05000346/LER-1980-054-03, /03L-0:on 800627,NI-1 Output Failed to Zero During Fuel Assembly Movement.Assembly Removed & Put in Support Rack.Cause Unknown But May Be Intermittent Grounding Problem or Component Failure.Ground Problems Under Investigatio

/03L-0:on 800627,NI-1 Output Failed to Zero During Fuel Assembly Movement.Assembly Removed & Put in Support Rack.Cause Unknown But May Be Intermittent Grounding Problem or Component Failure.Ground Problems Under Investigation

ML19330A570
Person / Time
Site:	Davis Besse
Issue date:	07/23/1980
From:	Werner B TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19330A567	List: 05000346/LER-1980-054-03, /03L-0:on 800627,NI-1 Output Failed to Zero During Fuel Assembly Movement.Assembly Removed & Put in Support Rack.Cause Unknown But May Be Intermittent Grounding Problem or Component Failure.Ground Problems Under Investigatio
References
LER-80-054-03L, LER-80-54-3L, NUDOCS 8007280589
Download: ML19330A570 (2)

LER-1980-054, /03L-0:on 800627,NI-1 Output Failed to Zero During Fuel Assembly Movement.Assembly Removed & Put in Support Rack.Cause Unknown But May Be Intermittent Grounding Problem or Component Failure.Ground Problems Under Investigation

Event date:
Report date:
3461980054R03 - NRC Website

text

NRC FORM 366 U. S. NUCLEAR REGULAT!RY COMMISSION (7 77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

l l

l l

lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) l0 lH lD lB lS l1 l@l 0l 0l 0l 0l 0l 0l 0l0 l0 l0 l0 l@l 4l 1l 1l 1l 1l@!

l l@

7 8 9 LICENSEE CODE 14 15 LICENSE NUMdER 25 26 LICENSE TYPE JO 57 CAT 68 CON'T

[ TIE S$Ry l L l@l 0 l 5 l0 l-l0 l3 l4 l6 @l 01 61 2 l 7 l 8 l l@l 0 l 7 l 2 ] 3 l 8 l O l@

7 8

60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCp PTION AND PROB ABLE CONSEQUENCES h o 2 l(NP-33-80-65) On 6/27/80 at 1007 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.831635e-4 months <br />, the output of NI-1 failed to zero.

At the l

lTTT1 I time, a fuel assembly was being moved, placing the unit in the action statement of I

~lol4l l Technical Specification 3.9.2.

Since the fuel assembly was almost entirely removed l

ITTTl lfrom the core, the assembly was removed and placed in a support rack.

All further I

1016 l l core alterations were stopped. There was no dancer to the health and safety of rhn l

l017 l lpublic or station personnel. Redundant indication was continuous 1v available from I

Io la l lNI-2.

I 7

8 9 80 SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SU8 CODE COMPONENT CODE SUSCCDE SUBCODE l Il Dj@ W@ W@ lI lN lS lT lR lU l@ [Ej @ (_Z_j @

o 9 7

8 9

10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LER/RO EVENT YE AR R EPORT NO.

CODE TYPE N O.

@ gu l8 l0 l l-l l Ol 5l 4l l/l l 0l 3l lLl l-l l0 l RE

_ 21 22 23 24 26 27 N

N 30 31 32

/N AC N

ON PL NT ME HOURS 22 S8 IT FORP 8.

SUPPLI MANUFA TURER F l@F l@

lZl@

IZi@

10101010 l lYl@

W@

lZ l@

l Zl 9l 9l 91@

33 34 35 36 37 40 41 42 43 44 47 CAUSE OESCRIPTION AND CORRECTIVE ACTIONS h g [The exact cause is unknown but may be due to an intermittent eroundine problem or com-1 i i iponent failure.

Station instrument ground problems are beine investignend Imanr m I

179-429.

NI-l was checked under Maintenance Work Order IC-479-80 and found to be

, 2 g l operating normally.

ST 5091.01 was performed satisfactorily and NI-l s.

lared l operable at 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br />.

l i 4 7

8 9 80 SA S

% POWER OTHER STATUS iO RY DISCOVERY DESCRIPTION W lH l@ l 0 l 0 l 0 l@l NA l

lAl@lControlRoomIndication l

A TIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELE ASE 1 6 lZ l @ W@l NA l

l NA l

7 8 9 to 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE

DESCRIPTION

L'J.2I lo le 10 l@lz l@l NA l

So

' PERSONd'imU4ES DESCRiPTiO~@

NUMBER l0l0l0l@l NA l

t a 8 9 11 12 80 LOSS OF OR DAMAGE To FACILITY TY'E

DESCRIPTION

lZ l@l NA l

i 9 7

8 9 10 80 PUBL ICITT 8007sp 5%9 "S"

ISSUED E5CRIPTION

[1,[0_l lN l(m NA l

l l l l l l l l l l l l l :3 l7 8 9 I"

68 69 80 ;;;

DVR 80-104 ME OF PREPARER PHONE:

TOLEDO EDISON COMPANY DAVIS-8 ESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-80-65 DATE OF EVENT: June 27, 1980 FACILITY: Davis Besse Unit 1 IDENTIFICATION OF OCCURRENCE:

Source Range Nuclear Instrumentation Channel 2 (NI-1)

Failure Conditions Prior to Occurrence: The unit was in Mode 6 with Power (MWT) = 0 and Lead (Gross MWE) = 0.

Drscription of Occurrence: On June 27, 1980 at about 1007 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.831635e-4 months <br />, the output of NI-l failed to zero. At the time a fuel assembly was in the process of being moved and was approximately 3/4 of.the way out of the core. This placed the unit in the action statement of-Technical Specification 3.9.2 which requires all core alterations to be suspended until both source range channels are operable.

Since the fuel assembly baing moved was almost entirely removed from the core, the Shif t Supervisor determined it would be' safer to complete the fuel assembly removal. Removing the assembly removes positive reactivity from the core. To have reinserted the assembly would have added positive reactivity to the core. The assembly was removed and placed in a support rack in the refueling canal.

All further core alterations were stopped.

t Designation of Apparent Cause of Occurrence: The exact cause of this occurrence is I

unknown, but has the characteristics of being an intermittent grounding problem, or intermittent failure of an unknown compdnent.

Station instrument ground problems are currently being investigated under Facility Change. Request (FCR)79-429.

Analysis of Occurrence: There was no danger to the health and safety of the public cr to station personnel. Redundant indication was continuously available from NI-2.

Corrective Action

Maintenance Work Order (MWO) IC-479-80 was issued to trouble-ghoot and repair NI-1.

The channel was put in test and found to operate normally.

The power supply was then de-energized, and-the cables checked for shorts and opens.

The preamplifier was opened,and inspected for moisture or heat related problems. All inspection results were negative, and the channel re-energized. When power was res-tored, the channel was found'to be operating normally. ST 5091.01, Source Range Functional Check, was performed and the channel declared operable at 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br />, thus removing the unit from the action statement of Technical Specification 3.9.2.

Data currently being taken under FCR 79-429 concerning station grounding problems will

+

ba evaluated.

If the problem re-occurs, portions of the FCR test involving source range channel 2 will again be performed in an attempt to isolate the intermittent problem.

Failure Data: There have been several previous similar failures of NI-1.

See Licensee' Event. Reports NP-33-77-79, NP-33-77-88, NP-33-77-100, NP-33-78-110, NP-33-79-87,

. cad NP-33-79-107.

LER #80-054