IR 05000293/1993002
| ML20034F022 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/02/1993 |
| From: | Carrasco J, Gray E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20034F014 | List: |
| References | |
| 50-293-93-02, 50-293-93-2, NUDOCS 9303020205 | |
| Download: ML20034F022 (9) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
REPORT / DOCKET NOS. 50-293/93-02
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LICENSE NO.
DPR-35 LICENSEE:
Boston Edison Company RFD #1 Rocky Hill Road Plymouth, Massachusetts 02360 FACILITY NAME:
Pilgrim Nuclear Power Station INSPECTION AT:
Plymouth, and Braintree, Massachusetts INSPECTION DATES:
Jan 11-15
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INSPECTOR:
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M Neb, Reactor Engineer, Da'te
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Materials Section, EB, DRS
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APPROVED BY:
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E. Harold Gray, Chief, Materials Section, Date
Engineering Branch, DRS Areas Inspected: A safety inspection was conducted to determine whether the licensee's design, installation, and modification of safety related dynamic pipe restraints (DPRs) and static (rigid) pipe suppons were performed in accordance with regulatory requirements, engineering specifications and properly documented instructions. Furthermore, to determine whether the snubber surveillance was performed as required by 10 CFR 50.55a(g) and the
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Technical Specification (TS), the ASME Code Section XI for Inservice Inspection / Inservice Testing (ISI/IST) and license commitments. The replacement of Salt Service Water (SSW)
piping project was also inspected.
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9303020205 930218 PDR ADOCK 0500
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Results: The design of safety related pipe suppons was found to be adequate, properly controlled and the configuration of individual supports were maintained current. Regarding configuration control for the ISI it was noted that there is a deficiency consisting of a series of discrepancies between the ISI isometric drawings and the actual piping configuration, because ISI isometrics were not currently maintained. This is an Unresolved Item (No. 93-02-01) pending the NRC review of the licensee's determination of the extent of the ISI drawing deficiencies and corrective actions. In terms of snubber surveillance procedures, a corrective action to incorporate the ASME Code,Section XI requirements in the pertinent procedures was adequate and complete. The licensee displayed good communication between internal and external organizations engaged in the replacement of the SSW piping project.
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3 1.0 PURPOSE AND SCOPE The purpose of this inspection was to determine whether the licensee's design, installation, and design modification of safety related dynamic pipe restraints (DPRs) and static (rigid)
pipe supports were performed in accordance with regulatory requirements, engineering specifications and properly documented instructions. Furthermore, to determine whether the snubber surveillance was performed as mandated by 10 CFR 50.55a(g) in accordance with Technical Specification (TS); ASME Code Section XI, Inservice Inspection (ISI/IST), Article IWF-5000; and license commitments. This inspection included the review of activities affecting the in-progress replacement of the Salt Service Water (SSW) piping.
2.0 DESIGN AND DESIGN MODIFICATION OF PIPE SUPPORTS Review of Selected Samole of Pine Supports The inspector selected the following sample of pipe supports from the Core Spray (CS) and Residual Heat Removal (RHR) systems for review of critical design attributes.
Piping Revision Piping System Support No.
Support Type
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Drawing No.
No.
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6498-608-1 E0 CS and RHR, Pump H-10-1-41SG Guide (2-Way)
P-215B Discharge H-10-1-110 Rigid H-10-1-40SA Restraint
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6498-o08-2 El CS and RHR, Pump H-14-1-11SR Guide (2-Way)
P-215B Discharge H-14-1-31 Spring Hanger
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H-14-1-15 Spring Hanger
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i 6498-608-3 E0 CS and RHR, Pump H-10-1-125 Spring Hanger
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P-215B Discharge H-10-1-128 Spring Hanger
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6498-667 EO RHR RH-19 Snubber RH-20 Snubber 6498-656 CS and RHR, Pump H-10-1-19 Rigid
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P-2.03A Suction H-10-1-21SR Restraint j
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For these supports, the inspector verified that the proper magnitude and orientation of the
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resultant loads from stress problem No. 608 (parts A and B) were properly used in the i
i design of these pipe supports. The geometric configuration of these individual supports was verified by comparing the as-built drawing with the as-designed drawing. For the computer aided pipe support calculations using the STRUDL" computer program, the analytical model was checked to verify the accuracy of the geometric configuration, material properties and
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input loads. Spot check was performed on key numerical values of a limited sample of the hand calculations to verify that the resultant stresses were within the pertinent code allowable
limits.
Findinys The inspector noted a discrepancy between the as-built and the as-designed weld
configurations of the clip angles connecting structural members for pipe support H-10-1-110.
l The inspector verified that this discrepancy was properly addressed via NCR 87-122. NCR
87-122 identified that the clip angles connecting structural beams were only welded on two l
sides as opposed to three sides, because the third side was not weldable. The disposition of NCR 87-122 was the preparation of calculation C15.0.1983 which demonstrated that welds
on only two sides of the clip angle were acceptable for the load imposed on support H-10-1-l 110. The inspector found the calculation adequate and with conservative assumptions.
Conclusion Based on the review of the limited sample of safety related supports, as is described above in a tabular form, the inspector concluded that their design was adequate, properly controlled i
and the configuration of individual supports was currently maintained.
3.0 ISUIST SNUBBER SURVEILLANCE PROGRAM AT PILGRIM NUCLEAR POWER STATION (70370)
Background Snubbers are restraining devices used to control the movement of pipe and equipment during l
abnormal conditions such as seismic events, turbine trips, safety / relief valve discharge, and I
rapid valve closure. Snubbers permit displacement of the pipe as a result of slow movements such as thermal expansion, but restrains rapid motions such as those induced by earthquakes l
and water hammers. However, while snubbers present convenient solutions in design and i
analysis, the use of snubbers has proven to have many practical and economic disadvantages.
Malfonction of snubbers in the lockup mode during plant operation has the potential to cause j
unanticipated high pipe stresses. Because of hardware problems, snubbers have contributed
to the escalating maintenance, inservice inspection, and testing costs. Industry experience i
has shown that piping systems often have more snubbers than are actually required for protecting the piping from carthquakes. Utilities have been undergoing snubber reduction programs. At Pilgrim Nuclear Power Station, the snubber reduction program is a minor
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effort since the total snubber population is only 133. This number includes 78 hydraulics
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and 55 mechanical. Nevenheless, Pilgrim's snubber population is subjected to ISI/IST, as is prescribed by Code. Therefore, the inspector reviewed the ISI/IST snubber surveillance
program, with the following detail:
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Findines a)
ISI/IST Conficuration Controls
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The inspector interviewed the ISI/IST personnel at the Pilgrim Station and reviewed a sample of Problem Reports (prs) generated by the ISI/IST crews. Based on the interviews with ISI/IST personnel and the review of prs, the inspector found a configuration control deficiency consisting of discrepancies between the ISI isometric drawings and the actual piping configuration as installed in the plant. Furthermore, during interviews with the licensee's Quality Assurance Department (QAD), it was found that the ISI isometrics, which provide the basis for ISI component, weld, and support identification, scheduling, and
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examination, have not been updated since 1986. These discrepancies include the number and
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location of the welds and the location of supports and snubbers. For example:
i PR No. 92.0482 reported incorrect location of supports, specifically drawing ISI-I-23-3, Revision E2 incorrectly shows the location of support H-23-1-86.
PR No. 92.0518 reported that ISI-I-10-5R, Rev. E4 did not show welds F329A, F152.A and
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F152B which were added under PDC 85-75.
PR No. 92.0511 reported that weld 14-B-4, Rev. E2 as shown on Isometric ISI-I-14-1 does not exist.
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PR No. 92.0497 reported that weld 6-N4A-ll was not showed correctly on Isometric
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ISI-I-6-1.
Although these prs were properly and timely dispositioned by engineering, the inspector
categorized this as a reaction to the individual support problems and not as a systemic deficiency. The inspector discussed this situation with the licensce's Nuclear Engineering
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Manager who committed to evaluate the extent of ISI drawing discrepancies and to take proper corrective actions. This is an Unresolved Item (No. 93-02-01) pending NRC review of the licensee's corrective action plan.
Conclusion i
The inspector concluded that there may be a systemic deficiency betweea the ISI isometric drawings for piping supports and the actual piping configuration.
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Snubber Control Program During discussions with t,e licensee's mechanical maintenance, ISI and QAD personnel relative to the snubber surveillance program, the inspector established that the criteria
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contained in ASME Section XI Code 1980 Edition, Winter 1980 Addenda, Subsection IWF, Article IWF-5000 for snubber testing (VT-4) was not clearly shown in the ISI/IST snubber
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surveillance procedures. The Technical Specification Section 3.6.G invokes Subsection IWF,
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whereas, Technical Specification 4.6.I provided its own set of criteria for implementation of L
the snubber surveillance program. To resolve these conflicting criteria, a corrective action was implemented to capture both requirements and incorporate them in an effective manner
in the snubber suiveillance procedures.
The inspector reviewed Procedures Nos. 3.M.1-40 " Snubber Maintenance Program,"
Revision 0; 3.M.4-63 " Functional Testing of Mechanical Snubbers," Revision 10; 3.M.4-37
" Hydraulic Snubber Functional Test and Rebuild," Revision 20; and 3.M.4-28 " Visual i'
Examination and Service Life Verification of Safety-Related Snubbers," Revision 22. The inspector verified that all the procedures listed above had the requirements of Technical Specification 3.6.I/4.6.1 and ASME Code Boiler and Pressure Vessel Code Section XI I
Inservice Inspection incorporated.
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Conclusion Based on the review of the snubber surveillance procedures listed above the inspector concluded that the licensee self-imposed corrective action to incorporate the ASME Code,Section XI in these procedures was adequate and complete.
4.0 WALKDOWN OF TIIE SALT SERVICE WATER PIPING REPLACEMENT PROJECT
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Background
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The licensee inspected the Salt Service Water System (SSW) piping during the Refueling
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Outage Number (RFO) #8. The licensee's inspection concluded that the rubber lining of the i
carbon steel piping in the SSW System was near the end of its service life. Continued
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degradation of the lining increases the potential for corrosion of the piping or loss of cooling.
through heat exchanger tube plugging. To prevent these undesirable situations the licensee
has elected to replace the existing buried portion of the Salt Service Water (SSW) Intake i
piping with corrosion resistant titanium piping. This buried portion runs between the Intake l
Structure and the Auxiliary Bay Structures. These replacement activities extend from RFO
- 8, to a mid-cycle mini-outage, and prior to and during RFO #9.
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The engineering scope was divided into several self-contained Plant Design Changes (PDCs).
These PDCs are part of a series of modification packages to replace the buried SSW inlet piping and a portion of the discharge piping between the Intake Structure and the Reactor
Auxiliary Bay. These PDCs are listed and briefly described below:
PDC 91-10A was the first of the series of PDCs that encompass the entire project. This
PDC was implemented on schedule prior to the Mid-Cycle Outage,1992. This PDC consisted of the following: rerouting existing mechanical and electrical interferences running through the area to be excavated during construction of the concrete vault, excavation and shorting of the concrete vault area adjacent to the south wall of the Intake Structure and
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investigation of the use of sheet piles for excavation.
t PDC 91-10B being the second of the series was implemented during the 1992 Mid-Cycle Outage. This PDC consisted of the following: Construction of the concrete vault around the existing SSW piping at the south side of the Intake Structure and construction of a permanent access four by four feet blockout in the intake structure south wall, adjacent to the SSW
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piping penetration.
PDC 91-10C was implemented during the 1992 Mid-Cycle Outage. This PDC outlined the replacement of the two rubber lined carbon steel penetration spools at the Intake Structure south wall with titanium spools.
PDC 91-10D is in process of being implemented. This PDC consists of the following: laying the two proposed new titanium inlet loops in parallel to the existing loops from the Intake
Structure Vault to the Reactor Auxiliary Bay west wall, including portions of the new
titanium discharge loops that share the same excavation.
PDC 91-10E to be implemented during RFO #9, consists of the following: tie in of the two new titanium inlet loops at the Intake Structure Vault and Reactor Auxiliary Bay west wall.
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Findings The inspector walked-down the salt service water project to establish the status. Prior to the
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walkdown, the inspector reviewed composite drawing SKM-91-10D-004, Revision A and pertinent sections of the related PDCs. Presently, the licensee is engaged in the remaining excavation work for the construction of the second concrete vault adjacent to the Auxiliary Reactor Bay Building. During the walkdown, the inspector observed the technical details
encompassing the present status of the project, and determined it is being performed in accordance with the prescribed PDCs.
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Conclusion l
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The inspector verified work is being done in accordance with engineering specifications and i
drawings. He observed good communication between internal and external organizat ons
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engaged in the project.
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5.0 MANAGEMENT MEETINGS
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Licensee management was informed of the scope and purpose of the inspection at the beginning of the inspection. The findings of the inspection were discussed with the licensee management at the January 15,1993 exit meeting. See Attachment 1 for attendance.
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ATTACIIMENT 1 l
Persons Contacted Boston Edison Company W. C. Rothert General Manager, Technical
R. V. Fairbank Nuclear Engineering Manager
l P. Antonopoulos Design Section Manager J. G. Dyckman Civil / Structural Division Manager
- J. S. Roberts Principal Mechanical Engineer R. M. Schifone Quality Control Manager
N. L. Desmond Compliance Division Manager
R. A. Gay Compliance Engineer
J. P. Gerety FS & MC Division Manager
R. S. Sheridan Sr. Quality Assurance Engineer J. L. Jerz Project Manager J. Doyle Sr. Construction Manager U.S. Nuclear Reculatory Commission
'l J. Macdonald Senior Resident Inspector
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- denotes those present at the exit meeting
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