ML19319E259

Plant Operations Rept 1977

ML19319E259
Person / Time
Site:	Rancho Seco
Issue date:	12/31/1977
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML19319E257	List: ML19319E256 ML19319E259
References
NUDOCS 8004010533
Download: ML19319E259 (13)

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PLANT OPERATIONS REPORT - 1977 i-l RANCHO SEco NUCLEAR GENERATING STATION UNIT No. 1-1:

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OPERATING LICENSE DPR-54 DOCKET No.-50-312-t 4

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-TABLE-0F CONTENTS--

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a Sunnary/of Reactor' Operations l I

Changes,- Tests or Experiments Subject to

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210CFR50.59(b)'

7-Major [i.tems..of' Sa fety _ Related? Mai ntenance 10-

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Narrative Summary of Reactor Operations January;1 lThe re' actor was operating at '100% ) power at 'the start of the

-new year.

7 The t'rlp of a' main.feedwater pump at 0937 resulted in a runback 2 in reactor power to 60%.. At 0950 a power increase was started

and a two-hour hold was started at 1050. At 1310,-the power was' increased.to 100%.

13-Power'was dropped lto about 86% for testing of' the turbine

' throttle-stop valves. The reactor returned to 100% power at 0923 Losst of both-x.aln feedwater pumps on thrust bearing wear trips l(spurious) :resulted in a reactor trip at 1554. The reactor was

~taken critical at 1812.

l14' The turbine was~ rolled with steam at 0342, and the unit paralleled to the grid at 0504.

Reactor power reached 75% at 0711.

Reactor power was in the 87.5 - 92% band at 0930, starting the two-hour hold. The reactor, was taken - to 100% at 1130.

February 5 A main feedwater pump tripped, and the reactor was run back to 60%.

Reactor power reached the two-hour hold point at 1135, and 100% at 1700.

17_

At 1228 a main feedwater pump tripped and the reactor was run back to 55%.

The return to full power began at 1315 and the two hour hold started at 1444.

Power reached 100% at 1717 25 Because of low oil level in the C reactor coolant pump, a

power reduction was started at 2306 to secure the pump.

26 -

The unit was taken off the line and power dropped to hot standby-at 0248 to allow filling the oil reservoir.

The turbine was latched lat 0620 and following sone testing the unit was paralleled at 1118.

At.1915 the two hour hold was begun at a power ' level-of 91%.

~27~

' Reactor power _ reached 100% at 0002. The reactor was run back to 60% at 0630 due to a trip of a main feedwater pump.

i Reactor _ power was_ returned to 92% at- 0728 - for the two hour 1 hold. -Power was increased to 100% at 0958.

March 4

A main. feedwater _ pump t rip ' caused reactor _ power to run back to 60% at '0019. ~ The two. hour hold was started at 0055, and L

.100%-power. reached at'0322.

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o March' I. 7A't 31059' the reactor poaer sthrted' to decrease following

.(Continued)~ 'overboration of'.the RCS ~ caused by. failure of the feed and l bleed controller.

By 1359 the two hour hold point at 92%

was:; reached again, and by 1706 power was increased to -100%.

A~ runback in react'or power to 58% was caused by the trip of 10 a' main feedwa ter. pump at 2313 Reactor power-reached 92%

lat. 2343, beginning a - two hour hold.

11 Reactor power was raised to 100% at 0340.

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At 2211 the turbine was tripped in accordance with startup test procedure 800-14.

The reactor was taken to a hot.

standb~ condition.

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'The mai.n. turbine was rolled with steam at 0310, and the unit paralleled at10338.

Reactor power reached 87% at 0913, where a two hour hold was initiated.

At 1212 reactor power reached 100%.

18 A reactor runback to 60% occurred at 0932 following an assymetric rod alarm.

Rod '4 of Group 7 dropped into the co re.

The rod was relatched and withdrawn, and power was increased to 92% at 1210 for a two hour hold.

Reactor power

- was raised to ' 100% at 1505 23 At 1420 the reactor was run back to 60% due to feedwater block valve failure.

Reactor power was returned to 92%

at -1445 for a two hour hold, and reached 100% at 1756 25 Power was reduced at 0730 to permit inspection of one condenser for a leaking ' tube. At 49% power, two of the Circulating Water Pumps were stopped and the leaking tube was located.

Reactor power was raised to'91.5% at 2315-for a two hour hold.

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.Rea" ir power reached 100% at 0250.

~29

' At _0837 an evacuation drill with a simulated fire in-the Auxiliary _ Building _was. initiated.

At.0917 the drill was terminated.

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J31; L A ' main feedwater pump tripped at 0325. and.the reactor ran :

Lback toJ70% power.

At '0720 'the plant wast at 90.5% for a

'two hour-hold, and at 0950 power reached 100%.

April. Li3f

At 1053 a ' main _ fee'dwater pump tripped and the reactor was

,run'back'to 80% power. :By'1109_ power reached 92% for a 4two hour hold,,and it reached 100%'at 1319 w

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April

'.14

.Due'to an oil leek on a main feedwater -pump, power was

~ reduced to 80% at-1747. At 2152 power-was raised to 191 5% for. a two hour; hold'.

151 4 Reactor-power was raised to 100% lat 0120.

'21-Atz 0630 the reactor was run back to 60% power due to an assymetric control rod alarm for Rod 4 Group 7 The rod icould not be relatched, and power was reduced to Ilmit tilt. The unit separated f rom the. grid' at 0953, and reactor

. power was reduced to 2%. At 1130 the reactor was manually shut down..It was determined that the cause of the dropped red was a-failed control -rod drive stator.

22.

The reactor was taken critical at :1110 after replacement of the damaged stator.~ The turbine-was rolled with steam at 1336, and the generator was brought on line at 1614. -At-1843 the reactor power level was 88%, and the two hour hold was initiated.

23 Reactor power was raised to 100% at 0023 May 21 A unit shutdown was initiated at 0200 to permit repair of the Pressurizer Spray control valves.

At 0417 the unit separated from the grid and the reactor was taken to hot

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standby.

22

'At 1624 the reactor was manually tripped.

The reactor was taken critical at 1942.

23-

.At 0046 the turbine'was rolled with steam, and at 0134 the generator was brought on line. The reactor reached 87%' power at 0438 and began a two hour hold.

After bringing the nuclear instrumentation indication within 2% of the heat balance reactor power level, power was raised to

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100% at 2015 June 21 Due to high temperatures in the B Hain Transformer, power-was reduced to 92% at 1702.

Power was returned to 100%

at 2111.

.24 A1 plant evacuation was called when alert alarms on the Auxiliary-Building stack radiation monitors came on.

It was' initially. assumed that the activity levels were coming from-work being 'done on the Reactor Coolant System Drain Tank.

It was later. determined that the increase was due-to

-reactor-coolant sampling in the radiochemistry laboratory.

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Reactor p' wer was1 decreased to 66%.at 0100 for testing of o

'the. turbine.throbble-stop valves.

Th~e return to full power.

-involved 'a two hour. hold' starting at 0203, reaching 100%

at 0459 3

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KJuly 27; 1 A' quarterly - plant evacuation drill - was held, starting. at

0830. The dr.ill was terminated-at-0944.

A reactor trip occurred at 1144. 'With one CRD transforner 29.

t out.of service,. maintenance work on the CRD programmer

.apparently caused a faul t which' dropped a control rod.

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Theireactor was taken critical at 1353 The turbine was rolled-with.s team at 2330, 'and the generator placed on line atL 2356. ; At. 0430 the plant reached 92% power and. started a two_ ho' r. hold. At 1230 the nuclear instrumentation was u

indicating within 2% of the heat balance calculated thermal

- power level,' andia power increase to 100% was started.

August' I

One of: the four Cifculating Water. pumps was taken out 'of service _ due to bearing failure, and power was reduced to 80%-at 0038.

Power-was raised to 85% at 1155 At 1605 reactor power was raised.to 90%.

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2 Reactor power.was increased to 93% at 0900.

5 An upset in the system at 1525 dropped f requency to 59.~4 Hz.

Reactor power was dropped to 79%.

Power was returned to 93% at 1535 This power level was maintained

.(with one Circulating Water Pump out-of-service) for the remainder of the fuel cycle, permitting completion on the

- scheduled date.

11 Poweri o.the letdown valve was~1ost at 1520, and reactor t

power was reduced to 87%.

By 1540 powe to the valve was restored and reactor power was increased to 93%.-

20 At 0015-a norcal shutdown for the first refueling was initiated.

The plant separated from the system at 0253, and the reactor

. was shutdown.at.0522.

The ~ reactor proceeded through a cool-down'an'd reached cold shutdown on August 21.

22

' Start of turbine overhaul.

- September;3 The; reactor vessel head was removed.

- 12 UStartlof fuel movement for refueling.

12 4 Qompletion of fuel movement.

.29'.The rea'ctor vessel head was replaced.

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40ctober' s2

- Start of reactor building integrated leak rate test.

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-_~~'W 0ctober-30 LAt-1011 plant _ heatup was initlated to bring the reactor

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critical: for physics testing.

31l The reactor reached -hot shutdown at 0545 1 November 2-

.The reactor lwas taken critical at 2107, and zero power physics. testing was started.

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. The reactor was manually tripped at 0104 in accordance with

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.the physics test-procedure.

The reactor was taken critical at 0137 At 0920 the reactor' was shutdown in accordance with Technical

-Specifications due to an unidentified RCS leak rate in excess

-o f i l i g pm.

The leak was located and corrected, and. the reactor was returned to critical at 2351, resuming the physics testing.

5 At 1413 reactor power was -increased, initiating a process of resetting' the gain of the nuclear instrumentation to obtain prope r. indica tion.

The gain settings were altered during physics; testing to provide trip protection at a low power level. 'At-1825 that last adjustment was made, and the indicated and actual reactor power levels were 5%.

Power-was then. increased to 15%, the turbine was latched, and turbine testing was started.

' 6' z Theigenerator was paralleled to the grid at 0131.

Power reached 40% at 0330.

At 1300 power was decreased to 15%,

-and at 1335 the unit separated from the -system for turbine overspeed trlp testing. The turbine was latched at 1609, and tha: plant brought on line at 1632.

Reactor power was increas'ed to 40%.

Power escalation testing was performed at this plateau.

8 At 2232,' Rod -2 from Group 2 was manually dropped in accordance with the physics test. ~The power level of 40% was maintained.

.9 The dropped rod was withdrawn and returned to the group at 0423. At 0925 a power increase to - the 75% plateau was

- s ta rted..The high flux trip setpoint was raised ' to 85%

power.

The reactor. reached 75% power at 1832.

11 Reactor power was reduced to 15% starting at 0800 for repai r. of ' a' rehea te r.

Power. returned to 75% at 1415 A

power increase - to 100% was 'then initiated upon completion of.

the 75t' plateau. testing.

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At:0400 the reactor was at 92% power, starting a five hour hold.

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Noveeber>12: fPowerfwaslincreased.tof95% at: 1151, and then to 98% at

~(Continued) 1451 3JPower reached-100%!at'1656.

117f ?A' manual (plant shutdown was started at 1300 in response to.

, an' unidenti fied RCS leak rate in Lexcess of 1 gpm.

The e plant' was taken off line at 1506,' and the reactor was shut

?down at 1617 A valve was backseated 'in.the containnent building, stopping a' packing' leak.. This action reduced the RCS 1eakage below 1 gpm, and the ' plant' was taken critical

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'at11830; The. turbine was rolled at 1920 and the generator.

ibrought' on 1ine ' atL 2000. '

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-Power reached 98%.a't 0030,1and a two hour hold was started.

19, LThe~ nuclear? instrumentation Jindication was within 2% of

'the heat balance calculated power level, so power could be Increased to1100%~ at 0103

-205 :The; physics testing program required an APSR scan to be perforced at 'the 75% powe-level, -so power was reduced at 0000.

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.21 The 75% power level testing:was completed at 1811, and power was increased to 92% for the two hour hold.

-22'

'The reactor reached 100% power at 0132.

- Dececher.3' A leakIfrom theihigh pressure turbine required taking the plant off. line for : repai rs.

The power r' eduction started at-0600 and the generator separated from the grid at 0655

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-The ' reactor was-kept at 15% power. during the outage.

The-turbine wasirolled at.1643 and the unit brought on E.

line at.1900.

, 41 J The. power increase.was : stopped at 00541with the reactor a't 87% for a test of the turbine governor valve.

One governor.

would.not operate. properly, limiting operation at 85% power.

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Between =1200 and 1500 several 'powerilevel changes were made In, an attempt :to':open the governor valve. -The valve did open,.and the unit was. operated at 90% for a ' two hour hold.

! Power reached 100%-at11904.

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cThe plant operated Lat 100% the rest, of the month.

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to 10 CFR.50.59(b);

Changes / Tests or Experiments Subject Duri n'g ! 1977,'the?following' changes',' tests and experiments were completed which constituted ~ changes in Safety-Analysis Report descriptions but which did not Involve Technical' Specification changes or unreviewed safety' questions:

1.)' The-management review of' Revision 6 to the Rancho'Seco Emergency Plan was 18, 1977..With one' exception, the changes made to completed o'n February.

the Plan: Involved editorial corrections, clarifications, or minor

' expansions.of individual responsibilities. The one major change involved raising the' action level for population evacuation (based on estimated thyroid dose 1 calculations) from f.5 to 7.5 rem. When the Plan was initially

.wrl.tten,~no criteria were available for thyroid dose limits so the 1.5 rem limit was chosen as'a very conservative value. This number has proven

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Impractical for a variety;of reasons, including the inaccuracy of measure-ment' of.the: low' radiat on levels involved. The 7.5 rem' limit is still near i

the' bottom range of values that have recently been recommended by the EPA, i;

there fore : the improved accuracy of measurement and the increased time period available for evaluation of offsite radiation data can be obtained without increasing the danger to the general public significantly.

2.)' 1The review process for the Emergency Plan, Revision 7 was completed on

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.0ctober 27; 1977 The major portion of the revision consisted of editorial changes and clarifications. The few changes of significance covered the -

following:

dropping of ERDA as an offsite response agency for sabotage incidents unless nuclear weapons are involved; converting the Plan to show

~ he coordination function of the couaty emergency organization, previously t

performed ~ by the state; addition of bloassay requirements; and revising the first-aid training program from.one year retraining to three years in conformance with the American Red Cross guidelines. These changes were-made.to increase the effectiveness of the Plan, and did not increase the

-hazard to the public..

3.)f The safetyEfeatures actuation of -the isolation valve on the reactor coolant pump seal' injection line was modified to delay closure of the valve e

until all four reactor coolant pumps are' secured.

Seal injection flow is

'provided. from the high pressure injection pumps, and the reactor vendor has immediate 'i: olation of this line is not necessary. This change ve ri fied - that s

was made' to insure that seal' water is available until the pump is stopped, preventing damage to the' seals and the potential for loss of large quantities of coolant; through destruction of. the seals. The seal injection line remains za high pressure injection source until the pumps are secure, at which time the d

Isolation valve automatically closes. No ' change in the amount of high

. press'uresinjection flow provided results ' from this modi fication. The manage-ment review for the' change was completed March 22, 1977 (Diawing Change Notice A-1240).

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.The FSAR' description' of_ the s'tartup accident from zero power was. found to

containL some inaccurate assumptions. The maximum worth of a fsingle control rod ' group was ; listed Eas 2.25% 6k/k with a maximum reactivity insertion rate

.of 4.5x10-4 Ak/k/2WD. These values were based on the original design -

. 'where ~ alli control rod - groups were moved independently except <for~ 25% overlap

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at the ~ ends fof their= travel. ' A design ' change combined ' group. 6 'and -group 7 '

, :(regulating) 3into' a-single group; which resulted.in a total group worth of -

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13.26%?Ak/k withia reactivity insertion rate' of 6.20x10 Ak/</%WD.

1The. safetyLanalysislof this discrepancy showed that although. the parameters-

- had changed, sthed reactor was still adequately protected, receiving a. trip sig'nal;on,highl neutron flux with thermal power at 43% FP.

The original analysis. resulted in a trip'on high reactor coolant pressure at a thermal

power of 77% FP; therefore, the transient' induced by withdrawal of group 6/7 5

Kis no l worse than-the' analyzed case presented in the original safety analysis. The non-conformance ^was accepted, management review being

compieted on-June 24,.1977 (Nonconforming Report S-631).

$);OnAugust-12, 1977; a modi'fication to the makeup system was completed

_ which provided a flow path from the makeup pur ' discharge to the pressurizer.

f This change insures that a flow path'through a core is maintained during the.long term cooling period following a LOCA. This. change was made-in

. accordance with NRC requirements to prevent boron precipitation during this

cooling phase. The 1Ine wi1i provide the 40 gpm that Babcock and Wiicox has determined necessary-to prevent precipitation.

(Drawing Change Notice

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6. ). Mofifications to the plant perimeter security installation were made to reduce several operational problems while enhancing security of the site.

The management review of this modi fication was completed on August.23,1977..

H The original system will rer:,in in operation until the revised system 'is -

approved as part of the new security plan.

(Drawing Change Notice A-1495.)

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7.)- The switchyard breaker configuration was changed to move the Bellota #2 line from its existing position to what was originally the " Future" position.

This modification was made to reduce the possibility of a generator load rejection.if both Bellota 1ines.were lost.

This change improves the-reliability of the ' plant and does not affect nuclear safety.

This' modification was completed August 25, 1977 (Drawing Change Notice

'A-14.40.)

8.) l The diesel ~ generator air start systems are required to have sufficient capacity for five-starts without-recharging. The originally installed

. pressure instrumentation in those systems was not adequate to provide the

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~. con _ trol room proper warning that the air receivers. could no longer. provide the five starts. New-pressure switches were added so there now is an alarm ;when there is only. adequate pressure for five starts, and another

. alarm if there.is only'. pressure for one start.

Both' alarms are intended to lIndi.cate problems in the. air start' system. The modi fication was completed

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October:20,- 1977 (Drawing Change-Notice A-1610, Nonconforming Report S-318.)

'9.)c.Several ofcthe'new fuel assemblies' loaded into.the core during the first g

refueling' incorporated des'ign modifications that were analyzed by the fuel s

. vendor. Babcock =and = Wilcox, and ' approved by the NRC. The new BT,W design

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? modifies the'end: fittings'of the: fuel assemblies somewhat to improve their

hydraulic characteristics, and ' changed the corners 'of the ' spacer grids to -

L prevent. interferenc,e during fuel 1 handling operations. The changed assemblies are adequate to. cope eith all: accident conditions, and present no safety 1

problem. lTheireview of; this change was completed December 5,1977.

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'(NonconformingiReport 5-697.):

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. 10.)IHodifications' were made ~ to the OnceIThrough Steam' Generator drain and vent

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. lines' to provide lbetter control of water chemistry during startup. Two.

of the idrain. lines were, separated : from the. drain header and routed by Class L1 lines ithrough' a~ reactor building ' penetration and into the main

-condenser. Proper. isolation was_ provided -for-these lines, which will-

.act qas' blow'dcwn -lines for the 'OTSG's, and with proper class 1 design'. the

. probabili ty or. consequences' of-accidents are not increased. The modification

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was. handled.by~several: design'pa.:kages which were completed at'various times.

-(Drawing' Change' Notice A-976(5-26-77), Drawing Change Notice A-992(3-24-77),

Drawing. Change Notice A-1071(8-12-77), and. Drawing Change Notice A-910

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' Major" Items of ~ Safety = Related Maintenance fl.) L.The local switch fo-Reactor Building Emergency' Cooling Unit A-500C

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vas binding:and would - not operate -properly. The pistol grip switch "was cleaned and lubricated, Jand was returned to service on February 1.

J(Work Requestr 018377)-

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2;). The piston on main'~ steam line snubber MS-20521-SW13 was noticed to be

sticking.. Disassembly of the accumulator revealed dirt in the cylinder and' grooves worn in the cylinder valls.

fThe cylinder was replaced.

-(Work Request 019237) 3.): During-a calibration test for RPS' Channel D,ca defective transistor

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was. discovered in the Flux / Imbalance / Flow trip bistable. The transistor was replaced, returning-the unit to service on March 28.

(Work Request

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017786).

4 4.),l An ? inoperable RPS pressure transmitter was sent to' the manufacturer for

repair.and calibration,1 being returned to service on June 13.

(Work Request-019728) 5.)

Pressurizer-spray control valve PV-21509 would not operate and required replacement of the drive sleeve and handwheel assembly.

The1 valve.-was returned to service June 7.

(Work Request 019027) 6.); - The pressurizer spray bypass valve had galled, causing leakage and preventing;it from being adjusted.

The valve was repaired, and a

cap was installed-and seal welded to prevent leakage. Work was com-pleted May 25.

(Work Request 020856)

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7.)

The. pressurizer _. sample line isolation valve (SFV-70001) would not clo'se on control room signal. - A broken drive sleeve had to be replaced,

. returning.the valve-to service on September 24.

(Work Request 024954) 8.)

The -pressurizer code safety valve (PSV-21506) was. lifting at 2200 PSIC, welt below its setpoint of 2500 PSIG. The seat disc and-diaphram were.

-replaced,-and_the.setpoint was properly adjusted.

(Work Request 015564)

9.)- Pressurizer code safety valve PSV-21507 was leaking through, requiring.

the ' seats ' to. be-lappe'd. !(Work Request 018750)

' 10.'); : buring the re' fueling outage which-began August 20, functional testing

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?of: hydraulic snubbers-was1 performed.1 Thirty-five. of the eighty-one

, snubbers tested 1 required somt. type of maintenance (rebuild, repair, adjustment)ibefore' they"wo~uld pass the test and be returned -to service.

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11.)

The-. outlet = valve SFV-26039 from a Decay Heat Cooler would not close-properlyJdue to a brokenL torque switch.

The switch was replaced, and i

the.. valve returned to service o'n October 25. '(Work Request 026267) 4 J10.

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12.),. During the ' reactor. building integrated leakage rate test performed in early October,11977, leakage was detected -into the Nuclear Service

Cooling Water System, which isfclosed to the l atmosphere. Th'e leakage 5

did not invalidate' test results, but might have affected reactor building emergency cooler. operation. Head bolts on all four cooler units were retorqued, and caps: vere placed on vent valves' for three of the coolers.

(Wcrk' Requests.026423, 026424', 026425, 026426) 13.) A drain. valve on a Decay Heat Cooler. outlet line, DHS-523, developed

.a-pinhole leak at the weld to the line. The hole was ground out and rewelded. -~(Work ' Request 026262) 14.)

The Borated' Water. Storage Tank isolation valve SFV-25003 failed to

- respond'to~ control room signal.

Inspection showed damage to the operator clutch. assembly, requiring replacement. Inspection of the redundant valve, SFV-25004, revealed similar damage but to a lesser 3

extent. The damaged parts of that operator were also. replaced.

(Work Requests 022582, 026545) 15.) ' A check 'of Reactor Coolant Pump 'undervoltage and phase balance relays (pump. monitors) showed that two-phase balance relays had failed non-conservatively.. One of the units was replaced, the other was recali-

' b rated.

(Work Request 025716) 16.)..One of -the ~ reactor coolant pump hydraulic snubbers (six per pump) was 'found to have the fluid accumulator dry during a surveillance

' inspection. -The point of. leakage was isolated to an 0-ring that was

' made of an improper material.. The seals and 0-rings in the snubber werc replaced,: returning the unit'to service.

(Reportable Occurrence 77-16)

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17.)- During the; refueling outage, eddy current inspections were performed on both once Through Steam Generators. Several indications were dis-covered, resulting in the plugging of eight tubes.in the A steam generator.

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