IR 05000409/1986006

Insp Rept 50-409/86-06 on 860407-0613.No Violations Noted. Major Areas Inspected:Operational Safety Verification,Maint Activities,Ler Followup,Plant Trips,Forced Manual Shutdowns & Startup Testing - Refueling

ML20202A913
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	06/26/1986
From:	Boyd D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20202A852	List: IR 05000409/1986006 ML20202A848
References
50-409-86-06, 50-409-86-6, NUDOCS 8607100156
Download: ML20202A913 (14)

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.U. S. NUCLEAR REGULATORY COMMISSION .s

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, REGION III

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Report No. 50-409/86006(DRP) ,

. Docket No. 50-409 .

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Li ense No. DPR-45

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, Licensee: Dairyland Power Cooperative - '

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2615 East Avenue - South La Crosse, WI 54601 .

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Facility Nase: La Crosse Boiling Water Reactor .

, Inspection At.: 'La Crosse Site, Genoa, WI

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InspectionConductei: April 7 through June 13, 1986 .

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Inspector: I. Villalva

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Approved By: D. C. B'oy , hief .

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, Reactor Proje' cts Section 2D Date

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Inspection Summary ,

Inspection from April 7 through June 13, 1986 (Report No. 50-409/86006(DRP))

Areas Inspected: Routine, unannounced inspection by the resident inspector

.of Operational Safety Verification; Maintehance Activities; Licensee Event a-Reports Followup; Plant Trips and Forced. Manual-Shutdowns; Startup Testing - '

- Refueling;'and Open Item Results: No violations o'f'~NRC aequirements were note . t

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DETAILS

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' Persons Contacte'd ,

• J. Parkyn, Plant Superintendent

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• G. Boyd, Operations Supervisor .

• L. Kelley, Assistant to Operations Supervisor .

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L. Nelson, Health and Safety Supervisor ,

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, R. Wery, Q0ality Assurance Supervisor

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S. Raffety, Reactor Engineer '

P. Bronk, Nuclear Engineer -

• L. Goodman, Operations Engineer '

R. Biimer, Electrical Engineer *

D. Rybarik, Mechanical Engineer *

. The inspector also intervic'wed other licensce personnel during the course of the inspectio *

• Denotes tho'se attending exit interviews during the-inspection period.

, , Operational Safety Verification'

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The inspector" observed control room operations, reviewed applicable logs and conducted discussions with control room operators during the period of this report. The inspector verified the operability of selected emergency systems, reviewed tagou.t records and verified proper return to service of affected components. ' Tours of the reactor building, turbine building, and cribhouse were conducted to observe plant equipment conditions, including potential fire hazards, fluid leaks, and excessive vibrations and to verify that maintenance requests had been initiated f equipment in need of maintenance. The inspector by observation and

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direct interview verified that the physical security plan was being .

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implemented in accdrdance with the station security pla ,, , . . .

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-The inspector obs'erved. plant housekeeping / cleanliness conditions an . verified implementation of radiation protection controls. The inspector, - '

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walked down the accessible portions of the ' emergency core spray systems

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to verify operabilit ,

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These reviews and observations were conducted to verify that facility

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operations were in conformance with the requirements established under-technical specifications, 10 CFR, and administrative procedur ~

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- Maintenance Activities -

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Station maintenance activities especially those conducted during the-

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refueling outage, of safety related systems and components listed s belo# were observed / reviewed to ascertain that they were co'n ducted in

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, ,accordance with approved procedures, regulatory guides and industry codes or stand'ards and in conformance;with' te~chnical specification '

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The following items were c'onsidered during this review: the limiting

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conditions for operation were met while components or systems were -

removed from service; approvals were obtained prior to initiating the

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work; activities were accomplished using approved procedures and were inspected as applicable; functional testing and/or calibrations were .

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performed prior to returning components or systems to service; quality control records were maintained; activities were accomplished by qualified personnel; parts' and materials used were properly certified; radiological controls were implemented; and, fire prevention controls were implemente Work requests were reviewed to determine status of outstanding jobs and to assure'that priority i.s assigned to safety related equipment maintenance which may affect system performanc ~

Maintenance activities on the following systems or compone'ts n were observed / reviewed: work on the shutdown condenser valves; relocating Overhead Storage Tank Piping because of proximity to high energy lines; -

installation of a turbocharger on the 1A Alternate Core Spray Diesel;

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relocating the starting batteries for the IB High Pressure Service Water

. Diesel (an Appendix R modification); Inservice Inspection Test of the Alternate Core Spray Valves and subsequent disassembly, cleaning and lapping both the inboard and outboard valves because they failed their Type C leakage test; safety valve adjustments; replacement of inner door

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upper handwheel shaft seal; and replacement of IC Static Inverte Following completion of maintenance on the turbocharger on the 1A Diesel, 4 the relocation of the.0ST piping and installation of IC Static Inverter, the inspector verified they had been returned to service properl . -

, L_icensee Event Reports Followup Through direct observations, discussions with licensee personnel, and .

review of records,.the followin.g event reports were reviewed to determine that reportability requirements were fulfilled, immediate corrective action was accomplished, and corrective-action to prevent recurrence had .

. been accomplished in accordance with technical specification . (Closed) LER 86-04: Monitored Discharge o'f Unsampled Waste Water Tank with Analyzcd Waste Water Tank. On January 13, 1986, the 3000

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' Gallon Waste T.ank (GWT) in the turbine building was being discharged to the river. At 1640, the auxiliary operator noticed that the ~

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. level in the 4500 GWT had decreased from 23% to 14%.to approximately ,

1300 gallons. The turbine building drain system was lined up to the 4500 GWT, therefor.e, the level should have increased. The 3000 GWT level had decreased to 10%. As a result of these readings the operator secured the discharge to the rive '

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This event was due to the failure of a suction valve ,from'the 4500-GWT suction 'to the 1A Waste Water Pump. . The valve. failed such that it remained.open regardless' of thg handwheel position. Sinc Waste Water Pump was.in use at the time it was drawing water,e from' the.lA both waste water tank o ., *- -

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'Contrafy to the LACBWR Technical Specif.ications, the c'ontents of .

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the 4500 GWT were not sampled and analyzed prior to release. The *

contents of the 4500 GWT were not batch-sampled prior to releas '

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However, the liquid waste was monitored during the r'elease, and .

since the indicated activity did not exceed thTe. alarm setpoint, the licensee conci'uded that the ac*.tivity of the water' was within ,

allowable limits. Additionally:, the licens&e sampled the contents of the 4500 GWT following this incident ~, and determined that.the '

contents were releasable at'the, dilution rate used. Drain system

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water had entered the 4500 GWT prior to the sample, but.since it was from the sarre sources as would have been present in the tank ~

during the rglease, the sample can be considered representativ Approximately 500 galldns are estimathd to have been discharged .

from the 4500 GW . ,

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This event was due t,o a failed valve whose,c,om' pressor set pin had sheared such that the compressor had separated from the diaphragi The failed valve, a 2-inch Dow lined diaphragm valve, was repaired .

and returned to service. Since this event.was due to an undetected'

failure, the actions taken by the licensee warrant the cl'osing of

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this specific even (Closed)'LER86-06: Reactor Scram Due to Reserve Feed Breaker With Failure of Control Rod 20 to Fully. Insert. On March 7, 1986, during the plant's refueling' shutdown from 72% power, the, operator attempted to transfer the station load,from the main feed to the

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reserve feed. The transfer is accomplished,by t~urning the control switches for the 2400V reserve feed breakers 1A and 1B to clos *

Aftersaid.breakersclosethemainfeedbreakeifortherespecti7e .

bus 'should trip open. When the operator turned the-coiitrol switch for the 1B 2400V Reserve Feed Breaker to close, the breaker failed *

to close, but' the IB 2400V Main Feed Breakgr tripped, *resulting in ,

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loss of power to t,he IB buses..,. . , , .

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- Low voltage on one.2400V bus causes a reactor partial s~ cram which  ;^

fully inserts the center 13 control rods resulting in a reactor- .

shutdown. Subsequent system. interactions generated a fyll scram

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signal c.ausing the r.emajning rods, except for Control Rod No. 30,-

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to fully-insert? *

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The operatory attempted to clo'se the IB Reserve' Feed Breaker, but . , " -

since they were unable to do so, the. 18.2400y feed breaker to the - .

IB 480V bus wa.s subsequently opehed and the 480V b,us tie closed and

. the iB Emergency Diesel Generator was removed from servtje.. On March 8, a spare breaker was installed in place of the 13 Reserve.f. .

Feed Breaker and-the 1B 2400V Bus wa' s reenergize '

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During tire, scram,4Contiol Rod No.' 20 insert to approxi.mately 59

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inches.'(about 30% inserted) and then stopp All.other centrol rods fully inserted and shutd~wn o the reactor. The reactor is

• . required to have a minimum shutdown margin of .5% delta k/k, in the cold clean condition, with,the most reactive rod stuck full ou ,

Since thig event occurfed at the erid of core life, the shutdown margin was considerable more,than the minimum required. Attempt .

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to insert the control rod manua'lly using the electric motor,were

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unsuccess fu,1 ~. ,

Troubleshooting' determined that the hydraulic motor!s. output shaft c.- *

was jangned and not repairable at the site. The hydraulic motor was tak*en to a. manufacturer's'atthorized service representative, where

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it was disassembled. The hydraulic motor was then sent.to the .

manufacturer for inspection to try to determine the 'cAuse of failure. The manufact.urer,j determined that a foreign loose part h~ad been inside the unit from ,its original assembly. The loose par *t

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remained undetected during the manufacturer's performance test and

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through many hours of service; however, eventually the fragment

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shifted into a pas.ition, which caused the catastrophic failur The hydraulic motor was installed'on November 29, 1983 and had experienced appr1ximately 19 scrams,, including testing. It was the

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only motor on the or, der on which it was purchase * Troubleshooting on the 1B Reserve Feed' Breaker include 3 the adjustment _of the main contacts on Phases A and B to increase

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. contact penetration. In addition, the tri breaker adjustments were made to obtaid va'p lueslatchas close was replaced to the and -

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specified values, as possible. Subsequent to these actio'ns, the breaker was tested successfully 35 times in the sho .

'The inspector reviewed the actions taken by the licensee for this event and has determined that the corrective actions taken for

' , the breaker were acceptable and that no . generic implications were .. .

involved in the hydraulic mo1'or failure. The event, therefore, is

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. (0 pert) LER 86-Of: Unla.tched Control Rod. .Thjs event has

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previously ' identified as an open item.in Inspection. Report (eeri . No. 50-409/86002-01, which described the event af follows. On ~

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', March 15, while control god. handling was in progress, the' control

. ' rod in position 19 appeared not to'be.lat.ched to its drive mechanis '

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Therefore, it;was coriservat<ively assumed that tlie rod had been unlatched'si.n'ce September 1984 when .its uppe.r control rosi drive "

, . mechanism was last installe pon discovering the unlatched rod, .

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it was decided to pull test the ro'ds to verify th'at all were -

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latched. Except for two' rods ,that.were not readily accessi*ble, all

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the control rods were pull tested and f6tind to be latghed. In lieu of a pu S tes't, the Wo remaining'contral rods were determined t'o be ,

. lati:hed by usinga go-no go measurements?

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. This event.was highlighted.because of the concerns regarding the

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, ability of an unl'atched rod -to scram as well as' the . nuclear- effect .

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,, of an unlatched rod not beiog in it's programmed position during

. m power operation. These concerns have been alleviated by'the results *

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of. visual ekaminations of Co.ntrol Rod No. 19 ami r'od following checks conducted during reactor startup. For example; T visual ~.

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. . . inspection of Centrol Rod Nos ~19 rev.ealed clean surfeces on the' -

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Y " - lower taper'of the end stud. The'se clean' surfaces suggest that ..

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• . although the control rqd'.had not been latched to its upper control rod drive mechanism, the latch balls were in coritact with th c

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. . control rod's end stud. The Wea,r pattern further suggests that_the

- ~ upper cqntrol drive mechanism's push rod pushed the control rod up (inserted)duringthepastscrams. In addition the clearance check .

• 'for the unlatched contro.1 rod i.pdicated that it%, ould have followed

,- the push rod whenever it was withdrawn. Furthereas part;of.each'

r.eactor startup, a rod following check is co'nducted after ,.-

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criticality is aqhieved (i.e., each control rod is inserted until a ~

definite decrease in power level a'nd a negative period is' observed,

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and then the rod i*s withdrawn trits former position and an increase -

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conducted o January 28, 198 ~q most recent such rod following check was

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. .' Based on.the above., it i's reasonable to assume that Control Rod -

No.19 has. been following its drive, at.least at' the cr.itical .

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heights as determined during the rod following check "

Upon reviewing the event, it was determined that the proced'ure.,for .

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" latching control rods needed imp'rdvement and the tolerance spec,1fied on the data sheet was too great. " Acqordingly, this event was' held , .

as an open. item (50/409-86002-01), pending the revision of the *

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. latching procedure and as'sociated d,ata shee , ..

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Although the tolerance specified in the da.ta sheet has been' reduced,

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the procedure has not as ydt been re' vised nor have the operatprs

, been trained to ' ensure that this event wi-11 net recur.' Therefore', _

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.this event is bein'g held as an open item in this report and to , i *

eliminate dup 1(cation, it is,being admin.istrati9ely d.eleted fPoin

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',, Inspection Re, port No. 50-409/86002-0 '

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- (0 pen) LER'86-08: Auto Start of Emergency Dissel Gens ~rators and .

.- Co inment Js.olation. On' April.3, 1986, during the 1986 refueling .

outa , troubleshooting .was"being performed on an instrument atid 1 . *

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., control problem in the sea) inject system. The technic ~ian started

- < m to lift a lead, which he thought would unparallel two instrument * *

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power supplies, instead, a . low react 6r water level alarm- ., y .-

annunciated, both emdrgency diesel generators started 'and'

,, ~ ' containment.be!1 ding isolation' valves closed. Because of plant *

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conditions (refueling mo8e) the.High. Pressure Core Spray pump .

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, and Low Pressure Core Spray Valve were in " PULLOUT" at the time;

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.therefore..no water was injected into the reacto * *

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, The technician stopped emoving the lead. The emergency diesel

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generatorsgere secured and isolation valves reopened, as desire ...

The dieselattrorting plugs were removet! to prevent * the emergency ' -

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diesel generators froin starting on a low water level signal and r

the lead was again lifted. A low water level signal initiated and .

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isolation valves c'losed. ~An investigation determined that the lead wh.ich was being liftbd supplired power to the three distribution

, panels fed by the power supplies. Reactor Water Level Safety '

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Chagnel No. 1 is suppli.ed by 'one of the distribution panels. As *

the lead was lifted, the distribution panel was de-energized and'

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Reactor Water Level Safety Channe,1 No. 1 failed'down, scal ,

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The cause.of the event.was a personngl error and disagreement

., between the actual wiring'and. the wiring diagran'i print. Since the

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drawing has not as yet been revised, this event is .being held ope <

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' (Clos'ed) LER 86'-09: Retention Tank Pump Discharge Valve Type C Test Failure. Based on an evaluation of the valves performance in'.

, recent years, the licenspe had planned to replace the subject valve

, during.}he 1986 re. fueling outage. Although there was, no regulatory

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requirement to.do so, the licensee decided to leak test the ol .

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valy,e prior to installing the new valve. The test. revealed leakagg '

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thr5 ugh the valve in excess of"48 SCFH, (the top end of8the a

rotameter scale), whereas the LACBWR Technical Specification. limits

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, the combined leakage during Type B and C tests to less than 30 SCF Since the plant was in a refueling outage, containment integrity was *

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- not required at the time of the tes .

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The new valve, a General Valve * Twin-Sea'l. Valve, Model 2C811, was

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' installed on April 4 1986 and passed the post-installation Type C

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test with no leakage, detected through the 'valv' .

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In ligh,t of the above, this event is considered

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- .(Closed) LER 86-10: Containment' Ventilation Isolation due t Instrument Malfunction. On ~ April 4,1986, the* indication on the Oh'

' containment building gas' activity monitor and air ejector offgas a

monjtor failed high. The containment buil' ding ventilation dampers 4

, and vent header valve closed automatically en the high containmen *

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building gas activity sigrjal. The indications on the contairment *

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building particulate. geti,vity-and radiation. monitors were normal The plant was in a. refueling outage, so no offgas was being .

l generated. The control room instrumentation f,or the containm.ent

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' * bui'1 ding gas activity monitor and air ejector.offcjas monitor share ' '

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a c.ommon drawer, therefore,.the problem ~was thought to be with the ., , instru' ment drawe . .

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..' The fuses 'were checked and none was found blown. After: wards, the

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, drawer was pulled.out and pushed back and the indications returned to normal. Troubleshooting performed on the drawer deisected no problem ,,

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' that cou'l.d have. resulted in the observed malfunctio .e

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Sincd the pjant was in a ref'ueling outage, containment integrity was #

, , . not required and the safety signif.icant.of this incident was lo . .

, Based on the troubleshooting performed by the licensee and the

'results thereof, the inspector believes that the event was of. a

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spurious origin, and that it sho'uld be considered close ' -

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. (0 pen) LER 86-11:, High Pressure Core. Spray Bundle. 0.n April 3,

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1986, follqwing the completion of.refueTing operation, the High Pressure Core Spray (HPCS) tube bundle was being installed in the

.' react 6r wissel. While the bundle was being. lowered into the reactor ,

. vesse1, it contacted the top of the stearn dryers or other adjacent o -

vessel internals at least twice. On April 4, when the workers went

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to bolt down the bundle, they found that the bundle was sitting .

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. , approximately 1/2 inch higher than it should be, and attempts.to -

seat the bundle were unsuccessful. The bundle was returned to th>.

fuel element storage well and inspected. The four outer most tubes ,

were observed to be bent inward., The north ~ west tube was bent-aboot .

20 degrees, the northeast about 30 degrees and the southwest and -

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southeast tubes about 5 degrees from the vertical. The northwest .

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and northea'st tubes were bent to.the extent that they..would not have

. been able to provide adequate core cooling if the bundle had been

., installed and emergency. core. cooling need ,

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The four tubes wereestraightened and a subsequent analysis indica'ted that the tubes were not excessively sti*ained when straightened. An air tsst was performed which showed the flow .

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through these four tubes to be norma ,

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A special safety. inspection of this. event was conducted by,

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Region iII based inspectors. The results of the inspection and evalua. tion of the analysis are documented in Inspection Report

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No. 50-409/86005(DRS). The report reads, in part, as follows: ,

" Based upon the r.eview of the engineering evaluation, the inspectors l have no further concerns ie ttiis area". Based oh.the findings,

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.this event'wbuld n'ormally be closed. liowever the licensee has .

• O identified uncle ~ar markings for, the lining up,of the crane ~as a

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contributor to this event and-had stated that the marking will be ,.

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improved? This event, therefore, is being held open pending the'

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, licensee ~ 's, improvement of the markings for aligning,the. cran .

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. (0p'en) LER 86-12: Monitored Discharge of Unsample Waste Water with

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Anal zed Waste Water. On April 9, 1986, the.4500 llon Waste Ta'nk ,

(GWT in the.. turbine b'uilding was-being discharged to'the river.- -

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The*discha'rge commenced at 0445, and at 0938, the auxiliary' operator

. . . noticed that although over~3000 gallons ha' dbeen pumped from the

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, , tank, the level was at.535. He secured pumping the tank,'and it was

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later determined that approximately.875' gallons had overflowed fro .- the 3000~GWT into the 4500 GWT. At the time'the discharge of the .

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4500 GWT began, the 3000 GWT was filling yp. The turbine buididing '

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i sump pumps were pumping into th'e,3000 GWT, until they were secured *

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e at approximately 0600 following . receipt of a high, waste water tank

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level alarm. The washing maching.was also discharging into the 3000 GWT. These water streams caused the 3000 GWT to overflow to the

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4500 GWT. The water was mainly ground water which was seeping into

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the turbine building tunnel due to high Mississippi River. water'

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-- 3 - - . Contrary to the LACBWR Technical Specifications the liquid waste ,

contents itom the 3000 GWT.had not been batch-sampled and analyzed, prior to release. Th'e 4500 GWT had been batch sampled and

. isotopically analyzed. The results indicated the' tank activity was the equivalent of 3.38 MPC-W (Maximum ~ Permissible Concentration in

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Water). With the dilution. flow rate taken into account there would ,

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have been 5.09 E-4 MPC-W at the discharge point. There were 3125

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' gallons of water discharged. Although the contents of the 3000 GWT

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had not been sampl.e.d prior to release,. the liquid wastes.were

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monitored.during the release. Since.the . indicated activity did not exceed the alarm.setpoint, the activity of the water.was within allowable limits. Additionally, the contents of the 3000 GWT were

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sampled following this incident and determined to be releasable at -

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the dilution rate used. The 300.0 GWT sample results indicated that the tank activity was the equivalent of 4.14 MPC-W. Since

, .approximately 875 gallons of the total 3125 gallons dis. charged were

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from this tank, the actual tank' water equivalent MPC value during .

discharge'was 3.59. There would have'been 5.4.1 E-4 MPC-W at the - ,

, discharge point. Therefore, the liwits specified by Technical Specification 4.3*.1.2 were not exceeded, nor were the dose commitment limits specified by Technical Specification 4.3. .

Corrective-actions taken by the licensee included operations-personnel being reminded of the need to maintain ~close control over the . waste gater tanks' inventory while high river water leve.1 is contributing to faster than normal water accumulatio ~

This is the first eyelit report due! to this. specific cause; however,

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similar occurrences were discussed in LERs 79-05, 85-06, and 86-04,-

but th,e circumstances differed.' In' addition, a similar occu~rrence '

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is described in LER'86-14, both of whieh are being held open pending the licensee's decision on further~ corrective. actions such as plant mod'ification to help prevent further incidents of this nature.,

~ LER 86-13: Auto Start of IB Emerggncy' Diesel Generator-M(Closed)'s Err'oneou Undervoltage Signal During Testings On April 18, 1986, the refueling shutdown test of the 2400 V'olt Bus 1A and 1B-

. . . Undervoltage Relays was.being conducted. During this test the " =-

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Emergency Diesel Generators (EDG) supply the 480 Volt Essen.tial Buses. At the end of the test, the EDG's are removed from service by tripping the diesel generator output brealeers, which causes the 480V' Esserftial Buses MainJeed Breakers to close, shutting down. th,e '

diesels, and then returning the EDG control switches to auto. When the IB EDG control switch was returned to auto, the IB 480V

. Essential Bus Main Feed Breaker. tripped, the IB EDG started and'it's'

output breaker closed to supply the bus. This sequence was repeated .

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. several times during troubleshooting with- the same result ,

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Troubleshooting revealed a blown fuse'on the IB 480V Essent.ial Bus .

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metering potential transformer, ciusing a false undervoltag'e signal 6 to' exist on the 18. 480V Essentiarl Bus. Thus, when the 1B EDG

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control switch was returned to auto, the false undervoltage signal -

caused the IB EDG to start and its output breaker to close to supply the bus. The blown fuse was replaced after which the systerp functioned properly. This event has been attributed to a random

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failure of a fuse and is considered closed.- . (0pe'n) LER 86-14: Monitored Discharge of Unsampled Waste Water with -

Analyzed Waste Water. On April 18, 1986, the 3000 Gallon Waste Tank ' .

IGWT) in the turbine building was being drischarged to the rive . x Appro'imately 81/2 hours after, the -discharge commenced, the roving *

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auxiliary operator no.ticed that the flow totalizer read 4100 gallons. .He checked the waste water tamks and.found the suction .

valve from the 4500 GWT to the o'perating waste water transfer pump op.en. He shut.the valve and also secured the discharge from the *

3000 GWT. It was determined that approximately 2445 gallens from the 4500 GWT had been discharged. The main sources of water in the

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saste water tanks were the washing machine ind ground water which was seeping into the turbine building tunnel due to high Mississippi River water level. Contrary to .LACBWR Technical SpecMications, the contents of the 4500 GWT had not-been' batch-sampled and analyzed prior to release. However, the liquid waste was monitored during *

the release, and since the indicated activity did not exceed the

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alarm setpoint, the activity of the water was within allowable ,

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limits. Additionally, the contents of the tank were sampled' an *

analyzed following this incident'and , determined to be releaseable l at the dilution rate use ,

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The 3000 GWT, which was sampled, had an activity concentration of 2.72 E-4 uCi/ml or~the equivalent of 8.09 MPC-W (Maximum Permissible Concentration in Water for 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> / week) and with dilution was

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t.,12 E-3 MPC-W at 'the point of discharge. The 4500 GWT, which was

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sampled post-disc.harge, had an activity concentration of 3.15 E-4 .

uCi/ml'or the e i l

' concentration 'w'qu va ent o,f 9.02 MPC-W. -The calculated effective as-2.94-E-4 uCi/ml or the equivalent of 8.62 MPC-W in

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the tanks and an effective discharge MPC-W.of 1.19 E-3. Therefore, *

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the limits of Technical Specifications 4.3.1.2 were not exceede ,

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1.ikewise, the dos.e to the. public was significantly below the limits '

. of TO CFR 50 Appendix ,3 ,

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As a corrective measure, the plant superintendent talked to each

... shift supervisor and emphasized the importance of careful waste water handlin ~

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In addition, major 'modificatiops were made t'o the waste water h.andling procedures. Prior to the procedure changes, either.one i of two pumps could be used to pump either. tank. It was decided to-l dedicate a specific pump to a specific tank. Valves connecting -

each pump to its non-dedicated tank have been locked clos'ed, with o: unique locks. The tanks and pumps will only be allowed to be cross-

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connected during special circumstances with additional procedural control. The requjrements to specify which pump discharge valve;-

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, ' is used -is beitig added to the tank discharge shee * '

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Add'itionally, plant modi.fications are being.cohsidered to further help prevent any future incidertts of this nature. *

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This is the third time this year that unsampled waste wa.ter has '

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been discharged with analyzed waste water'. The first event (see writeup on LER 86-04, this repgrt) was attributed to a random

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undetectable failure of a valve and not to operator error or '

, negligence. Accordingly, based on the circumstances of the event .

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and the corrective actions taken by the lisensee, said event was

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closed. In contrast, the last two events (LER 86-12 and this LER),

were both due to either operator error or operator negligenc '-

Some corrective actions have been taken by the licensee to preclude recurrence of such events (e.g., procedures have been modifi.ed and

. shift supervisors.havs been counseled. Nevertheless, because of ,

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the recurring nature'of this type of event, this LER and LER 86-12 are both being held open pen' ding further training of' licensed . . . ,

' operators by the licensee and the implementation, if any, of plant

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modifications being considered. -These two ev'ents are still.being '

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reviewed for possible enforcement ac. tio _ , (Closed) LER'B6-15: Reactor Trips due to Nuclear Instrumentation -

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Spikes- During Shutdown. and Startups. On May 6,' 1986, the reactor ,

was taken critical and startup. testing was. initiated following completion of..the 1986 refueling outage. Due to a malfunction on the lower control god. drive mechanism (LCRDM) in position No. 3,

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the reactor was maTuall.y shutdown by inserting all the control rod .

The malfunction did not affect the ability of the mech.anism to drive the control ro . ,

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' While the reactor.was shutdown, a spike occurred on Nuclear

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, . Instrumentation (NI) Channel No'.6 which generated a scram signa).

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The contral rod scram' solenoids de-enerigized an,d;the mechanisms .

discharged..Asstatedabge,allcontrolrodswerefullyinserted e,

. prior to the scram signal, thus, rod m'otion.per se, did not occu ,

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. . NI Channel No. 6 and.NI Channel No. 5 comprise t.he wide rang *e.NI channels and are configu' red in a one-of-two trip logic at low power, ,

Thewideranfe' channels.hagerangeswitcheswhichare*upscaledas

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peger, increases such that a trip is generated if the signal exceeds

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approximately 115 on a 150 scale or 46 on a 60 scale. The NI ,

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channels were .on the 60 E-5% power sca'le at the time of the spik '*

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'The wide range ch.annels are very. sensitive to noise spikes while on .

the lower ranges. A surveillance. test was performed on NI Channel

. No. 6 with no defects-or problems foun ,

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The reactor startup recbmmenced on~May 7, and on May 8, while .

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, performing the startup testing,.NI' Channel No.,5 was downscaled to .

the 150 E 6% scale. .Approximately 1 minute.later, a spike occurred

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• - on NI'Cha,nel n No. 5. Although the meter indication did not exceed, 75% and the recorder showed only 85%, a scram occurred even though .

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the setpoint 'was at approximately 115% on the 150 E-6iscale. All -

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rods fd.lly , inserted and the first out scram alarm was " Reactor All Rod * Scram", rather than " Channel 5 Flux Level Hi". Following the

. si: ram, NI. Chani1el No. 5 becanie. noisier with time and was *

c9ntinuously generating alarms. It wars therefore, concl0ded that a very fast spike on NI, Channel No. 5 had caused'the scram, and it

. was postulated that the all rod scram s circuit operated faster than ,

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%ther circuits. Hence, the first out alarm was " Reactor All Rod

Scram".. The NI Channel No. 5 instrument drawer.was replated 4 th -

the spare. No noise was experienced with the spare in service and a surveillance test was performed with satisfactory results after '

which a reactor startup was commence *

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At approximately 0800 on May 9, some spurious " Flux Level Hi" . alar'm ,

were received on NI Channel No. 5. At 0843, NI Channel No. 5 " Flux

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Level Lo", NI Channel No. 5 " Flux Level,Hi" warning and NI Channel No.5 ". Flux Level Hi" scram al, arms were received. The reactor -

scramed from 25 E-4% power. All rods. fully inserte*d. Following

. the scram, it was noticed that the positive high voltage power 4 supply to NI Channel No. 5 was indicating above 1500 volts, which ,

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is the, top of scale; versus' the normal 610 volts. The NI Channel No. 5 indication was spiking up and down and t.he power supply '

voltage was fluctuating. The high voltage power supply for NI *

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Channel No. 5 was repl. aced, and a siurveillance test-was conducted with sati.sfactory result .

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A filament was found to be burned out in a tube in the po'sitive high e

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voltage power supply. The failed tube was subseque.ntly removed from ,

service. The licensee surmised that as the t'ube degraded, spiking would have occurred and that when the tube failed,'there was no

• < voltagd regulatjon. The licensee further believes that.this was

, a,lso the cause of the scram on May 8. Minor spiking had also been

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experienced after the,startup on May 8. Some connectors were cleaned and this had appeared to hav5 reduced the spiking *. The '

, . gradual degradation of the power supply is now:.-believed responsible

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for the spiking and the tube, failure is thought to be random -in -

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nature. The tubes in the nuclear instrumentation power supplies had

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been checked during the refueling outage ~. Based on the actions ,

taken by the 1.icensee, coupled with the subsequent results, this '

event is considered closed. further, such events should be greatly

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, reduced, if not eliminated, after the nuclear instrumentation system is replaced with a new G. 'E. syste i

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" ~ ' Degraded ~ Fire' Barrier.- On'May 12, 1986, the

. (C1'osed), LER 86-17: -

, plant was starting up following the 1986 refueling outage, th . 18-month fire barrier surveillance was- being. performed. During the, , ,

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course of the. surveil-lance, a small opening,_approximatbly 1 square inch, was-found in a cable tray passive fire barrier between the -

electrical equipment' room and the turbine. building. An' hourly , fire

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watch patrol was established, in accordance with technical ~

specifications, until the barrier was repaired. , ,.

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Apparently, the baTrier had.not been. completely sealed following s maintenan'ce performed during the refueling' outage. Information'

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on the incident was .difseminated to apprdpriate plant personnel, ,

reminding them -to inspect fire barriers following maintenance "

involving suc,h barriers and to repair the barriers, if,neede * Theactionstakenbythelibenseeforthiseve'ntareconsibred

. acceptable and suf.ficient, therefore, this event is considered .

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close ~ Plant Trips and Force *d Manual Shutdowns ,

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At 1841 on May 6, 1986, at the c6mpletion o*f the' extended reYueling

. l outage which commenced on March 7,1986, the reactor was taken critical. -

and startup testing was commenced. Criticality was atta'ined with th nine controlling rods (i.e., the center rod and rods in positions 6 thru 13) withdrawn 11.5 inches and the remaining twenty rods < withdrawn 13 inches. These positions compare favorably with the estimated critical positi6n of 11 inches for the controlling. rods and 12.5 inches for the-remaining rods. Subsequent to having been taken critical, the plant experienced the following forced manual shutdowns and trips:

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a .e At 2015 on May 6','the reactor'was manually shutdown due to a -

malfunction on the lower' control rod drive mechanism in posit' ion No. 3. At 1822, on May 7, the reactor w'as taken critica . At 0028 on May 8, the reactor scrammed from low power.due to a spike on NI Channel No.'5. The instrument drawer was replaced an,d

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the reactor was taken critical ,at 0652 on May ,

- * At 0843 on May 9, the reactor scrammed from low p.ower due to a .

, spike on NI Channel No. 5. The spiking was determined to be due to

degradation and subsequent' failure of a tube'-in the positive high .

voltage * power suppl '

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. Thb p'ower supply was repl' aced and at 1520

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on May 9, the reacto' r was again tak'en critica *

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d. . At 0231 on May'10, the reactor was manually shutdown from low power ,

because of a* fire on the lagging around the IB Forced Circulation - ,

Pump. The' fire was ' extinguished in about nine minutes aqd at 2001, ,

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after the insulation had been replaced, the reactor was again taken

critica ,

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~ At 0702 on May 13, the reactor scrammed from low power due to the ,

failure of the 1A Static Inverter. A circuif board in'the inverter was ' replaced and the reactor was taken criti. cal at 2001 on May 1 At 1202 on May 15, the reactor-was manually shutdown from low power ,

, - becaus6 of water leaking- from. e upper flange of Upper C'ontrol Ro'd -

Drive Mechanism No. 2. The flange' bolts were tightened and th leakage stopped. ' At 1512 on May 15, the reactor _was taken critical '

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,and the turbine-generator was synchronized with_the grid at 0607 on .

• . May 16, ending the 1986 refueling outag .

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. At approximately 1220 on May .25, the 1A Fo'rc6d Circulation Pump  %-

(FCP) tripped due to the loss of seal inject flow.' Reacior power -

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decreased from about 78% to 47%. This event was due to water in the

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controlley's regulator which, in turn, caused the supply valve to-

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the 1A FCP to 'close thereby stopping seal inject flow to the pum .

Since the regulator for the IB FCP was behaving erratically, the reactor was mdnually shutdown at 2045 on May'25. During the .

. shutdown, water was drained from the control hir system, especially .

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that portion of the system assoc'iated with, valve regulators for the "

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seal' inject system, after.which the regulators were steady. At 0020

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on May 27, the reactor was again taken critical and at 1533 t, . tur,bine generator was synchroni' zed with the gri .

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, . Subsequent to the las't mentioned outage, the plant was placed on a slow '

power escalation and is presently operating at 99% full p6we '

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Following the plant shutdown on May 6, and the reactor'. scram on May 8,

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'"- the inspector ascertained the status of the reactor and saf5ty systems '

by observation of control ' room indicators and discussions with licensee

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personnel concerning plant parameters, e'mergency system status and reactor coolant chemistry. The inspector verified the establishment of proper communications and reviewed the corrective actions taken by the licensee.- .- .

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• Based on the rev.iew of information provided by the lice'nsee, all systems-responded as expected, and the plant was taken critical or returned to '

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power operation subsequent to each listed scram or manual shutdow '

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' Startup Te_ sting - Refueling '

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The inspector observed the startup test on Maj 6, and verifi.ed, that

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refueling outage startup testing was conducted in accordance with -

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~ technically adequat,e procedures and that the facility was bjiing opdrated .

within license -liinit ,

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- Open Items , .

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, , Open items are matters which have been discussed with the icensee,'wliich l will be reviewed further by the inspect *or, and which involve some-action

,- on the part'of the NRC or licensee or both. New open. items are described l iri Paragraph ,

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The inspector met with licerise.e representatives (denoted in Paragraph 1) ~ -

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throughout the month and at the conclus9on of the inspection and * - -

sumarized the scope and f'indings of the inspection activities. The

.,. licensee ccknowledged the findi'ngs as r.eported herein and did not

^ ideq$1(y such documents or precesses.as proprietar ,

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