ML20235B096
| ML20235B096 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/30/1987 |
| From: | Withers B WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| WM-87-0176, WM-87-176, NUDOCS 8707080632 | |
| Download: ML20235B096 (8) | |
Text
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h W8LF CREEK NUCLEAR OPERATING CORPORATION Bart D. Withers President and j
Chief Executwo officer June 30, 1987 j
U.S. Nuclear Regulatory Comnission ATTN: Document Control Desk Washington, D.C.
20555 Intter: WM 87-0176
)
Re:
Docket No. 50-482 Subj:
Request for Relief from Certain Post-Repair Testing Requirements Delineated in ASME Section XI Gentlemen:
The purpose of this letter is to transmit three requests for relief from certain post-repair testing requirements delineated in Section XI of the 7merican Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code.
These requests would allow deferment of certain testing requirments until the next refueling outage for cases in which repairs were needed to restore piping with below minimum wall thicknesses to the original design wall thickness. The details of the relief requests have been discussed with j
Mr.
Paul O'Connor and other members of the Nuclear Regulatory Ccmnission
- Staff, Enclosed is a check (No.
000203) for $150.00 application fee required by 10 CPR 170.21.
If you have any questions concerning this matter, please contact me or Mr. O. L. Maynard of my staff.
Very truly yours, Bart D. Withers President and Chief Executive Officer BDW:jad Attachments Enclosure I'
cc:
P0'Connor (2)
RMartin JCummins 4 0 QY, Y,3 8707080632 870630 L
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PDR PO. Box 411/ Burlington, KS 66939 / Phone: (316) 364-8831 An Equal opportunity Employs M FHCVET
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a to MM 87-0176 Page 1 of 1 June 30,1987 Component Component Cooling Water line Line EG-027-HBC-18" (ASME Code Class 3) downstream of Valve EJ-V033.
Description Some areas of the pipe section on line EG-027-HBC-18" downstream of Valve EJ-V033 were found to be below the minimum design wall thickness.
To restore the thickness.to the original design thickness of 0.375",
a carbon steel overlay for a base material repair was welded on the external surfaces of these areas. This repair was completed on June 26, 1987.
Requested Relief Article IWA-7210 of ASME Section XI states, " Replacements shall meet the requirements of the edition of the Construction Code to which the original component or part was constructed...". This pipe section was originally I
constructed to ASME Section III which requires the repair weld to be radiographed if the depth of the cavity exceeds the lesser of 3/8" or 10% of the section thickness.
This requirement was exceeded and a radiographic examination was needed to meet the Code requirements.
A radiographic examination could not be performed with the current operating conditions and therefore temporary relief is being requested from this Code requirement.
Basis for Relief Based on an engineering evaluation, the radiographic examination required by the Code is being deferred.
Wolf Creek Nuclear Operating Corporation is proposing to perform this examination during the next refueling outage. The reason for not performing the radiographic examination was the inability to gain interior access to the piping to perform a proper radiograph during normal plant operations.
Relief to the requirement for performing the radiographic examination may be granted by the Comnission pursuant to paragraph 10 CFR 50. 55a (g) (6) (i) based on determinations that the Code requirement is impractical. The performance of the radiographic examination is impractical in that to open up the pipe for radiography would take extensive time and would require a plant shutdown.
The allowance for the radiograph deferment is based on the expected life of the repaired area and the weld integrity.
Weld layer examinations were performed by the magnetic particle method in accordance with ASME Section
- III, Article ND-2545.
Additionally, on completion of the weld repair an ultrasonic test was performed which showed acceptable thickness of the pipe wall.
These other non-destructive examination methods will insure an acceptable repair was performed until the ' deferred radiograph can be performed.
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Attacluent 2 to W4 87-0176 Page 1 of 2 j
June 30, 1987 Component Pipe Spool 1-EF03-G05/142 (ASME Code Class 3)
Line EF-078-HBC-16"-Essential Service Water line downstream of Valve EF-V058 Description l
Same areas of the pipe section on line EF-0~78-MLl6" downstream of Valve EF-V053 were found to be below the minimum design wall thickness. The piece in particular is the 16" by 24" reducer located downstream of Valve EF-VOS8.
To restore the thickness to the original design pipe thickness a carbon steel overlay for a base matarial repair was welded on the external surface of the areas in concern.
A defect was identified on the final pass of the weld metal overlay.
The defect was a minor pin hole which was too small to accura tely measure ard was visually detected by small amounts of water seepage.
This defect was removed and repaired in accordance with the ASME Code. This repair was comoleted on June 23, 1987 R y ested Relief Article IWA-7210 of ASME Section XI states, " Replacements shall meet the requirements of the edition of the Construction Code to which the original This pipe section was originally ccmponent or part was constructed..
constructed to ASME Section III which requires the repair weld to be radiographed if the depth of the cavity exceeds the lesser of 3/8" or 10% of the section thickness.
This requirement was exceeded ard a radiographic examination was rawded to meet the Code requirements.
A radiographic emnination could not be performed and therefore relief is being requested from this Code requirement.
Due to a "through-wall" defect identified during the weld repair, a system hydrostatic test is required by Article IWA-4400 of ASME Section XI which
- states, "After repairs by welding on the pressure retaining boundary, a
system hydrostatic test shall be performed in accordance with IWA-5000".
The requirement for hydrostatic testing was deemed impractical and was not performed. Therefore, relief is being requested from this Code requirement.
Basis for Relief Ba nd on an engineering evaluation, the radiographic examination required by the Code is being deferred.
Wolf Creek Nuclear Operating Corporation is propocing to perform this examination during the next refueling outage. The reason for not performing the radiographic examination was the inability to gain interior access to the piping to perform a proper radiograph during normal plant operations.
Relief to the requirement for performing the radiographic examination may be granted by the Conmission pursuant to paragraph 10 CFR 50. 55a (g) (6) (i) based on determinations that the Code requirement is impractical. The performance of the radiographic examination is impractical in that to open up the pipe for radiography would take extensive time and would require a plant shutdown.
. to WM 87-0176 Page 2 of 2 June 30, 1987 Based on an engineering evaluation, the hydrostatic test required by Article IWA-4400 of ASME Section XI is being deferred. Wolf Creek Nuclear Operating Corporation is proposing to perform this test during the next refueling outage.
While performing the weld repair, the Action Statement for Technical Specification 3.7.4 was entered due to one train of the Essential Service Water (ESW) system being inoperable. This Action Statement requires that the inoperable train be restored to operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The time required to set up and perform the hydrostatic test would have extended the train outage time to greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and therefore would have required a plant shutdown.
The hydrostatic test was deemed impractical based on the added expense and hardship associated with the transients of shutting down to. MODE 5 (COLD SHUTDOWN) and starting up the unit to allow performance of the test.
The allowance for the radiograph and hydrostatic test deferment is based on the expected life of the repaired area and the weld integrity.
Weld layer examinations were performed by the magnetic particle method in accordance with ASME Section III, Article ND-2545. Additionally, on completion of the weld repair an ultrasonic test was performed which showed acceptable thickness of the pipe wall. These other non-destructive examination methods will insure an acceptable repair was performed until the deferred radiograph and hydrostatic test can be performed.
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,. to NM 87-0176 Page 1 of 1
. June 30,1987 Component Pipe Spool 1-EF-05-S-007/141 (ASME Code Class 3)
Line EF-134-HBC-16" - Essential Service Water line downstream of Valve EF-V090 Description Pipe Spool 1-EF-05-S-007/141 in Essential Service Water (ESW) line EF-134-HBC-16" was found to have areas below the minimum design wall thickness.
The internal surface was eroded as a result of cavitation and a through wall defect was detected.
To restore the thickness to the original design thickness, a base metal repair was performed on the internal surface of these areas in compliance with the ASME Code. This repair was performed and completed during the first refueling outage.
Relief Requested Due to a "through-wall" defect identified during the weld repair, a system hydrostatic test is required by Article IWA-4400 of ASME Section XI which
- states, "After repairs by welding on the pressure retaining boundary, a system hydrostatic test shall be performed in accordance with IWA-5000".
For ASME Class 3 components IWA-5000 refers to the test conditions specified in Article IWD-5000 which requires, in part, that the system hydrostatic test pressure be at least 1.10 times the system pressure for systems with a design temperature of 200 0 F or less.
Due to a problem with the hydrostatic testing equipment, which was discovered after completion of all work, the system hydrostatic test pressure was determined'to be less than 1.10 times the design system pressure.
Therefore, temporary relief from this Code requirement is being requested.
Basis for Relief Based on an engineering evaluation, the hydrostatic test required by Article IWA-4400 of ASME Section XI is being deferred. Wolf Creek Nuclear Operating Corporation is proposing to perform this test during the next refueling outage.
Relief to the requirement for performing the hydrostatic test may be granted by the Commission pursuant to paragraph 10 CFR 50. 55a (g) (6) (i) based on determinations that the Code requirement is impractical.
Performance of the hydrostatic test would require the plant to be in MODE 5 (COLD SHUTDOWN).
Therefore, this test is deemed impractical based on the added expense and hardship associated with the transients of shutting down and starting up the unit to perform the hydrostatic test.
'Ihe allowance for the hydrostatic test deferment is based on an acceptable weld repair which was performed in accordance with the Code.
Examinations were performed by the magnetic particle method la accordance with ASME Section III, Article ND-2545.
The repair was also radiographed in accordance with ASME Section III, Article ND-5000.
These non-destrudtive examinations met all applicable acceptance criteria and insured an acceptable repair was performed until the hydrostatic test can be performed again.
Although the original hydrostatic test did not meet the required test pressure, the hydrostatic test was performed at a pressure considerably higher than normal system operating pressure and no problems were identified.