ML20206G466

SER Supporting Employee Concern Element Rept EN 229.6(B), Lack of Valves in Sampling & Water Quality Sys

ML20206G466
Person / Time
Site:	Sequoyah
Issue date:	11/04/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
To:
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References
NUDOCS 8811220291
Download: ML20206G466 (2)

Text

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SAFETY EvA'.UATION REPOPT BY THE OFFICE OF SPECIAL PROJECTS EMFLOYEE CONCERN ELEMENT REPORT EN 229.6(B)

LACK OF VALVES IN SAMPLING AND WATER QUAllTY SYSTEM TENNESSEE VALLEY AUTHORITY SE000YAH iTCLEAR POWEC. PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 1.0 !NTPODUCTION A cerce-r was expressed at Watts Ear Nuclear Plent (kBN) t, hat Water Quality Monitoring Syster ('3) nay centain radioactive materials under certain accident conditiers. In addition, the system lacks isolation ard drain valves for 4 centrolled efiluent rareval. This concern is applicable to Sec;uoyah Nuclear Plant (SCM because tFa primary anc secondary process system (Systen 43), and the physical laycut at SON are essentially the same at those et WEN.

2.0 EVAlt

ATION Category: Engireering (22900)

Subcategory: Instrurentation ard Control oesign Elenent: Lack cf Valves in Sampling ord Water Quality System Employeo Concern: IN-85-348-003 The basis for Elerent Report EN 229.S(S) SQN Rev. O, c'ated December 30,19C6, j is Secueyah Erployee Concern IN-85-348-003 which states:

"Unit G. Elev. 713' pipe chase Syster 43 Water Quality Penitoring - has the cotartial to contain radioactively contaminated wper under postulated accident g corcitions. System does not contain isclation/ drain valves fnr controllec cao crawing of effluent under routine /erergency maintenance corditions."

38 TVA's evaluat'on ef concern corsisted of:

om (a) establishir9 the potential for contanination in Syster 43 "Sampling and i g Water Cuality Meritering,"

cag 8q (t' review 4rc flow diagra.rr to veri #y extraction capability cf potentially 0j

. carter'ratec ccetiert c' Sytter 43 in pice chasa,

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$$(L 'C' *";c1PC 3; 1 *.8

• O c0t87.tillly Co"ta* nated ef#iuents to prefer deSarta-iratter facility prior to release, and (d) deterrinirg potFntial expcsures to operators taking such act' Ors.

In regard to potential for contamination, System 43 does handle radioactive liquid in the pipe chase. The pipe chase is an irregularly shaped rocr which lies adjacent to the het sample room and abuts tre cutside wall of the Peactor Evildirg. Radioactive ramples pass through the pipe chase in oiping fecr the primary process systems withir the containment to the sampling system equiprert i,

in the het sample recm.

Isolation capability is provided by air-operated isolation valves near the sample pt. int and inside ard rutside containnent for sample lines originating inside centainrert. Manual isolation valves are prnvided on sarple lines originating cutside containnent, except for the volume control tank vent and RHR niniflew lines which have air cperated isolation valves. The locatinn of isclation valves for line. :originating cutside centainment is also rear the sample point. There are also isolation valves at the inlet of each sarple lire te the sarple cubicles boron renitors ard gas analyzer. Additienal isolatior valves are provided in cubicles IA and 2A Pnd at the gas analyzer to perrit remeval of sarple cylirders.

In recard te drairage cacability. System 43 pipirg in the pipe chase is drained thrcugh the sarple cubicles, boron menitors, and gas analyzer in the hot sarple room. Modules hardling primary system samples are drained to the CVCS volume certrol tank which ::ernitt recyling raterial not recoved from the syster in a sample cylincer. *he ether endules are draired to the cubicle sinks ca to the building drairage system directly fecm which it will tot be released without proper roritering and treatrent.

Additieral precautiers have been taken to reduce rar.'itien exposure to persorrel. These acditional precautions included ir " aased transit tire to provide delay ef N-16. lead shielding behind the frer; plate of the cubicles 6nd availability of lead shielding sample cylinders. Furtbarrore, access to tre hot sample reem and pipe chase is controlled by locked deers and is under administretive bealth physics centrol.

3.0 CONCLJS'CNS The p3** cf the corcern regarding the potentia' for Systen 43 piping to centain racicactive raterial is true; this is by design, howeser. The systen was fcurd to contain isolation valves, as well as valves to control tha drawing of e'fluents under both operating and raintenance conditfors. TVA has al to taken precautions to maintain personrel exposure levels to radicactivity within acceptable limits.

The NDC staff concludas that TVA's investigetien and *esolution of the conceens described in Elerent Report M9.6(B) were adequate. 'in 'urther NCC raview is required.