ML19323F183

LER 80-046/01T-0:on 800509,environ Temp Effect on Main Steam Safety Valve Setpoints Not Considered in Design Analysis. Caused by Failure to Consider Environ Temp Variation.Design Evaluation Will Determine Corrective Actions Required

ML19323F183
Person / Time
Site:	Sequoyah
Issue date:	05/22/1980
From:	Maehr S TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19323F178	List: ML19323F177 ML19323F183
References
LER-80-046-01T, LER-80-46-1T, NUDOCS 8005280622
Download: ML19323F183 (2)

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, . ,, Tenn:ssza Valley Authority

.< Sequoyah Nucicar Plant LER SUPPLEMENTAL IUPORMATION SCEG-50-327/ 8046 Technical Specification Involved 6.9.1.12.1 Reported I'nder Technical Specification 6.9.1.12.1 te ci Oc urrence: 5/9/80 Time of occurrenec:

ID.'6 CDST Unit 1 Identit'icatien and Descriptica of_Gecurrence:

A de:cirn ruview discovered that consideratien had net been taken for the effects of varyir.g temperatures in the main steur. valve reorc on tre setpoints of the mair etcam safety valves. Analysis shcwed that veristion in the setpoints could exceed the allovable tolerances of paragraph NC-7641.2 of ASMI Section III code if the valve room tsoperatures ran greater then 120cF or less than 500F, If the roo= tempcratures drtpped below 50"F the possibility exist that auxiliary feed-water systen perforr:ance could be degraded due to increased s can generator prensure.

Conditienc Prior to Occurrence:

Unit 1 in !bde 4 during syste= hestup (<3500f) .

Actica specified in the Technic 01 Specificatica Surveillance ?cquirecents met due to inocerable eculutent.

N/A Apparent Catme of Occurrenec: -

Failure to cer. sider the effects of variaticas in enviren=cutal tc perature on 1 opcning pressure of main stens safety valve precurc=ent specifications or in environnental control systen design tceperature rcnga.

1 Anal:,ais of Occurrence:

No danger to public health and safety.

Corrective Action:

Further analyals is being dcne to detertine if the expected reca temperatures could fall outside the acceptcbic r:nge ar.d if so, what design change would be necessary to maintain it within the neceptabic range (5007 - 120 F) .

Failure Data:

N/A I i

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