IR 05000295/1988010

Insp Repts 50-295/88-10 & 50-304/88-11 on 880405-21. Violations Noted.Major Areas Inspected:Previous Insp Findings,Lers & Snubber Surveillance & Functional Testing

ML20154M210
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	05/24/1988
From:	Danielson D, James Gavula NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20154M181	List: IR 05000295/1988010 ML20154M179 ML20154M196
References
50-295-88-10, 50-304-88-11, NUDOCS 8806010208
Download: ML20154M210 (15)

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U. S. NUCLEAR REGULATORY COMMISSION

REGION III

Reports No. 50-295/88010(DRS); 50-304/88011(DRS)

Dodet Nos. 50-295; 50-304 Licenses No. DPR-39; DPR-48 Licensee: Commonwealth Edison Company P. O. Box 767 Chicago, IL 60690 Facility Name: Zion Station, Units 1 and 2 Inspection At: Zion Site, Zion, Illinois Sargent and Lundy Office, Chicago, Illinois Inspection Conducted: April 5-6, 13-14 and 21, 1988 at Zion April 19, 1988 at Sargent and Lundy Inspector: >

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6 V PT Date Approved By: D. H. Danielson, Chief Materials and Processes f 4 /' N '

Date Section Inspection Summary Inspection on April 5-21, 1988 (Reports No. 50-295/88010(DRS);

No. 50-304/88011(DRS)

Areas Inspected: Special inspection of licensee's action on previous inspection findings, licensee event reports and snubber surveillance and functional testing. (70370, 92701, 92702)

Results: Two apparent violations were identified (inadequate design control - Paragraph 2.f, and inadequate review for Technical Specificaion i

requirements - Paragraph 3.b).  !

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DETAILS Persons Contacted Commonwealth Edison Company (CECO)

• Plim1, Station Manager

• Cascarano, Technical Staff Supervisor

• Pedleckas, Technical Staff Engineer

• J. Reiss, Field Engineering Supervisor L. Lentine, PWR Licensing Supervisor i

Sargent and Lundy Engineers (S&L)

A. Walser, Senior Structural Project Engineer S. Putman, Supervising Design Engineer R. Krawczyk, Project Engineer R. Hameetman, Project Engineer Westinghouse P. Kotwicki, Piping Technology S. Palm, Manager-Structural Analysis F. Loceff, Manager-Plant Engineering Department O'Donnell and Associates, Inc. (O'Donnell)

E. Hampton, Vice President R. Raco, Senior Consultant J. Breen, Stress Analyst J. Gribik, Consulting Engineering Offir2r Paul-Munroe Enertech J. Raymant, Vice President A. Shekomz, Engineering Manager

• Denotes those attending exit meeting on April 21, 1988 at Zio . Action on Previous Inspection Findings (Closed) Violation (304/87012-01A&B): Procedure TSS 15.6.48 did not specify allowable ambient temperature for performing snubber functional tests and did not account for the operating environment of hydraulic snubbers when specifying acceptance criteri The NRC inspector reviewed relevant portions of Revision 17 of the above procedur The corrective actions, as stated in Ceco's response dated Oc'.ober 1, 1987, were determined to be adequate and found to be properly implemented. On this basis, this item is considered close , .. . - . . ..

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. (Closed) Unresolved Item (304/87012-02): Procedure TSS 15.6.48 did not specify any quantitative acceptance criteria to verify proper piston movement for small bore hydraulic snubber Based on a September 28, 1987, letter from Grinnell Corporation to Mr. J. Reiss of Ceco, "drag force is not normally required for production units and/or rebuilt using Grinnell replacement parts and procedures . . .

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. The requirement to specify a quantitative acceptance criteria to verify proper piston movement appears to be unnecessary. This item is therefore considered close (Closed) Unresolved Item (304/87012-03) The 100 inch per minute (ipm) acceptance criteria specified in TSS 15.6.48 did not have any technical justification from the snubber manufacturer. In specifying the acceptance criteria, CECO verified that the piping could accommodate the 100 ipm velocity but failed to verify that the snubber itself could properly function at that rat Since the time that this item was identified, CECO has revised the small bore snubber functional test criteria down to a maximum lo :k-up velocity of 40 ip In addition, the NRC inspector reviewed a July 20, 1977, letter from ITT Grinnell Corporation to Mr. W. Wogsland at CECO's Zion Station. Although the maximum lock-up velocity discussed in the letter is 30 ipm a statement is made "that the decision of hydraulic shock suppressor operability must be made at the A.E. or utility level". On this basis, CECO's decision to define the operability limit at 100 ipm could be subjectively justified, even though there was and still is no technical justification for i Based on the above discussion this item is considered closed, (Closed) Violation (304/87012-04): CECO did not have a procedure that prescribed the type or extent of the engineering evaluations required by Technical Specification (Tech Spec) Paragraph 4.22.1. The NRC inspector reviewed selected portions of TSS 15.6.48

"Hydraulic and Mechanical Snubbers Surveillance," Revision 17, February 18, 1988. The corrective actions, as stated in Ceco's response dated October 1, 1987, were determined to be adequate and found to be properly implemented. Based on this review, this item is considered close (Closed) Open Item (295/87006-02; 304/87007-02): Licensee Event Report (LER) 295/87003 documented an inoperable snubber due to personnel error. An engineering analysis was performed to evaluate the consequence of this situatio The NRC inspector reviewed relevant portions of S&L's report,

"Piping Operability Report, Disconnected Snubber No. RHRS-1129, Subsystem RH-02, Zion 1," EMD-062249, Revision 00, April 8, 198 ;

The analysis reevaluated the previous Stone and Webster (S&W) '

calculation by modeling the portion of the pipe system affected by l

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the snubber in question and assumed the snubber did not functio The results indicated that piping stresses were all within code allowables and that some minor load increases were taken by adjacent-support In some cases the correlation between the S&L analysis and the S&W analysis was not precise, however, it was concluded that the system could have performed its designed function. The NRC inspector concurred with this conclusio This item is considered closed, (Closed) Open Item (295/87028-01; 304/87029-01): Containment hydrogen monitoring sample piping was modified and left in an unsecured condition. As a result of the above item, S&L conducted an analysis of a temporary modification implemented by the station to resecure the pipin The NRC inspector reviewed relevant portions of S&L's Report,

"Hydrogen Monitoring System, Zion 1 and 2," EMD-064019, Revision 00, August 13, 1987. The results indicated that with'the temporary restraint in place, the piping stresses would meet faulted stress allowables for a safe shutdown earthquak It was noted by the NRC inspector that no analysis was performed to evaluate the piping system for previous operability concern Without such an evaluation, the safety significance of the previous I unrestrained condition cannot be determined. Also, the subject hydrogen monitoring system penetrates containn.ent and therefore, according to the FSAR, was designed as Class I piping for a certain distance in proximity to the containment penetration. Since no evaluation had been performed at the time when the restraints were removed from the piping system, the potential impact on the containment penetration had not been determined. This is an apparent lack of design control and is considered a Violation (295/88010-01; 304/88011-01).

l Action on Licensee Event Reports (LER) i (Closed) LER (295/88007) Steam generator hydraulic snubbers failed to meet the functional acceptance criteria due to particulates in the hydraulic flui Currently, the exact cause of the fluid contamination has not been determined. This aspect is being tracked under Open Item 295/88010-03; 304/88011-03. See Paragraph 4. for additional informatio . Snubber Visual and Functional Testing Small Bore Snubbers (1) Visual Examinations As specified in Technical Specification Paragraph 4.22.2.A.1, and as implemented by Procedure TSS 15.6.48, all hydraulic snubbers were visually inspected. Accessible snubbers were

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inspected during October and November 1987 in order to meet a 12 month inspection interval. This reduced interval was due {

to one snubber being identified as inoperable during the last outag The latest inspection also identified one inoperable snubber and will require the inspection interval to stay at 12 month Inaccessible snubber inspections were performed durin'g the ;

current refueling outage and were completed by March 5,198 During these inspections 11 hydraulic snubbers were identified as being inoperable. This caused the visual inspection interval to be reduced to 62 days i 25%. In addition to the inoperable snubbers, approximately 84 snubbers were noted as having reservoirs less than 50% full or having major hydraulic fluid leak All mechanical snubbers were inspected and noted as being acceptabl No violations or deviations were noted during the NRC inspector's reviews of the above informatio (2) Functional Snubber Tests From the reauired sample of ten hydraulic snubbers functionally tested, snubber No. ASRS 1107 failed to exhibit free piston movement. The snubber locked-up in tension and compression due to potentially mis-adjusted locking valve screws. An analysis was subsequently performed by S&L which verified that the piping had not been adversely affected by l this failure to move. The conclusions of this evaluation are i documented in S&L's letter dated May 4, 1988, to D. Wozniak !

of CEC I An additional ten snubbers were selected and tested as I required by Technical Specifications. From this sample, {

snubber No. ASRS-1109 failed to lock-up in the tension direction. A third sample was then selected, and tested with all snubbers meeting the acceptance criteri l No violations or deviations were noted by the NRC inspector during reviews of the above informatio (3) Snubber Service Life Monitoring i

Technical Specification Paragraph 4.22.3 states that once I every 18 months "the installation and maintenance records for each snubber shall be reviewed to verify that the indicated service life has not been exceeded or will not be exceeded prior to the next scheduled snubber service life revie If the indicated service life will be exceeded prior to the next scheduled snubber service life review, the snubber service life

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shall be reevaluated or the snubber shall be replaced or reconditioned so as to extend its service life beyond the date of toe next scheduled service life review."

During this outage, approximately 61 snubbers were rebuilt to meet this requirement. The current recommended service life for the snubber's seal material is five to seven year All of the above snubbers had been reconditioned in the Spring of 1981 and therefore required reconditionir.g this outag However, based on the NRC inspector's review of the Unit 1,

"Snubber Overhaul Trending," dated April 13, 1988, approximately 140 snubbers rebuilt in the Spring of 1982 will exceed the recommended service life of seven years by the time Unit I refuels in the Fall of 198 Contrary to the requirements of the Technical Specifications these snubbers were not replaced, or reconditioned and the snubber service life was not reevaluated to extend the service life. This is a violation of the Technical Specification requirement (295/88010-02; 304/86011-02)

It should be noted that approximately 40% of the 1981 vintage snubbers required some type of reconditioning prior to reaching the seven year recommended life. Approximately the same percentage of 1982 vintage snubbers have also been reconditioned due to potential problems. Furthermore, of the 12 inoperable j snubbers discovered during this outage eight were last rebuilt in 1982. Based on this information, there does not appear to be a sufficient basis for extending the current recommended service life beyond seven year Except as noted, no violations or deviations were identifie Large Bore Steam Generator Snubbers (1) Procedure and Documentation Review The NRC inspector reviewed selected portions of the following procedure * "S/G Snubber Testing Utilizing Conventional Test-in place," No. TSSP 22-88, March 15, 198 * "S/G Snubber Testing Utilizing the API Test Machine,"

No. TSSP 36-88, April 5, 198 * "Steam Generator Snubber Testing," No. TSS 15.6.86, April 2, 198 Acceptance criteria was adequately delineated and acceptable instructions were provided for performing the functional test . . . _ _ _ _ . .

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In addition, documentation for the verification and validation of the functional test equipment computer programs, as required by Zion Procedure ZAP 3-54-1, was reviewed. All the required documentation was in place. It was noted by the NRC inspector that the Wyle verification and validation process was a docun.ented comparison between 1.he computerized test results and the manual snubber tesL results. In contrast, the Paul-Munroe verification and validation process was a review of the equations utilized in the computer sof tware. Based on discussions with the licensee, future verification and validation will consist of a more rigorous process similar to Wyle' The calibration documentation was also reviewed by the NRC inspecto * Wyle's, API #2, "In-Place Snubber Test System" was due for calibration on August 10, 1988, and was within calibration requirement * Paul-Munroe's, TESTAN II, Serial No. 1501, "Test In-Place Console" was due for calibration on March 15, 1989, and was within calibration requirement It was noted by the NRC inspector that the calibration tolerance specified by Paul-Munroe for the TESTAN II Test Machine was i 2% of full scale. Since velocity is determined by flow, and the full scale range of the flowmeter is 10 gallons per minute (gpm), the flow tolerance is 10.2 gp For the Zion steam generator snubbers, this would equate to approximately 1 0.5 inches per minute (ipm) variation in the i lock-up and bleed velocitie Since the bleed rate acceptance l criteria ranges from 0.02 to 0.18 ipm, it is clear that this l large of a calibration tolerance cannot be accepte j l

The NRC inspector reviewed the actual calibration data for the '

flowmeter in question and found the tolerance to be significantly less than the value specifie Based on this i review, a sufficient accuracy was obtained to measure the l required flows. Based on discussions with the licensee, this aspect of the calibration certification will be changed to reflect the overall test accuracy for future wor No violations or deviations were identifie (2) Functional Snubber Tests As required by Technical Specifications, one large bore hydraulic snubber was tested during the outage. This snubber, N , failed to meet the acceptance criteria as well as the next three snubbers that were tested. Upon investigating the cause of the fa lures, it was determined that the hydraulic i

fluid in the snubbers was contaminated with both metallic and

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non-metallic particle This contamination was of sufficient size to plug the bleed ports on the snubber control valve _l Based on this information, all 16 steam generator snubbers were functionally tested and control valves with larger bleed portf were installed in all 16 snubber As a result of the snubber failures with extremely low and potentially no bleed rates, an evaluation of the steam l

, generator system was conducted. This evaluation was to determine if any associated components had been adversely affected for Unit 1 and to establish the operebility of_the Unit 2 steam generators which potentially have the same  !

proble l The evaluations were conducted by Westinghouse, S&L, and O'Donnell and addressed the steam generator nozzles, steam generator support structures, reactor coolant piping, m&in steam piping, and feedwater piping. The results of these analyses were presented in a meeting on April 19, 1988, to the Regional staff. Relevant portions of the presentation material are included in Attachment A of this report. Specific detail of the analyses were discussed with the technical staff in NRR and the acceptability of the licensee's evaluation approach was established. The assumptions and methodologies used in the analyses appeared to be conservative and represented a worst case evaluation. The results concluded that safe shutdown capability was positively demonstrate ,

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At the conclusion of the inspection, the root cause of the hydraulic fluid contamination had still not been determine Pending additional investigations into the source of the contamination and whether Unit 2 steam generator snubber have the same problem, this will be considered an Open Item (295/88010-03; 304/88011-03).

l Open Items Open items are matters which have been discussed with the licensee which l will be reviewed further by the inspector, and which involves some action on the part of the NRC or licensee or bot The open item disclosed during this inspection is discussed in Paragraph 4. . Exit Interview The Region III inspector met with the licensee representatives (denoted ,

l in Paragraph 1) at the conclusion of the inspectbn. The inspector ~, ,,

summarized the purpose and findings of the inspection. The licensee representatives acknowledged this informatior. The inspector also discussed the likely informational content oJ the inspection report with regard to documents or processes reviewed during the inspectio The licensee representatives did not identify any such documents /

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YTT A Cilh ENT r

O'DONNELL & ASSOCIATES,IN .

SCENARIO

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. AN EVENT OCCURS WHICH LOCKS THE STEAM GENERATOR .

SNUBBERS AND CAUSES A PLANT SHUTDOW THE SNUBBERS FAIL TO BLEED DOWN AS THE PRIMARY AND SECONDARY COOLING SYSTEMS CONTRACT, THE STEAb GENERATOR HORIZONTAL MOVEMENT IS RESTRAINED BY THE LOCKED SNUBBERS AND IS PREVENTED FROM RETURNING T0 ITS "COLD" POSITIO ANALYSIS:

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DETERMINE THE MAGNiiUDES OF THE:

e STRESSES IN THE PIPING e FORCES AND MOMENTS ON THE EQUIPMENT N0ZZLES e LOADINGS ON THE PIPE SUPPORTS AND THE EQUIPMENT SUPPORTS l

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STEAM GENERATOR IM_ET N0ZZLE ACIU '__ AliOWABLES P = 1140 KIPS AXIAL 1200 KIPS V = 350 KIPS SHEAR 900 KIPS M =

72000 IN. KIPS BENDING 78000 IN. KIPS T = 4870 IN. KIPS TORSIONAL 25000 IN. KIPS

l REACTOR VESSEL OUTLET N0ZZLE i

ACTUAL Al I (MABLES 996 KIPS FX = 2302 KIPS (AXIAL)

648 KIPS FY =

763 KIPS 7 KIPS FZ = 173 KIPS

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255 IN. KIPS MX =

16020 IN. KIPS  !

\ l 5275 IN. KIPS MY = 18514 IN. KIPS

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46545 IN KIPS MZ =

73390 IN. KIPS THESE ARE TE RESULTS FROM THE TWO HIGEST LOADED N0ZZLE i i

ALL OTHER PRIMARY EQUIPENT N0ZZLES ALS0 EET THE ALLOWABLE l l

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EVALUATION OF NSSS SUPPORTS FOR SGS LOCK UP EVENT

o SG COLUMNS MUST ABSORB TILT OF STEAM GENERATOR

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o IMPACT ON OTHER SUPPORTS IS LESS THAN DESIGN BASIS LOADS o SG COLUMNS ARE THE CONTROLLING ELEMENTS IN THE SUPPORTS FOR THE SGS LOCK UP EVENT

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TENSION COLUMNS o STRETCHY ANCHOR B0lIS (A36) ARE PROVIDED IN THE COLUMNS AS ENERGY ABSORBING ELEMENTS o WESTINGHOUSE TENSION COLUMN LOADS ARE GREATER THAN THE ANCHOR BOLT YlELD LOAD: 890 K!PS > 670 KlPS o ANCHOR BOLT TENSILE STRAINS ARE A MAXIMUM 0F .004 IN/IN OR 3.3 6 Y o THIS LOW STRAIN LEVEL IS ACCEPTABLE FOR THE ONE TIME SGS LOCK UP EVENT o LIMITED YlELDING 0F TENSION COLUMNS SOFTENS THE COLUMN SYSTEM AND REDUCES LOADS

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