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Sent by: STRUCTURES LAB,CSULB 562 965 4406 r • 06/09/99 12:13 Job 177 Page 3/3 cif about i ,psi (about 8 hour period) on the annular space water is still evident at the lowest point or at the location of ehe elect P on13-. Determine «-hether ��r not water is present at the location of the electronic sensor, a s • runic sensor. it' no conducted per recommendations of -CS to certify the tank. If standard the Pressure test pass, then I believe the tank should be tI f Nord vacuum test shalt e vacuum and the considered acceptable and certifiable. If either the vacuum or pressure test fail in the last part of St 2, the ' the secondary wall is leaking Step n it is evident that my opinion that the locationf this cracked secondarthe annular y walla io on Pa experience, it is determine, even with the use of helium or other t n is difficult to the concrete slab has been S pes of tracing gases, especially when Poured over the tank_ If no other procedure is feasible in determining Whether or not the Seco the tank be removed from the o ndary shelf is leaking, I would then recommend that be employed to determine the location atti n of the leakage nd and the aolloiwe ores recommended by ('S Procedures outlined by CS. b3' repair, utilizing the 4- To pressurize the annular region alone requires considerable care, to avoid damage to the tanks. It is, therefore. recommended to pressurize therim ri p �]' tank, bleed into the annular region, then remove the pressure from the P maty mak• While removing the pressure from the Primary tank, the valve to the annular space should be closed. It is possible that the pressure in the annular space will drop significantly after the primary tank has been depressurized, due to the elastic deformations of the primary shell. Therefore, this process may have to be repeated several times, to attain a reasonable pressure of about 3 psi in tie annular region only. The pressure in the primary tank should be the maximum prcb'bed by CS for such a testing procedure. If you have any questions, please call me at (562) 985-4406.