ML19256A864

LER 78-124/03L-0 on 781216:during Surveillance testing,13 of 18 Main Steam Safety Valves Failed to Be within +/-17 of Design Setpoint,Apparently Caused by Change in Ambient Conditions

ML19256A864
Person / Time
Site:	Davis Besse
Issue date:	01/11/1979
From:	Brown R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19256A863	List: ML19256A862 ML19256A864
References
LER-78-124-03L, LER-78-124-3L, NUDOCS 7901160248
Download: ML19256A864 (3)

Text

..

NRC FORM 366 (7 771

- LICENSEE EVENT REPORT (PLEASE PRINT OR TYPE ALL REQUf RED INFORMATION)

CONTROL BLOCK: l f

l l l l l lh 0

l l@ .

)

o 1 8 9 l 0 l H l D l B l S l 1 l@l 0l Ol -l 0l 0l Nl Pl Fl -l O! 3l@(4 l1 l1 Il l1 l@

LICENSEE CODE 14 15 LICEME NuYSER 25 26 LICENSE TYPE JO $ 7 % A T $8 e

l

CON'T

" I 0 5 l0 l ;O l3 l4 j6 gl1 l2 l1 l6 l7 l8 l@l 0l lj 1l 1l 7 l 9tioj@  ;

7 0 i 8

57RC"'l'l@l 60 61 I

OGCKET'd/8ER tM 63 Eb ENT DATE 74 75 REPORT D ATE during the perf omance of surveillance testing,13 of the 18 Main Steam l EVENT DESCRIPTION AP.D PROR ASLE CONSEQUENCES h

[o Jyl [ On 12/16/78, This placed the unitj Safety Valves (MSSV) f ailed to be within 117, of design setpoint.

l o 13 ] 1 ment of T.S. 3.7.1.1, requiring the valves to be restored to operaq o ,i l in the Action Sta6 to be reduced, or be within hot Shutdown; go ticnal status or the high flux trip setpoint 3 l The unit was in the process of shutdowq o e [ in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Cold Shutdown within 30 hours.

There was no danger to the health and l o 7 l and was in Cold Shutdown within 30 hours.

l (NP-33-78-145) o 8 [ sjf ety of the public or to unit personnel. 80 COVP. VALVE 7 8 9 CAUSE CAUSE SUSCODE SYSTEM COYPONENT CODE SUSCODE CODE CODE SLSCODE 10191 I c Ic j@ y@ lx l@ l V l A f3 l L l V l E l X l@ y@ [20B_J @18 19 9 10 11 12 REVISION 7 8 OCCURREP.CE REFORT SEQUE N TI AL CODE TYPE No.

@ 4E,P,g LER RO

,_ EVENT YE AR 17l8l L-l REPORT NO.

l1 l2 l 4 26l ] ,,, - l l0 l3 l 29 lL l 30 l_l 31

{

32 24 27 28

_ 23 22 23 FOR1 8. S PLI MAN FA T nER S B*IT D AKE gggg ATC O PLANT

• T HOURS l 0l Cl 0l DJ l Y lg l42 YlQ l43N l@ lDl2l4l3l@

44 47 33 34 l3h Z lg lMZ ]@ 31 40 41

'

CAUSE DESCRIPTION AND CCRRECTIVE ACTIONS h ambien t l i o l The apparent cause of the variation is believed to be due to the change in y

The ambient umperature of the MSSVs and the MSSV roca during the l: lil l conditions.

l 1978. The valves were adjustell, j,l7y l12/16/78 test was 1cuer than the test performed in Ju y Several valves were found to be leaking j l i 13 l [ tested and de:lared operable on 12/16/78.

J iil4i 1 and were retaired and retested on 12/30/78. 80 7 8 9 ISCC RY DISCOVERY DESCRIPTION

• .PONER OTH ER ST ATUS ST S l NA j lBl@l Surveillance Test l1 l 5.1 l Cl@ l 0 l 0 l 0 l@l _

ACT;viT V CO TENT LOCATION OF RELE ASE RELE ASED CF PELE ASE AYOUNT OF ACTivlTY l NA I 6 lZl NA 44 l l 45 80 7 8 9 10 11 PERSONNEL EXPOSLRES '

NU'/B E R TYPE D E SCRIPTION l 1 7 l0 l0 0 lhl Zl@l NA PE RSON*.E L INJU ES NUVBER DESCRtPTION j i a 0 10 0 @ l 12NA 80 7 8 9 11 LO3S OF CR D AY AGE TO F ACILITY TYPE C E SC A LP TION j 1 9 l NA 80 7 3 9 IU *

!! St.; E DE CRIPTION I IIII IIIIIIIl}

I:fol IN Ihl NA b P 08 69 80 5

'

R 9 419-259-5000, Ext. 250 2 DVR 78-186 N7 A,,9 01 16 0 2 dard A. Brown E OF PREPARER PHONE: ,

.

. . 4 TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-78-145 DATE OF EVENT: December 16, 1978 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Main Steam Safety Valves were tested and found to be outside of i 1% Design Setpoint Range.

,

e, I

The unit was in Mode 3 with Power (MWT) = 0, and Ccnditions Prior to Occurrence:

Load (Gross MWE) = 0.

i Description of Occurrence: During the performance of ST 5070.01, " Main Steam Safety Valves Setpoint Test", thirteen of the eighteen valves during the initial lif t were found to be outside of 11% design setpoint range.

This placed the unit in the Action Statement of Technical Specification 3.7.1.1 which requires valves to be operable in Modes 1, 2, and 3. The Action Statement j requires the valves to be restored to operable status within four hours or the high flux trip setpoint be reduced or the unit be in Hot Shutdown (Mode 4) within six hours and Cold Shutdown within thirty hours.

The unit cntered planned Hot Shutdown at 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br /> on December 16, 1978, and planned Cold Shutdown at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> on December 16, 1978.

Designation of Apparent Cause of Occurrence: The apparent cause of the slight varia-tion in relief valve lif t pressure is believed to be due to changing ambient condi-tions at the location of the valves. The ambient conditions at the location of the valves were different from the last test conducted in July,1978. 1

'

The ambient temperature of the main steam saiety valves and safety valve room during the December 1978 test was lower than the ambient temperature during the last test perf ormed in July,1978.

Analysis of Occurrence _: There was no danger to the health and safety of the public or to unit personnel. The unit was being shutdown at the time of the conduct of the test. The valves would still have served their intended function of relieving pres-sure if a unit trip had occurred.

Corrective Action: Tne valves were adjusted and retested per Maintenance Work Order 78-2888 and the last was declared operable by 1140 hours0.0132 days <br />0.317 hours <br />0.00188 weeks <br />4.3377e-4 months <br /> on December 16, 1978.

Several valves were observed leaking af ter the test. Valves Al, A2, A7, B1 and B2 were disassembled, repaired and reassembled per Maintenance Work Order 78-2897 and were tested on December 30, 1978.

LER #78-124

,

. . s'

'

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLDEtTTAL INFORMATION FOR LER NP-33-78-145

!'

Facility Change Request (FCR)77-322 and FCR 77-319 have been issued for implemen-tation to install hoods on the main steam safety valve exhaust stack for protec-tion during the winter months and provide ventilation during the summer months.

Both FCRs will help control mbient conditions. Temporary ventilation will be provided if ambient temperature becomes excessive.

Failure Data: There has been one previously reported occurrence of incorrect safety valve lif t setpoints. See Licensee Event Report h?-33-77-117.

LER #78-124

,

.

e