Regulatory Guide 1.80

Preoperational Testing of Instrument Air Systems

ML13064A110
Person / Time
Issue date:	06/30/1974
From:	US Atomic Energy Commission (AEC)
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References
RG-1.080
Download: ML13064A110 (2)

June 1974U.S. ATOMIC ENERGY COMMISSIONR E G U LAT. 0 YDIRECTORATE OF REGULATORY STANDARDSGUI DEREGULATORY GUIDE 1.80PREOPERATIONAL TESTING OF INSTRUMENT AIR SYSTEMSA. INTRODUCTIONGeneral Design Criterion -1, "Quality Standards andRecords," of Appendix A, "General Design Criteria forNuclear Power Plants," to 10 CFR Part 50, "Licensingof Production and Utilization Facilities," requires thatstructures, systems, and components important to safetybe tested to quality standards commensurate with theimportance of the safety functions to be performed.Criterion XI, "Test Control," of Appendix B, "QualityAssurance Criteria for Nuclear Power Plants and FuelReprocessing Plants," to 10 CFR Part 50 requires that atest program be established to assure that all testing,including preoperational testing required to demonstratethat structures, systems, and components will performsatisfactorily in service is identified and performed. Thisguide describes a method acceptable to the Regulatorystaff for complying with the Commission's regulationswith respect to verifying the operability of safety-relatedinstrument air systems 1 before placing these systemsinto service.B. DISCUSSIONOperation experience has shown that there is a needfor guidance in conducting an adequate preoperationaltest on the instrument air systems. There have been valveoperator failures due to foreign matter in the instrumentair, which would indicate .either inadequate cleaning ofthe system after installation or inadequate filtering ofthe supply air taken into the system during operation.There have been several incidents in which the air supplyto vital instruments was cut off due to the freezing ofexcessive moisture in the instrument air line. In one case,the freezing was the result of an improperly set dryerrefrigerant expansion valve. In other cases, the freezingwas caused by unusually cold weather.This guide should also be considered applicable toinstrument systems utilizing other gases such as nitrogen.The applicant is responsible for the development ofa suitable preoperational test program for the instrumentair system, the preparation of adequate procedures forcarrying out the program, the proper conduct of thepreoperational tests, and the validity of the test results.A significant consideration related to theperformance of the instrument air system is how thevalves controlled by the system will respond to the lossof instrument air supply. Valves are designed to respondin a given manner, i.e., fail open, fail closed, or fail as is,if the instrument air supply is lost. Verification of designresponse to a loss-of-instrument-air accident is anessential part of testing at the preoperational stage, atwhich time it can be accomplished with a minimum riskto power plant equipment and personnel. The test willalso provide a means for determining the adequacy ofoperating and emergency procedures for coping with aloss of instrument air supply.C. REGULATORY POSITIONAs part of the initial preoperational testing program,and also after major modifications or repairs to afacility, the instrument air system should be tested as.described below to verify that all components functionproperly and that the systems respond as designed to aloss-of-instrument-air-supply accident.1. The test program for the instrument air system andits associated equipment should include applicablechecks, verifications, tests, and reports outlined inRegulatory Guide 1.68, "Preoperational and InitialStartup Test Programs for Water-Cooled PowerReactors" as a prerequisite to or in conjunction with thetests of this regulatory guide.2. Compressors, aftercoolers, oil separator units, andair receivers should be tested to verify proper operationaccording to system design. Check operation ofcompressor unloaders, automatic and manual start andUSAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the divisionsdesired to the US. Atomic Energy Commission, Washington, D.C. 20545,Regulatory Guides are issued to describe and make available to the public Attention: Director of Regulatory Standards. Comments and suggestions formethods acceptable to the AEC Regulatory staff of implementing specific parts of improvements in these guides are encouraged and should be sent to the Secretarythe Commission's regulations, to delineate techniques used by the staff in of the Commission, U.S. Atomic Energy Commission, Washington. D.C. 20545,evaluating specific problems or postulated accidents, or to provide guidance to Attention: Chief, Public Proceedings Staff.applicants. Regulatory Guides are not substitutes for regulations and compliancewith them is not required. Methods and solutions different from those set out in The guides are issued in the following ten broad divisions:the guides will be acceptable if they provide a basis for the findings requisite tothe issuance or continuance of a permit or license by the Commission. 1. Power Reactors 6. Products2. Research and Test Reactors 7. Transportation3. Fuels and Materials Facilities 8. Occupational HealthPublished guides will be revised periodically, as appropriate, to accommodate 4. Environmentalland Siting 9. Antitrust Reviewcomments and to reflect new information or experience. 5. Materials and Plant Protection 10. General stop circuits of standby compressors, high and lowpressure alarms, pressure indicators, and temperatureindicators. Verify validity of relief valve settings.3. Test air dryer units for proper functioning andoperate units through at least one regeneration cycle.Verify operation at maximum flow rates. Verifyappropriate differential pressures and proper operationof pressure switches, high and low pressure alarms,safety and/or relief valves, bypass valves and alarms, andresets.4. Verify by test that the instrument air system willmeet specifications relating to flow, pressure, andtemperature of the product air.5. Verify by test that the system will meet cleanlinessrequirements with respectto oil, water, and particulatematter contained in the product air by analyzing the airat the end of each main feeder line using continuousflow techniques or by the analysis of a discrete sample.6. When redundant components of the instrument airsystem are required, verify by test that the failure or lossof function of one component will not prevent theproper operation of the others.7. Test and check for proper operation allsafety-related instruments, controls, and valves served bythe instrument air system. Verify that all safety-relatedinstruments, controls, and valves served by each branchof the system are properly labeled and that their remotecontrols, indicators, and alarms are correctly identified.Verify by test that the failure of any non-safety-relatedinstruments, controls, and valves served by theinstrument air system or the lines leading thereto willnot jeopardize the safety-related parts of the system.8. Conduct a loss-of-instrument-air-supply test on allbranches of the system simultaneously, if practicable, oron the largest number of branches of the system that canbe adequately managed as follows:a. Prior to the test, place the valves to be tested,except for those valves which fail as is, in a positionother than the failed position. Maintain the rest of theplant in as close to normal operating condition as ispossible. (It should be noted that not all valves can beplaced in the required positions because of operatingprocedure requirements or personnel or equipmentsafety factors.)b. Shut off instrument air supply in a manner thatwould simulate an instrument air pipe break and verifythe movements of the affected components. Also verifythe adequacy of the various feeders or branches tosustain an adequate share of the decaying air supply asrequired by the operational mode; i.e., verify thatbranches of smaller pipe sizes are not starved by flow tobranches of larger capacity.9. Rerun the test outlined in Regulatory Position C.8with the exception that, during this test, shut offinstrument air supply very slowly to simulate the loss ofinstrument air by moisture freezing and plugging themain supply line.10. Rerun the tests outlined in Regulatory Positions C.8'and C.9 with the exception that, during these tests, placethe valves in their normal operating position.11. The results of each test performed in accordancewith Regulatory Positions C.A through C.10 aboveshould be included in the startup report2 which shouldpresent a description of the test, a comparison of testresults predicted by the test procedures, identification ofconditions encountered which were not anticipated,corrective actions, if any, and an evaluation of testresults.See Regulatory Guide 1.16, "Reporting of OperatingInformation," Revision 1, October 1973., Section C.l.a.(1). K1. 80-2