Method for forming and maintaining a fundamentally impervious boundary to very high purity hydrogen in a salt cavern

A method for forming and maintaining a fundamentally impervious boundary to very high purity hydrogen stored in a salt cavern, comprising a salt cavern wall, the salt cavern comprising one or more of the following attributes:

• salt having a mean creep constant along substantially the entire cavern wall of less than 1.5×10-301/(psfn*sec),
• salt having a mean tensile strength along substantially the entire cavern wall of less than 200 psi,
• salt having a mean compressive strength along substantially the entire cavern wall of less than 2700 psi,
• salt with a mean Young's Modulus along substantially the entire cavern wall of more than 4,000,000 psi,
• the method comprising:
• introducing a compressed very high purity hydrogen gas into a salt cavern, thereby producing a stored very high purity hydrogen gas;
• forming a fundamentally impervious boundary to the very high purity hydrogen along at least a part of the perimeter of the salt cavern, and
• maintaining the fundamentally impervious boundary to the stored very high purity hydrogen gas at a pressure greater than 1.1 psi per linear foot of height within the cavern, and less than 4.0 psi per linear foot of height within the cavern and thereby retaining within the salt cavern over 95% of the stored very high purity hydrogen over a period of time of at least 72 hours.