REG NASA-LLIS-0406-1996 Lessons Learned - B-1 Test Stand Vent Line Overpressurization.pdf

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1、Lessons Learned Entry: 0406Lesson Info:a71 Lesson Number: 0406a71 Lesson Date: 1996-06-18a71 Submitting Organization: SSCa71 Submitted by: Mike RewisDescription of Driving Event: On Feb. 8, 1996 at 10:04 AM on the B-1 Test Stand, a vent line overpressurization and subsequent rupture occurred. No per

2、sonnel injuries resulted. Failure damage included the ruptured piping and deformed pipe supports.Lesson(s) Learned: It is essential for unspent fuel being exhausted through vent lines to be kept as free of oxygen as possible. In the case of this mishap, it was found that air was being intrained in t

3、he vent system via an undetected rupture disc vaccuum break. This air, which liquified after “puddling“ in vent line low points, in combination with the routinely vented gaseous hydrogen, and a flame front emanating from a downline flare stack created an overpressurization event which thereby compro

4、mised the piping.Recommendation(s): Several corrective actions were taken:1. Suspect rupture disk removed from system with no safety impact2. O2 meter installed in vent line piping3. New vent line per SSC/NASA standards4. Enhancement of SSME drying operations to allow for blanket fuel system purge5.

5、 Inspection of all rupture disks in use on the B-1 Test StandEvidence of Recurrence Control Effectiveness: The O2 sensor, located optimally for detecting either diffused or stratified oxygen, has experienced no indication of oxygen concentration spikes the in the system. At the trigger point, equal

6、oxygen to Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0.5% oxygen concentration, the meter both produces an audible alarm and an automatic gasseous nitrogen purge is initiated.Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional

7、Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Hazardous/Toxic Waste/Materialsa71 Pressure VesselsAdditional Info: Approval Info: a71 Approval Date: 1996-06-18a71 Approval Name: Mike Rewisa71 Approval Organization: SSCa71 Approval Phone Number: 601-896-4723Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-