1、Lessons Learned Entry: 1391Lesson Info:a71 Lesson Number: 1391a71 Lesson Date: 2003-09-11a71 Submitting Organization: JSCa71 Submitted by: ave T. Loyd/Angela Luna/Ronald A. MontagueSubject: Detection of Steam Pipe Wall Thinning Due to Corrosion Abstract: Systemic management and technical failures le
2、d to the catastrophic rupture of a test system. 3 lessons are published regarding this specific incident; this lesson addresses problems with the detection of pipe wall thinning due to corrosion and the selection of inadequate test methods.Description of Driving Event: On September 11, 2003, at appr
3、oximately 2:16 PM, the steam line on the Large Altitude Simulation System (LASS) suffered a catastrophic failure of the 24-inch expansion loop located adjacent to the Test Stand 401 steam ejector exhaust duct. The LASS was being operated to verify its readiness to support an altitude firing of the 4
4、th stage of a Minuteman ICBM scheduled for September 25, 2003. The failure occurred approximately 16 seconds after the LASS was commanded to go to full steam, and resulted in a rupture of a portion of the line that dislocated several pieces of the 24-inch pipe in various directions away from the tes
5、t stand. The proximate cause of the event was pipe wall corrosion that led to selective thinning of the wall, which resulted in the pipe rupture under pressure. The following observations came from the investigation: 1. During the mishap investigation, evidence of rust scale deposits around steam li
6、ne drains (or “exhaust ducts”) was observed. This is an indicator that internal corrosion and erosion is taking place in the system.External corrosion products on the pipes were also observed, especially where external insulation trapped water from environmental sources. Provided by IHSNot for Resal
7、eNo reproduction or networking permitted without license from IHS-,-,-1. In piping subject to corrosion, it is difficult to determine the location of old pipe wall thinning in complex installations without 100% surveying.2. At the same time, Non-Destructive Evaluation techniques for determining stea
8、m pipe wall thickness were found to be inconclusive due to the detritus from internal corrosion remaining in place primarily on the inside of pipe walls.3. In this particular case, an alternative method to assess system integrity - hydrostatic pressure testing of old or modified fluid handling lines
9、 - was not an effective means of verification of long-term pressure integrity.Lesson(s) Learned: Methods of evaluating critical system parameters must be verified as sufficiently reliable to support risk assessmentRecommendation(s): 1. Contingent on system design life requirements, develop and imple
10、ment a corrosion survey plan for all of the steam lines and ejector duct that includes documenting the results and location of pipe inspections, comparing results from year to year, documenting any trends that may develop, and stating clearly the minimum passing criteria for each inspection.2. 3. As
11、sure thoroughness and follow-through in the Systems Requirements Review process for affected facilities.4. Assure rigor exists in the Pressure Systems inspection program, including a process for tracking and follow-up on corrections for non-compliances.Evidence of Recurrence Control Effectiveness: N
12、/ADocuments Related to Lesson: NPD 8710.5A NASA Safety Policy for Pressure Vessels and Pressurized Systems; JHB 1710.13B Design, Inspection, and Certification of Pressure VesselsMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchProvided by IHSNot f
13、or ResaleNo reproduction or networking permitted without license from IHS-,-,-Additional Key Phrase(s): a71 Configuration Managementa71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Energya71 Facilitiesa71 Ground Equipmenta71 Ground Operationsa71 Hardwarea71 Industrial Operationsa71 Part
14、s Materials & Processesa71 Policy & Planninga71 Pressure Vesselsa71 Program and Project Managementa71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test & Verificationa71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 2004-04-26a71 Approval Name: Ronald A. Montaguea71 Approval Organization: JSCa71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
