REG NASA-LLIS-0299-1993 Lessons Learned - Dry Well Transducer Installations are Susceptial to Inadvertent Removal.pdf

1、Lessons Learned Entry: 0299Lesson Info:a71 Lesson Number: 0299a71 Lesson Date: 1993-08-18a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: Dry Well Transducer Installations are Susceptial to Inadvertent Removal Description of Driving Event: A Hypergol technician erred in the

2、 removal of a temperature transducer from a 3-inch Hypergol line at the pad “A“ fuel farm, resulting in a major fuel spill. The installation design of the dry well and temperature transducer provide a means to remove the transducer from the system for replacement or calibration without having to ope

3、n the fluid volume. The dry well installation design is inadequate to preclude an untrained or careless technician from inadvertently removing the dry well from the Hypergol propellant line by mistake.Additional Comments:OMI V2196 Titled: “Hyper Fuel System Validation Storage Area-Local Control/LPS“

4、 has been updated to include the following warning: “Removing transducers from dry wells may be hazardous. A restaining retainer is designed to prevent removal of dry well while secured in place by set screws. As transducers are being removed from dry wells, PMTG shall visually verify that dry wells

5、 are not turning. Wear face shield, apron and rubber gloves and use extreme care to avoid inadvertent loosening of any temperature XDCR dry well, which could release MMH liquid. If A78633 TEMP XDCR dry well is loosened the entire storage tank contents could be released.“Lesson(s) Learned: Adequate p

6、hysical safeguards do not exist to prevent the inadvertent removal of dry well transducer installations from hazardous systems. See DWG 79K16420 Dry Well Assembly.Recommendation(s): To prevent the inadvertent removal of dry wells from hazardous systems, dry wells should be Provided by IHSNot for Res

7、aleNo reproduction or networking permitted without license from IHS-,-,-secured using an appropriate restraining device, capable of holding the dry well in place while transducers are removed and replaced.Evidence of Recurrence Control Effectiveness: The supervisor was contracted to verify the insta

8、llation of dry well restraining retainers. In addition, the supervisor said the dry well restraining retainers have been very effective in preventing dry well backouts. There have been no recorded instances of backouts by dry wells with the restraining device installed. Installation and effectivenes

9、s of the dry well restaining retainers was also verified at PAD B.Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Facilitiesa71 Hazardous/Toxic Waste/MaterialsAdditional Info: Approval Info: a71 Approval Date: 1994-06-15a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-