the yast to decrypt in order to install.

cryptsetup luksOpen /dev/sda2 root
Device /dev/sda2 is not a valid LUKS device.
kts@linux-fkp2:~> sudo blkid
/dev/sda1: SEC_TYPE="msdos" UUID="CA8D-AC5C" TYPE="vfat" PARTUUID="1401b8e2-3bb9-4735-954c-0ec76e3a6faa"
/dev/sda2: UUID="cfe4d9ba-a20c-4122-8b08-19b7bbb1ab3d" TYPE="crypto_LUKS" PARTUUID="7f53bafb-92a6-4fe7-bd51-707f399f8456"
/dev/mapper/cr_ata-ST2000DM001-1CH164_W340DMWT-part2: UUID="siwRSg-8pxp-hTHc-70WP-BVx9-UCKQ-0HDtBq" TYPE="LVM2_member"
/dev/mapper/system-root: UUID="46646f65-0299-41e4-9fc2-19f861eafa52" UUID_SUB="8d386cb9-41a8-4702-b991-d762c61d561d" TYPE="btrfs"
/dev/mapper/system-swap: UUID="64e37461-5405-41b2-af09-0d763aa6b24d" TYPE="swap"
/dev/mapper/system-home: UUID="e73e3773-d4d1-42b4-b97f-27c074f5226a" TYPE="xfs"
/dev/sdg1: PARTUUID="16aaadd1-cc2d-4803-8eff-d5f187affdf3"
/dev/sdg2: UUID="tY8dmC-sg9W-ENuS-yK30-nlY0-9BCT-KEPmoH" TYPE="LVM2_member" PARTUUID="780434d8-cb13-4107-aee8-14dfc737a250"

/dev/sdg2 is the one that I intend to decrypt.

kts@linux-fkp2:~> sudo pvscan
  PV /dev/mapper/cr_ata-ST2000DM001-1CH164_W340DMWT-part2   VG system          lvm2 [1.82 TiB / 0    free]
  PV /dev/sdg2                                                                 lvm2 [1.82 TiB]
  Total: 2 [3.64 TiB] / in use: 1 [1.82 TiB] / in no VG: 1 [1.82 TiB]

This device is not encrypted.

kts@linux-fkp2:~> sudo blkid
/dev/sdg2: UUID="tY8dmC-sg9W-ENuS-yK30-nlY0-9BCT-KEPmoH" TYPE="LVM2_member" PARTUUID="780434d8-cb13-4107-aee8-14dfc737a250"