Information Notice 1979-08, Interconnection of Contaminated Systems With Service Air Systems Used As Source of Breathing Air

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Interconnection of Contaminated Systems With Service Air Systems Used As Source of Breathing Air
ML031180148
Person / Time
Site: Indian Point, 05000000
Issue date: 03/28/1979
Revision: 0
From:
NRC/IE
To:
References
IN-79-008, NUDOCS 7904300481
Download: ML031180148 (3)


UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555M4rch 28, 1979IE Information Notice No. 79-08INTERCONNECTION OF CONTAMINATED SYSTEMS WITH SERVICE AIR SYSTEMS USED AS'THE SOURCE OF BREATHING AIR

Description of Circumstances

This Information Notice describes an event which occurred at the Peach:-Bottom Nuclear Power station; however, the generic implications may beapplicable to other power reactors and selected fuel cycle facilities.On October 4, 1978, the Philadelphia Electric Company (PECO) reportedthat, on two occasions at Unit 2, contamination had leaked from theradwaste system to a system used to provide the plant source of breathingair. The leakage occurred through an interconnection of the radwaste.system with the plant breathing air source. PECO established that nopersonnel were subjected to contaminated breathing air as a result ofthis leakage.One of the functions of the service air system at Peach Bottom is toprovide a source of breathing air for personnel using supplied airrespiratory protective equipment. By means of an interconnection to theradwaste system, the facility also uses the service air system to pro-vide a source of compressed air during the backwash cycle of thedemineralizer filter element. The compressed air provides the motiveforce for reverse water flow through the filter element and was beingused to perform this function when the two incidents occurred. Liquidfrom the radwaste system leaked past a check valve and a process valve.PECO determined by analysis of liquid samples that contamination hadleaked into the service air system. Valves in the leakage path weresubsequently dismantled and examined. The examinations revealed thepresence of dirt deposits in the check valve and air operated ballvalve. PECO attributes the specific cause of the leakage to these dirtdeposits which prevented the proper seating of the valves.NRC contacts with other operating power reactors have indicated thatother facilities also use service air as a source of breathing air. Inseveral cases, the service air system is physically interconnected toother systems which carry radioactive material and relies on valves orother barriers to prevent contamination of the plant source of breathingair.7904300481 IE Information Notice No. 79-08 March 28, 1979, t NJREG-0041, "Manual of Respiratory Protection Against Airborne RadioactiveMaterials," which supplements the stipulations of Regulatory Guide 8.15,states in Section 9.8, "A separate breathing air supply and distributionsystem shall be used. The ordinary plant supply of compressed air inany building shall not be used for breathing purposes...unless it hasbeen specifically modified and properly adapted for such use and specifi-cally approved for this purpose by the qualified person supervising therespiratory protective equipment program."At those facilities where service air is used as a source of breathingair, certain precautions can be taken to minimize the potential of aproblem similar to the one described. By review of the service airsystem and as-built (or design) drawings,. interconnections between con-taminated systems and the source of breathing air can be identified.Where interconnections are identified, the design should assure thatadequate separation is provided. In addition, operating proceduresshould provide for controls to prevent contamination of the breathingair source.No specific action or written response to this Information Notice isrequired. If you desire additional information regarding this matter,contact the Director of the appropriate NRC Regional Offic IE InformationMarch 28, 1979Notice No. 79-08LISTING OF 1E INFORMATION NOTICESISSUED IN 1979Information-Notice No.SubjectDateIssued79-0179-0279-0379-0479-05Bergen-Paterson HydraulicShock and Sway ArrestorAttempted Extortion -Low Enriched UraniumLimitorque Valve GearedLimit Switch LubricantDegradation ofEngineeredSafety FeaturesUse of Improper Materialsin Safety-Related ComponentsStress Analysis ofSafety-Related PipingRupture of Radwaste TanksInterconnection ofContaminated Systems withService Air Systems UsedAs the Source of BreathingAir2/2/792/2/792/9/7979-06Issued ToAll power reactorfacilities with anOL or a CPAll Fuel FacilitiesAll power reactorfacilities with anOL or a CP2/16/79 All power reactorfacilities with anOL or a CP3/21/79 All power reactorfacilities with anOL or CP3/23/79 All Holders ofReactor OL or CP3/26/79 All power reactorfacilities with anOL or CP3/28/79, All power reactorfacilities with anOL and Pu Processingfuel facilities79-0779-08