05000346/LER-1979-018-03, /03L-0:on 790130,valves SP17A2 & SP17B2 Lifted Below Setpoint Range & Declared Inoperable.Caused by Loose Spindle on Main Steam Line Code Safety Valve SP17A2.Valve SP17A2 Gagged & SP17B2 Tested Satisfactorily

/03L-0:on 790130,valves SP17A2 & SP17B2 Lifted Below Setpoint Range & Declared Inoperable.Caused by Loose Spindle on Main Steam Line Code Safety Valve SP17A2.Valve SP17A2 Gagged & SP17B2 Tested Satisfactorily

ML19282A607
Person / Time
Site:	Davis Besse
Issue date:	02/26/1979
From:	Brown R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19282A606	List: 05000346/LER-1979-018, Forwards LER 79-018/03L-0 05000346/LER-1979-018-03, /03L-0:on 790130,valves SP17A2 & SP17B2 Lifted Below Setpoint Range & Declared Inoperable.Caused by Loose Spindle on Main Steam Line Code Safety Valve SP17A2.Valve SP17A2 Gagged & SP17B2 Tested Satisfactorily
References
LER-79-018-03L, LER-79-18-3L, NP-33-79-23, NUDOCS 7903050176
Download: ML19282A607 (3)

LER-1979-018, /03L-0:on 790130,valves SP17A2 & SP17B2 Lifted Below Setpoint Range & Declared Inoperable.Caused by Loose Spindle on Main Steam Line Code Safety Valve SP17A2.Valve SP17A2 Gagged & SP17B2 Tested Satisfactorily

Event date:
Report date:
3461979018R03 - NRC Website

text

NRC FORM 366 (7 77)

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8 60 61 COCKET NU'.9E R EVENT DESCRIPTION AND PROBABLE CONSEQUENCES bio lo121l On 1/29/79 load swings resulted in tee lifting of Main Steam Line Code Safety Valves g

SPl7A2 and SPl7B2. On 1/30/79, it was detemined that valves SPl7A2 and SPl7B2 lif tedj gg,3, g below their setpoint range and were declared inoperable. This placed the unit in the g

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The high flux setpoints were reduced to 92.6% of rated thermal power.

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danger to the health and safety of the public or unit personnel. The remaining eightj g

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code safety valves per main steam line are operable.

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l i l o l l Main Steam Line Code Safety Valve SPl7A2 was found to have a loose spindle and was Q l gagged. Valve SPl7B2 was tested, f ound satisfactory, and declared operable on I

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60. E DVR 79-027 PHONE:

NAME OF PREPARER

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLDfENTAL INFORMATION FOR LER NP-33-79-23 DATE OF EVENT:

January 30, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Main Steam Safety Valves SPl7A2 and SPl7B2 declared inoperable.

Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2550, and Load (Gross MWE) = 825.

Description of Occurrence: On January 29, 1979, during a unit startup, load swings re-sulted in the lif ting of Main Steam Line Code Safety Valves SP17A2 and SPl7B2.

On Jan-uary 30,1979, during the review of the transient monitor data, it was determined that valves SPl7A2 and SPl7B2 lif ted below their setpoint range, 1050 psig + 1%.

At 1645 hours0.019 days <br />0.457 hours <br />0.00272 weeks <br />6.259225e-4 months <br />, valves SPl7A2 and SP17B2 were declared inoperable. This placed the unit in the Action Statement of Technical Specification 3.7.1.1, which requires that with one or more main steam line code valves inoperable in Modes 1, 2, and 3, operation may proceed provided that within four hours, either the inoperable valve (s) is restored te operable status or the high flux trip setpoint is reduced per Table 3.7-1.

Unit power was reduced ta less thaa 90% power.

At 1715 hours0.0198 days <br />0.476 hours <br />0.00284 weeks <br />6.525575e-4 months <br />, the high flux setpoints were reduced to 92.6% of rated thermal power.

Designation of Apparent Cause of Occurrence: Main Steam Line Code Safety Valve SP17A2 was f ound to have a loose spindle and was gagged. Valve SPl7B2 was tested, found satis-factory, and declared operable on February 13, 1979.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. The remaining eight code saf ety valves per main steam line are operable.

These valves have the capacity to relieve steam pressure in case of a unit trip.

Corrective Action

Maintenance Work Order 79-1408 was issued to retest the required main steam safety valves. On February 13, 1979, SP17B2 was tested, found to be within the acceptable tolerance range, and was declared operable by 2330 hours0.027 days <br />0.647 hours <br />0.00385 weeks <br />8.86565e-4 months <br />.

SPl7A2 lif ted at 955 psig when tested. When attempting to adjust the valve, it was observed that the top of the spindle was loose. No further attempts were made to adjust the valve and the valve was gagged, rendering it inoperable by 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> on February 14, 1979.

SPl7A2 will be disassembled and repaired at the next suitable unit shutdown.

LER #79-018

e TOLEDO EDISON C0:IPANY

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DAVIS-LESSE NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLEMENTAL INFORMATION FOR LER NP-33-79-23 Prior occurrences of main steam line code safety valves drif ting from Failure Data:

their normal setpoints were previously reported in Licensee Event Reports NP-33-77-117 and NP-33-78-145.

LER #79-018 e