IR 05000254/1972009

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Insp Repts 50-254/72-09 & 50-265/72-09 on 720825-27,0907 & 28.No Noncompliance Noted.Major Areas Inspected:Events, Investigation & Corrective Measures Re Unit 2 Jet Pump Failure on 720820
ML20235E534
Person / Time
Site: Quad Cities, 05000000
Issue date: 10/20/1972
From: Hunnicutt D, Jordan E
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20235B311 List: ... further results
References
FOIA-87-111 50-254-72-09, 50-254-72-9, 50-265-72-09, 50-265-72-9, NUDOCS 8709280158
Download: ML20235E534 (17)
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U. S.. ATOMIC ENERGY COMMISSION DIRECTORATE OF REGULATORY OPERATIONS

REGION III

RO Inspection Report No. 050-265_/72-09 RO Inspection Report No. g 254/72- M Litensee Conunonwealth Edison Company P. O. Box 767 

,           Chicago, 113inois 60690
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Quad-Cities Nuclear Power Station License Nos. DPR-29 Units 1 and 2 and DPR-30 Cordova, Illinois Category: B R # 

*-             GE (BWR) 809 Hve, 2511 Mwt Type of Licensee:

Type of Inspection: Special, Unannounced Dat es of Inspection: August 25 - 27, September 7 and 28, 1972 Dates of Previous Inspection: August 10 - 11, 16 and 17, 1972 Principal Inspector ~ /8 o 7 '(Da(e) Accompanying Inspectors: None Other Accompanying Personnel: None Reviewed By: 

           .b N D. M. Hunnicutt, Chief  M/bO/71 Reactor Testing and Startup Branch  '(Datd)
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8709280158 870921 PDR FOIA MENZ87-111 PDR 

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SUMMARY OF FINDINGS 

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Enforcement Action: None j Licensee Action on Previously Identified Enforcement Matters: None i Design Changes None j Unusual Occurrenc3s Jet Pump Failure on August 20. 1972 l An unbalance in recirculation loop flow was detected about 11 August 20, 1972, during a restart of recirculation pump "B". Investiga-tien by the licensee revealed abnormal flow indication on jet pump N . An orderly shutdown of Unit 2 reactor was started at 12:45 August 21, 1972. The reactor has remained shutdown since this occurrence for investigation and correction of the jet pump failur The . licensee has found that jet pump No.17 had been displaced from its normal position due to loosening of the beam bolt assembly which normally holds the pump in position. The beam bolt loosening has been attributed to inadequate tack welds and/or improper tensioning of the beam assembly during installatio (Paragraphs 1 - 12)  ; The licensee has inspected all Unit 2 jet pumps and has initiated repairs and measures to prevent similar failures. The licensee presently schedules restart for the week of October 9, 197 Other Significant Findings Current Findings Although detection and analysis of the jet pump failure appeared to be timely, the licensee's surveillance procedure and the Technical Specifications were found to be inadequate to identify a jet pump failure such as occurred August 20, 1972. (Paragraph 3) Results lof jet pump inspections (Paragraph 7) indicate inade-quate quality assurance (tack nelds and beam tensioning) during i 

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jet pump assembl . Analysis of ef fects of unrecovered disc and retainer upon reactor safety was incomplet (Paragraph 8) 

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 . , Jet pumps.Nos. 10, 11, 32,'14 16, and 17 repairs were incomplet p"   (Paragrapli 9)    } l
' . Vibration instrumentation on jet pumps' Nos.11 and 12 may be  j damaged during jet pump repairs. (Paragraph 9) .

B. . Status of Previously Reported Unresolved Items: N/A 

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q Management Interview 

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       .t A .' - Auaust 26. 1972     I The inspector discussed the findings of the vessel inspection
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  (Paragraph 4) and the detection of the jet pump failure (Paragraph 2)?

with Mr. Palme September 7. 1972 The inspector' discussed the jet pump inspection results (Paragraph 7) and the initial installation records (Paragraph 6) .with Messr , Palmer and Stephenson. The inspector stated that the differences 

  ' between the inspection results and the installation records appeared to illustrate inadequacies in the construction quality assurance program. . The inspector asked the licensee to consider additional surveillance test measures to assure Unit 'l jet pump operability in
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view of the' nature of Unit 2 failure (Paragraph 12) Mr. Palmer 

,  agreed to consider additional surveillance measure September 28, 1972  " The inspector discussed jet pump repairs (Paragraph 9) with Messr Palmer and Stephenson. .The inspector. stated concern regarding unrecovered components.(Paragraph 8). Mr. Palmer stated that a safety analysis of unrecovered components would be completed before .

Unit 2 operation is resumed. The inspector stated concern regarding 

. probable loss of jet pump 11 and 12 vibration instrumentation
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  (Paragraph 9). Mr. Palmer stated that every effort was being made to preserve the sensors but assurance of jet pump integrity was evaluated by CE to be more important than additional vibration' test dat !

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f REPORT DETAILS 

. Persons Contacted Commonwe.alth Edison Company (CE)

F. Palmer, Operations Superintendent B. Stephenson, Assistant Operations Superintendent V. Schlosser, Plant Maintenance Engineer N. Kalivianakis, Operating Engineer K. Houseman, Technical Staff Engineer R. Newkirk, Technical Staff Supervisor General Electric Company (GE) R. Murkowski, Jet Pump Design Engineer (San Jose) J. Macpherson, Reactor Internals Engineer (San Jose) R. Leasburg, Project Manager Jet Pump Failure. August 20. 1972 Reactor Status Precedina Occurrence Review of strip chart recorder tracas and control room logs showed Unit 2 was operating at approximately 80% of full power preceding a "2B" recirculation pump trip at 6:20 p.m. on October 20, 197 The pump was restarted and the load was returned to- 650 Mwe by 7:15 p.m. A second "2B" pump trip occurred at 7:52 p.m. In both pump trips, the recirculation flow decayed normally with no flow increase. The pump trip was found to be caused by an erroneous high oil temperature indication in the hydraulic speed control unit. A licensee representative stated that the temperature sensors have been replaced since this occurrenc . Detection of Jet P sp Failure Recirculation pump "2B" was restarted at 10:15 p.m. following the second trip. The . circulation flows were found to be unbalanced at the same pump speed during flow increase in " local manual" control. The licensee switched from "B" to "A" GMAC for reactor level control due to noisy behavior of the "B" level control GMA (Noisy behavior was later attributed to upward flow through diffuser and transition piece.) The licensee was found to have reduced power with the recirculation system at 12:00 a.m. (midnight) 

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< i October 20 to check for possible jet pump failure. Rod insertion ' was begun'at 12:25 a.m. October 21. The turbine generator was tripped at 2:42 a.m. and the mode switch was manually positioned to " shutdown" by 5:14 a.m. October 21. The indications of jet pump failure are listed in the attached Table 1. The licensee confirmed that jet pump No.17 apparently had f ailed by observing individual jet pump flow indication during a recirculation pump 2B trip. All "B" loop jet pump flow indications, except jet pump No.17, were observed to drop toward zero as flow reversal occurre This additional information indicated jet pump No.17 to be apparently flowing in reverse even when recirculation pump "B" was runnin . Jet Pump Surveillance ' Testing 

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Review of the records of jet pump surveillance testing which was performed on October 21, 1972, indicated inadequacies in both the licensee's procedure and the Technical Specifications. The pro-cedure requirerients and Technical Specifications Section 4. daily surveillance requirements state that if recirculation loop 

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flow imbalance > 15% and indicated core flow compared with core flow derived from loop flow is > 10% and individual jet pump A p varies, from the reau of all jet pump 4 p by > 10% simultaneously, then the jet pump is inoperable. Ccuparisen of drive flows in Table 1 shows loop B 23% greater than loop A, extrapolation o total driving flow of 58 x 103 gym from licensee's data gave a core flow of - 73 x 106 lb/hr, hence the jet pumps are operable according to the procedure requirements and Technical Specifications Section 4.6.G which requires the three conditions simultaneousl The dynamic behavior of the recirculation system was found to cause one or more jet pumps to vary from the mean flow rate by more than i 4.88% flow (i 10% o p) especially at lower pump speed l i-5-I i 

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In spite of the inadequacy of the surveillance requirements, the-licensee personnel assessed the jet pump No.17 failure correctly and took appropriate actions. . Licensee represes:atives have pro-vided an interim surveillance test procedure to replace the pro- i cedure in use at the-time of the occurrence. (Paragraph 11) The licensee states that chaages to the existing Technical Specifications were being proposed to make the jet pump operability testing more meaningfu The licensee stated that consideration was being given to a sur-veillance test which would compare each test with a baseline or 

,  initial set of test dat i
* Reactor Internals Examination Access to the reactor vessel was available follewing steam dryer i separation removal on August 26, 1972. The inspector examined reactor internals with licenses representatives the same dsy. Jet pump No.17 (Figure 1) was found to be leaning against jet pump No. 16, exposing the riser pipe transition piece and the diffuser section opening ! Cause of Failure
,  - Subsequent inspections and investigation by the licensee attributed 1 the f ailure to inadequate beam bolt keeper tack welds and/or improper i tensioning of the been bolt assembly during installation.- The beam bolt assembly vertically restrains the jet pump (Figure 2). Following failure of the tack welds between the keeper and the lock plate (Figure 3)'the beam bolt apparently loosened until during the trip on August 20, 1972, the beam disengaged from the transition piece stanchions allowing the pump to rise until interference of the
  ' diffuser with the restrainer- restricted upward notion of the pum ,
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The mode of weld failure was determined by metallurgical examinations by GE at San Jose to be metal fatigue. RO:HQ personnel reviewed the metallurgical test results at San Jos . 

~ Initial Installation Records The inspector examined records of initial installation of jet pumps for both Units 1 and 2 which included verification for each pump that the following installations and tack welds were completed and
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inspected: Jet pump throat restrainer adjusting screw field weld Unit 1, 8-17-70, Unit 2, 2-12-71-6- ! I e r- + l 

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Jet pump top inlet retainer bolt shop weld Unit 1. 8-15-70, n . Unit 2, 5-7-71

, Jet: pump throat restrainer keeper tack weld Unit 1,8-15-70, Unit 2, 2-12-71 L Jet pump hold,down (beam bolt) keeper tack weld, tensioner , ) .(3965 + 25' psi), bolt torque (50 ft 1b) Unit 1, 8-13-70, l, Unit 2, 5-6-71- l No discrepancies were found in the initial installation records although details of verification of two welds on each beam bolt ~ or specific tension-for each pump was omitte . Results of Jet Pump' Inspections l The inspector reviewed current inspection records consisting of procedures, individual phap inspection checklists and selected ' 

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videotapes of underwater television inspection. The checkpoints I for each pump were found to have been videotaped and the tapes were viewed by GE and CE engineers who filled out the checklist ~ l> 

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The seven inspection points for each pump are shown on Figures 2, 3, and 4 as circled numbere which correspond to inspection points listed below: 1 Beac bolt keeper tack weld- 

 .2 Second tack weld on bsam bolt   ,

3 Restrainer gate keeper tack weld 4 Second restrainer gate bolt keeper tack weld 5' Beam-pocket fit i 6 Restrainer gate wedge penetration 7 Besa bolt retainer bolt tack weld q 

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Beam bolt and restrainer gste keeper welds were found by the f 

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licensee to be inadequate as listed below: 

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l the retainer plate (Figure 5) which dropped into the jet pump No. 17 ) diffuser during attempted recovery. The retainer plate was subse-quently "found" on the vessel bottom by a television camera which was lowered through jet pu.ap No. 17 diffuser but recovery attempts ; were unsuccessful and the plate is no longer visible. Licensee i representatives stated that a safety analyses of operation with the j unrecovered disc and retainer are underway and vill be completed j be' era Unit 2 operation is resume The inspector was advised during a telephone conversation with licensee representatives on October 9, 1972, that two additional objects had accidentally been broken off of the keeper welding . rig during removal and censistad of cne-half of a cadalum plated- I carbon steel compression nut and a neoprene bukhing. The licensee l representative stated that analyses would be provided for operation ( vith the two objects described above preceding resumption of Unit 2 { operatio . Inspection of Jet Pump No. 17 l Licensee representatives stated that jet pump Ns.17 had received only minor surface scratches during the occurrence and would be reinstalled. Surface radiation dose rates were stated by licensee i representatives to be in the. order of 400 mram/br upon removal from the reactor ~veese . Repair Procedures and Status The licensee was found to have prepared and approved procedures which required breaking all biam bolt keeper tack wolds, (except jet pump No. 20 which was installed by the licensee following a jet pump blackage incident oc April 29,3972) retensioning each beam, retorquaing each beam bolt and installing four tack welds on each beam bolt keeper. The procedures also require application of a 300 ft/lb torque clockwise and counterclockwise upon the conopleted beam bolt and a reinspection of the tack welds after the torque application. The defective restrainer gate keeper tack welds (Paragraph 7) were r4 quired to be repaire The inspector reviewed records of repairs as of September 28, 1972, and found no discrepancies in the documentatio ".'he jet pump repairs were decumented as complete as of September 28, 1972, except for jet pump Nos. 10, 11, 12, 14, 16, and 17 which had not yet been retensioned and tack welded. The tack welds on jet i-9-l 

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f pump Nos. = 10,14 and 16 did not break when deten.sioned, with' 300 j ft/lbs.of torque applied. The licensee was found to have fabricated d a special tool to cut the tack weld. Provisions were made t collect metal chips with an underwater vacuum. Jet pump No.-20 

  - beam was detensioned and the tack welds could not be broken 'with 360 f t/lbs of' torque. - Jet pump No. 20 will be lef t as is following addition .of two' tack welds on the beam bolt keeper. Jet pump No 'and '12 have vibration test instrumentation installed. to measure
  .' displacement at the jet pump elbow relative to the reactor. vesse i
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The licensee removed the sensor from jet pump No.11 to permit recensioning and tack welding. The sensor. assembly was reinstalled 

  . following the repa tre but continuity tests presently indicate the .;

sensor to be inoperable. The licensee has decided to also attempt 1 jet. pump No. 12 repairs based upon the licensee's position that the 

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Unit 2 90% power jet pump elbow vibration test data can be extra- ! polated to the 10C% power condition and potential failure of jet; pump No.12 due te improper tensioning or tack welding represents 

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the greater threat to operational safet ' 1 Personnal Radiation Protection i

The inspector observed work in progress in the reactor cavit Personnel were dressed in full protective clothing as required ! 

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by procedures. Stepoff pads with monitoring provisions were .in use at the boundary of the roped off area. The licensee was j 

. found to be-keeping, the steam dryer and separator wet with sprays ,

to prevent possible airborne contaminatio . Increased Unit 1 Jet Pump Operability Surveillance j

The inspector reviewed Unit 1 jet pump operability surveillance j ' testing records, control room logs and Station Review Board Minutes 

  .after the Unit 2 jet pump failure on August 20, 1972. The Station Review Board (SRB) on September 5, 1972, was found to have recom-mended, and station management implemented, a procedure requiring a jet pump operability test immediately following any Unit i recirculation pump trip in addition to the daily test. The SRB also requested an analysis .of the effects of a jet pump failure upon core floodability and recommended c spot check of Unit 1 jet pump welds during the outage' presently planned for April 1973. On September 8, 1972, the SRB approved recording Unit I recirculation system readings hourly and jet pump operability once each shif On September 11, 1972, the SRB recommended, and station management 3 implemented, hourly jet pump flow readings in addition to the
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No deficiencies were found in'the Unit 1 jet pump surveillance test records. The inspector noted .that the Unic I master flow controller 

  . presently maintains an offset in speed between the two pumps o approximately 5%. Licensee representatives stated that'the offset-was due to the control. system and was under investigation. The inspector also noted one pump. motor watt-meter was reading incor-rectly. Operating personnel; stated that a work request on the
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Attachments: L Table 1 l Figures 1.thru 5 l l l ! ! l l 

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TABLE 1 1 

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INDICATIONS OF FUMP FAILURE PARAMETER LOOP A B PITMP SPEED (RPM) 685 685 (60%) DRIVE FLOW:(GPM) 26 x 103 32 x 103 PUMP MOTOR CURRENT (AMP) 240 280 

,          ;a PUMP AP (PSI)'  65  50 TOTAL JET PUMP FLOW (LBS/HR) 36 x 106 34 x 106 JET PUMP AVG PLOW (LBS/HR) 3.5 x 106 3.1 x 106 REACTOR WATER LEVEL (IN)  30  35 JET PUMP 17 FLOW (LBS/HR)  --

4.6 x 106 i 

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