05000327/LER-1982-070

LER 82-070/01T-0:on 820618,discovered Possible Inoperability of Containment Sump Level Instrument Loops in Event of Loca.Possibly Caused by Increased Temps Rupturing Sensor Bellows.Procedures Revised

ML20054M110
Person / Time
Site:	Sequoyah
Issue date:	07/01/1982
From:	Harding M, Rogers H TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20042C744	List: 05000327/LER-1982-070 ML20042C743
References
LER-82-070-01T, NUDOCS 8207090257
Download: ML20054M110 (2)

LER-2082-070,

Event date:
Report date:
3272082070R00 - NRC Website

text

.

7 yqq.. w-  %

( , e.,

LICENSEE EVENT REPORT (hAAlt . .I' p.

2 .

COfJTROL DLOCK: ) l l l l l l 6 (PLE ASE PRINT On TYPE ALL REQUIRED INFORMATION)

JPlo l1l8 9lT lNLICENSEE lS lNCODE !P'!1 I4!h__0 15 l O ! -l 0LIGEN5E l 0 l NUUSEH 0 l 0 l 0 l- l0 l025 l@! 26 4 LICENSE l 1 l 1TYPE l 1JOl 1 l@[ l l Q, 5 7 C a t go, I CON'T * *

,2a, lolil 8

3{ ",lL60 @l0 15 l0 00CKE 69 l0 l0l3l2l7 T NuvoEH hl0 fr36911 lg 68 l 8 l 2 l@l 0l 7 l 0 l 118 l 2 J@

EVENT OATE 74 76

' REPORT DATE 30

' EVENT DESCRIPTION AND PD00ABLE CONSEQUENCES h IT'lT} l With units 1 & 2 in mode l'(100% power. 578 decrees F. 2235 nsid at 1425 CST on

[ 0131 l 06/18/82, the containment sump level instrument loops have the possibility of beint Io l4 l l inoperable in the event of a LOCA due to 1 icreased temperatures run'turine ti sense a..

lo Is] l bellows. This event is reportable under section 6.9.1.12.1 of the technical l o is I l~speci ficatiotis. There 'was no ef fect upon public heal th and safetv . Previous

..y. . . , .

~

l 0 l 7] l ~ occurrences - none. .

Io ia l l SYSTEM CAUSE_ C AUS E CODE COMP. VatyE CODE' SUSCODE COM'ONE N T CODE SUSCOOE SUSCOOE loI9l 2 3 lS lF lh Wh l A lh l1l Nl S { T IR lU lh Wh h h 9 to 13 12 13 .

18 19 20

'f 0UENTI AL OCCunnENCE ' REPORT R E VISION LER EVENT YE AR RE Pon T No. IODE TYPE NO.

@ ,ag/AO ar 1812I

~

,_ 21, 22 l_J 2J l 01 71 01 24 26 l/l 27 10 l t i ITI l-l 10I 28 29 33 3 32 ET A T r O rLaNT T U HOURS 5 8 lit o F Of 41 UB. SUPPL 1 MAN FACTUI.

W JJ @lxl@ JbIzl@

34 lzl@ l 0l ol 0101 IVl@

36 31 40 41 l42N l@ lL l@. lB l0l8 43 44 CAUSE DESCRIPTION AND CORGECTIVE ACTIONS h .

li lo l l It was determined, during evaluations made of the level transmitters, that the i l sealed water filled capillary could possibly. fl6sh to steam in the event of a LOCA .

t?..

4 l T'M I nd rupture the sensor bellows. This would cause a loss of automatic switchover sa..

3g , g 3 g [ from the RWST suction to containment sump suctlon for ECCS~ equi'pment. It could 'als-

?.ig.~ .

/[gl provide erroneous indication to the control room operators. Measures have been tak

. .-s. .s g to 17p~lement a manual switchover tollowing a LUGA.

~ ge - r At.tLI1Y 'y MEfleOO OF

j. S T All t's "L POvvER OT84E n status DISCOvt n Y DISCOVEnv DESCRIPTION 32 lii$i L Ej@ l 1l 0 l 0 l@l NA l l C l@l Equipment evaluation e A TivlTV' CO TENT RELEASED Or nELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE

' a 1t.yI, ,

• a 9 LzJ @ 10LzJOI 19 NA 44 l l 45 NA 4g. pen 50NNEL EXPO 5uREs

.'* NUMBER TYPE DESCRIPTf 0N

-lTTil

\ 7, . 8 9 1010 LOJ@l z l@l 11 12 13 NA gj.., PE RSONNE L INJUnlES NOV8tR DESCRtPTION li 181 a o10101 o l@li2 si NA LOS$ OF OR D AM AGE TO FACillTY TYPE DESCRIPTION Il2 198I 9LzJ@lto NA essuf otsCRiPfiONO ""U 8207090257 820701 '

b7 8 9 hl 10 n (DRADOCK 05000327 PDR l

sa og lJlIIfIII1l N'ame of FrenRro,- 11. R. Rogers /M. R. Harding Phone (615) 751-0349 y -@

Sequoyah Nuclear Plant 1

e e

e LER SUPPLEMENTAL INFORMATION SQRO-50-327/82070 Technical Specification Involved: 3.3.2.1 6 3.3.3.7 Reported Under Technical Specification: 6.9.1.12.1 Date of Occurrence: 06/18/82 Time of Occurrence: 1425 CST Identification and Description of Occurrence:

Units 1 and 2 containment sump level transmitters LT-63-176, 177, 178 and 179 could have been inoperable in the event of a LOCA causing a loss of automatic switchover from the RWST to the containment sump. The sump level is also identified as accident monitoring instrumentation which under the postulated accident conditions could have been inoperable.

Conditions Prior to Occurrenc.c:

Units 1 and 2 in mode 1 at 100% reactor trip power.

Apparent Cause of Occurrence:

During evaluations made of the level transmitters, it was determined that the sealed water-filled capillary could possibly flash to steam in the event of increased temperatures during a LOCA. The rapid increase of temperature / pressure in the reference leg could possibly rupture the sensor bellows resulting in a failure of the transmitter.

Analysis of Occurrence:

A ruptured bellows would cause the fill fluid (water) to be forced out of the sence line due tc steam pressure at the top of the sense line. As a result, the sump level transmitter would see a dif ferential pressure of 0 psid. Since the transmitters are calibrated to indicate approximately 18 feet level in the sump, with 0 differential pressure across the transmitter, the channel indication could lead to inappropriate operator action. Also, if these events occurred, there would be a loss of the capability to automatically switchover from the RWST suction to containment sump suction for ECCS equipment following a LOCA.

Corrective Action:

The containment sump level transmitter bistables have been placed in the bypassed (test) condition. This removes the capability of automatic switchover and requires a manual switchover by operators. Applicable procedures have been revised to reflect this required operator action and appropriate Operations personnel informed of this change. Temporary technical specification revisions to LCOs 3.3.2.1 and 3.3.3.7 have also been made to delete the requirement for automatic switchover.

Plans are being made to refill the scaled legs with a silicone oil to prevent flashing at elevated temperatures during a LOCA. After completion, the capability of automatic switchover will be reinstated. This work is scheduled to be completed by July 18, 1982.

Failure Data:

None.

_