ML20206D097
| ML20206D097 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 04/02/1987 |
| From: | Kowalski S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 198, NUDOCS 8704130243 | |
| Download: ML20206D097 (4) | |
Text
.
2876032230 s-PHILAD ELPHI A ELECTRIC - COM PANY
?3O1 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 (215)841-4502 vic t-P n ssID E NT e.....................
Dr. Thomas E. Murley, Administrator U.S. Nuclear Regulatory Commission Region I Attention: Document Control Desk Washington, DC 20555
Subject:
Significant Deficiency Report No. 198
)
CADD Conversion of P&ID's and QAD's i
Limerick Generating Station, Unit 2 NRC Construction Permit No. CPPR-107 l
References:
a)
Telecon, P. K. Pavlides, PECo to H. Williams, USNRC dated 3/3/87 b) 10CFR Part 21 Report, J. W. Gallagher, PECo to T. E. Murley, USNRC dated 3/16/87 File:
QUAL 2-10-2 SDR No. 198
Dear Dr. Murley:
In compliance with 10CFR50.55(e), we are submitting our final Significant Deficiency Report concerning the subject CAED P&ID's and QAD's.
In the l
reference a) telecon we reported this item as potentially reportable.
Further review noted it to be reportable under 10CFR50.55(e).
A 10CFR Part 21 Report (reference b) on this subject was previously submitted for Limerick Unit 1.
If further information is required, please do not hesitate to contact us.
j Sincerely,
/
/~l JAG /aag/03188701 Attachment Copy to: Addressee Director of Inspection and Enforcement E. M. Kelly, LGS Senior Resident Site Inspector - Unit 1 R. Gramm, LGS Senior Resident Site Inspector
- Unit 2 See Attached Service List fh 3
41
676032230 Significant Deficiency Report - SDR No. 198 CADD Ccoversion of PSIDs and QADs Limerick Generating Station Unit 2 NRC Construction Permit No. CPPR-107 Description of Deficiency Beginning in July 1986 and for approxfrately three weeks, Bechtel Western Power Corporation (Bechtel) began issuing to Philadelphia' Electric Company (PECo) ar.d Bechtel construction personnel Piping and Instrunentation Diagrams (PSID) which had been generated via Computer Aided Design and Drafting (CADD). These CADD-generated PSID's were requested by PECo in order to unitize (spilt Unit 1 and Ccmnon Information from Unit 2 Information) and to reduce the density of the information
- per sheet (spread out the system PSID information over several sheets).
During this revision process, a significant nurber of discrepancies were introduced into the PSIDs for Unit 2.
As the result of hunan error on the part of Bechtel Western Power Corporation personnel performing the review these discrepancies were not discovered prior to the issuance of the CADD-generated PSIDs. The discrepancies that were introduced into the PSIDs that show safety-related systems and components were also introduced into the Quality Assurance Diagrams (QAD) which are based on the PSIDs and are used to identify boundaries of safety related equipment and systems. Discrepancies unique to the QADs were also identifled.
Analysis of Safety implication _s__
Review of all 116 Unit 2 CADD-generated PSID sheets resulted in Identification of approximately 850 discrepancies. The following tabulation shows the general type of discrepancy and its cercentage of occurrence:
Category Percentage 1.
Line No., Valve No., or 34.5%
Instrunent No. discrepancy 2.
Clarifications (e.g. relocate note 10%
with proper equipment) 3.
Transfer coordinate mismatch 22%
4.
Title block or fonnat discrepancy 27.5%
5.
Pipe class or material Information 6%
discrepancy 100%
s
2676032230 It is highly unlikely that any of the discrepancies, even if uncorrected, would have any impact on Unit 2 construction since the base design, including original but yet unissued design drawings, was ccmplete prior to issuance of the CADD PSIDs and QADs. Subtler design and installation drawings should not be affected by discrepancies in the CADD P&lDs and QADs. PSID or QAD changes cause changes to these drawings only when pre-approved design docunents (i.e. Design Change Notice, Fleid Change Request) are Identified as being incorporated into the PSID or QAD. As will be discussed in the next section, however, l
corrective actions are under way to verify that construction has not been or will not be affected.
It is also unilkely that these discrepancies could have gone uncorrected through the extensive as-built verification, pre-operational and startup programs and affected Unit 2 operation. The as-built verification program includes walkdown of the installed system while ccmparing the actual conditions to design drawings including the PGID and corresponding piping Isometrics. Differences would be identified and resolved. Generation of the Unit 2 pre-operational and startup test procedures includes conparison with the corresponding Unit 1 procedures. This, and the actual testing itself would also allow P&ID problems to be identified and corrected.
If however, discrepancies migrated through this process, the potential inpact would depend on the specific discrepancy.
Our review of the above discrepancies for future operational impact Indicates that the most potentially serious would be those involving incorrect valve nuiters. An incorrect valve nurber by itself has a low potential for impact on plant operations, however, a PSID showing two or more valves with their nurbers transposed has the potential for much greater impcct.
If these CADD-generated PSIDs were used to prepare new or revised procedures and blocking sequences, a potential scenarlo, although unlikely, is that a blocking sequence or a procedure with the valve nurbers incorrectly designated due to transposition discrepancies could have been written or revised.
Inadvertent removal of one safety system or train from service while at the same time another redundant safety system or train could have been out of service may have resulted.
If this situation had occurred, and had not been detected by operations personnel, it could have resulted l
In a violation of the Technical Specifications' Limiting Conditions of Operations.
Corrective Actions A complete re-check of the CADD-generated PSIDs has been caTpleted. The corrected PSIDs were completely re-issued by February 24, 1987.
The QADs have been reviewed to correct the discrepancies noted on the PSIDs. The CADD-generated QADs have also been reviewed against the latest hand-drawn version so that necessary corrections to the safety-related boundarles could be made. The QADs are currently in the process of being re-issued.
2676032230.
An effort to review subtler documents that could have been prepared or revised based on the CADD-generated PCIDs issued during July 1986 and the subsequently issued QADs is under way. This review includes revised or new Construction Work Packages, Quality Control Inspection Records, startup procedures and procurement doctments for safety-related components.
In addition, to ensure the accuracy of the corrected CADD drawings, the Mechanical Engineering Division of the PECo Engineering and Research Department (ESR) will review and approve drawing changes incorporated since the hand-drawn versions. The PECo ESR Engineering Design Division will also perfonn a line-by-line review of approximately 10% of the revised sheets against the hand-drawn versions.
Since CADD conversion of the Limerick PSIDs and QADs is expected to be a one-time effort, this situation should not recur. However, resolution of several findings issued by the PECo ESR Quality Assurance Division is expected to prescribe corrective actions to prevent similar problems should CADD conversion of these or other drawings occur in the future.
All corrective actions are expected to be complete prior to August 1, 1987.
JAG /cb/03188702
.