ML20070V803
| ML20070V803 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/10/1983 |
| From: | Hall D ILLINOIS POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, U-10027, NUDOCS 8302180127 | |
| Download: ML20070V803 (4) | |
Text
r 1605-L ILLINOIS POWER OOMPANY U-10027 CLINTON POWER STATION. P.O. box 678. CUNTON. ILUNOIS 61727 February 10, 1983 Docket No. 50-461 Mr. James G. Keppler Regional Administrator Region III U. S. Nuclear Regularcry Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Deficiency 82-10 10 CFR50. 55 (e)
Safety Related Piping Minimum Wall Violations
Dear Mr. Keppler:
On October 7, 1982, Illinois Power verbally notified Mr. P.
Pelke, NRC Region III of a potential reportable deficiency per 10CFR50.55(e) concerning possible mir.imum wall violations for safety related piping.
This initial nstification was followed by one (1) interim report (letter U-10009, D. P. Hall to J. G.
Keppler dated November 12, 1982, 1605-L) where it was stated that approximately six (6) months would be required to complete our investigation of this matter.
This letter presents an update of our investigation and status of corrective action, and is submitted as an interim report on this reportable deficiency.
STATEMENT OF REPORTABLE DEFICIENCY Two (2) cases have been identified where piping with less than minimum allowable pipe wall thickness was installed in ASME class 2 piping systems, as follows:
a.)
In the Residual Heat Removal (RHR) system, line number 1RH03BB12, pipe of 0.375 inch (nominal) wall thickness was installed; design analysis dictates the use of pipe of 0.843 inch (nominal, schedule 100) wall thickness.
b.)
In the Low Pressure Core Spray (LP) system, line number 1LP21A4 and 1LP21B4, pipe of 0.237 inch (nominal, schedule 40) wall thickness was installed; design analysis dictates the use of pipe of 0.337 inch (nominal, schedule 80) wall thickness.
FEB 141983 8302180127 830210 PDR ADOCK 05000461 S
PDR yy
J. G. Kcppler Page 2 of 4 This condition has been determined to be a significant deficiency in final design and construction and is therefore reportable under 10CFR50.55(e).
BACKGROUND / INVESTIGATION RESULTS As part of the preservice inspection program, certain welds were being ultrasonically examined for weld thickness by Baldwin Associates (Illinois Power Contractor).
During these examina-tions, it was found that the wall thickness of the pipe at several welds in the RHR system was less than required by applicable piping installation documentation.
A Nonconformance Report (NCR 7618) was written to document this problem.
In the process of evaluating this NCR, it was determined that the measured wall thickness (0.305 inch) at the weld was not only less than that specified in the installation documents (0.375 inch), but the information in the installation documents did not correspond to the design information (0.406 inch) supplied by Sargent & Lundy (CPS Architect / Engineer).
Further investigation into this matter showed that the various design documents supplied by Sargent & Lundy to the Piping Fabricator (Southwest Fabricating and Welding) also contained inconsistencies.
Accurate design information for this pipeline requires a nominal wall thickness of 0.843 inch (Schedule 100).
Investigation of this matter found that several errors led to this occurrence.
When the pipe was detailed and fabricated, the Sargent & Lundy piping line 14.st correctly specified a wall thickness of schedule 100 (0.843 inch nominal) for pipeline 1RH03BB12.
However, the associated Sargent & Lundy piping and instrument diagram (P&ID)
(M05-1075), and the single line piping drawing (M06-1075) for this pipe erroneously specified a wall thickness of schedule 40 (0.406 inch nominal).
The fabrication icometric drawing (RH-21) and spool piece detail drawing produced by Southwest Fabricating and Welding compounded the error by erroneously specifying standard wall thickness for this line (0.375 inch r.ominal).
As a result, the pipe was fabricated and installed as standard wall pipe, in accordance with the incorrect isometric and spool piece detail drawinga.
In reviewing the history of the design of this pipeline, it was determined that the original design was properly performed and all design documents consistent.
However, in late 1978 and early 1979, new loads evaluation had proceeded to the point that suppression jool swell conditions developed additional, external, loads on the pipe that were not considered in the original design basis.
The resulting re-analysis required that pipe wall thickness for certain lines be increased.
This required wall thickness increase uas not properly transferred to all affected design documents.
J. G. Keppler Page 3 of 4 1
Further investigation of other piping affected by this redesign has shown that one (1) additional system, line numbers lLP21A4 and 1LP21B4, has wall thickness problems.
In the case of line numbers lLP21A4 and 1LP21B4, the piping line list and P&ID (H05-1073) specified schedule 80 (0.337 inch nominal wall thick-ness), but the piping drawing (M06-1073) specified schedule 40 (0.237 inch nominal wall thickness), and the isometric drawing (LP-5) shows schedule 40.
Schedule 40 pipe was subsequently installed.
Two (2) similar cases of this problem were identified with line numbers 1CC57C4 and 1CY28B6.
In these two cases, the fabricator's isometric drawings specified schedule 40 pipe, but i
the associated design' drawings (M06's) specified schedule 80 for portions of the lines.
All schedule 40 pipe was subsequently provided to Baldwin Associates for installation.
However, this error was discovered in early 1981 by Baldwin Associates, and the correct pipe material was installed.
CORRECTIVE ACTION (INTERIM REPORT)
Illinois Power is taking the following steps to determine the scope of the deficiency, correct identified deficiencies, and prevent recurrence:
).
Sargent & Lundy is reviewing their design information for safety-related p; ping subject to external loading to ensure that the design documents are consistent and adequate.
This review is substantially complete and has thus far identified no additional inconsistencies other than those previously noted in this report.
2.
Sargent & Lundy is reviewing and statusing safety related, augmented D, and Fire Protection related process piping isometric drawings to ensure, among o ther things, that the correct wall thickness has been specified for fabrication and installation.
This review also includes comparison of various S&L design documents for consistency.
Through the end of January,
- 1983, 637 drawings had been reviewed.
No additional l
cases of wall thickness violations have been identified, although other minor problems have been identified and require correction (e.g. addition of l
flow arrows, minor dimensional inconsistencies, missing i
notes, etc.).
The large and small bore process piping isometric drawing review is scheduled for completion by April 1, 1983.
3.
Upon completion of No. 2 above, remedial action for the identified design and fabrication document inconsis-tencies (and associated installed piping) will be evaluated and determined.
Potential actions could require external protection of piping, additional l
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J. G. Keppler Page 4 of 4 hangers, engineering analysis of the as-installed piping, or replacement of the pipe.
It is expected that the evaluation will be completed and a plan for remedial action for the three (3) pipelines (1RH03BB12, ILP21A4, ILP21B4) developed by March 1, 1983.
Evaluation of any additional deficiencies that may result from the isometric drawing and document review will be performed by June 1,1983.
4.
Illinois Power has formulated a plan to increase its review activities of Sargent & Lundy large bore pipe design.
This plan,, esently undergoing Illinois Power management review and approval, calls for detailed technical reviews of selected piping subsystems on an on-going basis.
It is expected that this plan will be approved for use mnd implemented during February, 1983.
Completion of the first subsystem review is currently scheduled for the middle of March, 1983.
SAFETY IMPLICATION / SIGNIFICANCE The pipelines in question are subject to pool swell impact which produces significant external loads on the piping.
Failure of the RHR piping could potentially result in less emergency core cooling flow to the reactor than required by design.
Failure of the LP piping in question could result in degraded containment integrity.
Although additional investigation and analysis are necessary to determine the scope of the deficiency, evaluate identified problems, and determine necessary corrective actions to correct this deficiency and to prevent recurrence, this deficiency does present an adverse impact on the safety of operations of CPS, and is therefore considered reportable under 10CFR50.55(e).
It is anticipated that our investigation and analysis of this reportable deficiency will be completed by June 15, 1983, at which time a final report on this matter can be provided.
We trust that this interin letter provides sufficient information to perform a general assessment of this deficiency, and overall approach to resolution of the problem.
S' el
- yours,
. Hall Vice President cc:
Director, Office of I&E, US NRC, Washington, DC 20555 NRC Resident Inspector Illinois Office of Nuclear Safety Manager-Quality Assurance