IR 05000255/1990023
| ML18057A503 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/25/1990 |
| From: | Danielson D, James Gavula NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML18057A502 | List: |
| References | |
| 50-255-90-23, IEB-79-14, NUDOCS 9010050186 | |
| Download: ML18057A503 (5) | |
Text
U. S. NUCLEAR REGULATORY COMMISSION REGION II I Report No. 50-255/90023(DRS)
Docket No. 50-255 License No. DPR-20 Licensee:
Consumers Power Company 1945 West Parnall Road Jackson, MI 49201 Facility Name:
Palisades Nuclear Generating Plant Inspection At:
Bechtel Power Corporation, Gaithersburg, MD Inspection Conducted:
September 4-6, 1990 - Bechtel Power Corporation August 30, 1990 - NRC Headquarters Inspector:
Approved By:
Materials and Processes Section Inspection Summary 9~Z.J-9tJ Date Inspection on August 30 through September 6, 1990 (Report No. 50-255/90023(DRS))
Areas Inspected:
Special safety inspection of licensee action associated with the Safety-Related Piping Reverification -Program (37701).
Piping and pipe support evaluations were reviewed for ad~quac Results:
No violations or deviations were identified. During the course of the inspection, the following strengths and weaknesses were noted:
0
Because of the higher than expected re-analysis rates, the licensee acknowledged a potential for over-extension of the project management staff for oversight of its contractor The extent of the Phase I portion of the reverification program was apparently not well understood by the licensee at the time the commitment was made to the NR Recent independent design verification activities are much more comprehensive than previous efforts.
t DETAILS Persons Contacted Consumers Power Company (CPCo)
D. Malone, Plant Project Support Supervisor M. Cimock, Plant Project Senior Engineer Bechtel Corporation R. Mays, Project Engineer R. Jackson, Engineering Manager R. Awan, Group Supervisor S. Kalavar, Plant Design Staff N. Kalyanam, Assistant Project Engineer J. Brother, Chief Quality Engineer D. Kasa 1, Manager, Qua 1 i ty Assurance Nuclear Regulatory Commission (NRC)
B. Holian, Palisades Project Manager, NRR A. Lee, Mechanical Engineer, NRR J. Petrosino, Vendor Inspection Branch Inspector, NRR Safety-Related Piping Reverification Program (SRPRP) Review Background During a 1989 NRC inspection of Palisades* snubber reduction design efforts, the validity of the calculations used as the design bases for these analyses was questione These calculations were, for the most part, performed for IE Bulletin (IEB) 79-14 during the 1979-1981 time fram Because of the extent and fundamental nature of the errors found in these calculations, additional inspections to specifically review IEB 79-14 records were performed in order.to evaluate the significance of the proble Based on the findings from these inspections, CPCo committed to perform a comprehensive review of a portion of their safety-related piping systems in order to.
verify the adequacy of the existing plant configuration Management Meeting to Review Preliminary Results of SRPRP A meeting was held on August 30, 1990, at the NRC Headquarters offices with representatives from CPCo, NRR and Region III staff member This meeting was requested by CPCo to provide interim results of the piping reverification progra To date, five of the original 18 subsystems in the Phase I program have been completely reconcile Of the five, three subsystems contained discrepancies which required a new computer analysis of the pipin The reanalyses resulted in significant support load increases which would require seven support modifications to return the systems to within FSAR
., * *
commitment The other two subsystems had discrepancies which were reconciled using hand calculations onl Eight other subsystems have undergone partial reconciliation evaluations to demonstrate acceptability with regard to interim operability criteri Review of Piping and Pipe Support Calculations The following calculations were reviewed for compliance with NRC requirements and licensee commitments:
0 As-Built Reconciliation Report #03356, "Auxiliary Feed Pump Suction", August 17, 199 As-Built Reconciliation Report #03360, "Low Pressure Safety Injection", August 16, 199 These two analyses were reconciled to FSAR criteria. The discrepancies in the first package which hctd to be evaluated included locations uf supports, spring settings and nozzle thermal movement All of these discrepancies were reconciled using simple hand calculation No modifications were require The discrepancies in the second package which had to be evaluated, included an unanalyzed restraint, valve weights, seismic response spectra, and seismic anchor movement These discrepancies required a new computer analysi A total of five support modifications will be required to return the piping system to within FSAR requirements.
0 Calculation No. PD-GS-90-003, "H.P. Safety Injection Piping (Short Term Operability)", August 21, 199 Calculation No. PD-GS-90-006, "Safety Injection Bottle to Primary Loops lA, 2A, lB, and 2B
, AugustlO, 199 These two calculations were performed to confirm short term operability onl The piping analysis for the first system could not be readily retrieved, therefore a new analysis was required to reconcile the as-built configuratio Because of excessive gaps in the Z direction, two of the supports were initially considered inactive in the analysi Subsequent analyses indicated that a total of six supports would need to be considered inactive because they exceeded the pipe support operability criteria. Operability was eventually demonstrated after several iteration For the second calculation, a new piping analysis was required to reconcile multiple design and as-built discrepancie These discrepancies included seismic anchor motions, stress intensificcttion factors, seismic response spectra, thermal anchor movements ctnd excessive support gap Three supports were considered inactive in the analysi The resulting piping stresses marginally exceeded FSAR 1 imits but were we 11 within the interim operabi 1 ity criteria.
'
During the reviews of the above calculations, several comments were made by the NRC inspector regarding minor oversights in the calculatio These oversights did not alter the conclusion of any of the analyse In general, the calculations were well documented and no deficiencies were note.
Deviation Report Review During the course of the support inspections being performed under SRPRP, the licensee discovered gross deformation of pipe supports GCI-H747 and GCI-H76 These restraints support risers that are attached to two of the four Safety Injection Bottles inside containmen The wide flange structural members had buckled, the riser clamps were bent in the strong direction and threaded rods exhibited obvious neckin The cause of the observed damage according to Palisades Deviation Report No. D-PAL-90-098 was attributed to a waterhammer event, most likely in 198 The NRC inspector reviewed Palisades Calculation EA-SC-90-094-01, Revision 0, April 26, 1990, "Support GCI-H765(Q) Evaluation
- This calculation documents the new support design which replaced the damaged support The overall support configuration.was maintained; however, heavier structural sections and heavier pipe clamps were utilized to increase the safety margin of the desig In addition, the NRC inspector reviewed Bechtel Calculation N PD-GH-90-3365-001, Revision 0, May 29, 1990, 11Qualification of Pipe Support No. GC-l-H765 and GC-l-H747
- The purpose of this calculation was to evaluate the operability of the support, given the damaged condition Since the supports were replaced prior to restarting the unit, the evaluation was performed to assess past operability as opposed to justifying interim operatio During the review, the following questions were raised:
c Based on the observed deformation with only one wide flange being deformed, why is it valid to assume that the load will equally split between the two beams?
In the deviation report event description section, the discussion refers to 11 cracklike weld indications for welds connecting the Y-flange to the shelf on the liner.
How is this factored into the weld evaluation?
Subsequent NRC inspection at Bechtel Gaithersburg for this same system revealed that additional as-built and design discrepancies also existed in the piping analysis associated with this hange It was noted during the inspection that these other items were not factored back into the previous operability evaluatio Pending a review of the licensee's action to evaluate the consequences of this aspect as well as the above noted questions, this will be considered an Unresolved Item (255/90023-01).
No violations or deviations were noted.
- Unresolved Items An unresolved item is a matter about which more information is required in order_ to ascertain whether it is an acceptable item, an open item, a deviation, or a violatio The unresolved item disclosed during this inspection is discussed in Paragraph 3 of this repor.
Exit Interview The Region III inspector met with licensee representatives (denoted in Paragraph 1) at the conclusion of the inspection on September 6, 199 The inspector summarized the purpose and findings of the inspectio The licensee representatives acknowledged this informatio The inspector also discussed the likely informational content of the inspection report with regard to documents or processes reviewed during the inspectio The licensee representatives did not identify any such documents/processes as
- proprietary.
5