ML20006D906
| ML20006D906 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/07/1990 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-008, IEB-88-8, NUDOCS 9002150239 | |
| Download: ML20006D906 (4) | |
Text
1 I
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alley Power Station Stuppingport. PA 1607164 1
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February 7, 1990 1
1 U. S.-Nuclear Regulatory Commission
' Attn:
Document Control Desk Washington, DC 20555 i
Reference:
Beaver Valley Power Station, Unit No. 1 j
Docket No. 50-334, License No. DRP-66 NRC Bulletin 88-08 i
l Gentlemen:
Attached is a
follow-up report for NRC Bulletin 88-08,
" Thermal Stresses in Piping Connected to Reactor Coolant Systems".
This report is required by Reporting Requirement 2 of the Bulletin and provides the results of actions taken at Beaver Valley. Unit i during the seventh refueling outage.
l
.If there are any questions concerning this matter, please contact my office.
t Very truly yours, a
2h.
. D. Sieber Vice President Nuclear Group Attachment cc:
Mr. J.
Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator Mr. P. Tam, Sr. Project Manager Director, Safety Evaluation & Control (VEPCO) l M
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t COMMONWEALTH OF PENNSYLVANIA)
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COUNTY OF BEAVER
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On this day of L Ml/8221-
- 1990, before me, Aldi/
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a Notary Public n and for said Commonwealth and county, personally appeared J.
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Sieber, who being duly sworn, deposed, and said that (1) he is Vice President - Nuclear of Duquesne Light, (2) he is duly authorized to execute and file the f
foregoing Submittal on behalf of said Company, and (3) the statements-set' forth in the Submittal are true and correct to the best of his
- knowledge, information and belief.
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DUQUESNE LICHT COMPANY Nuclear Group Beaver Valley Power Station Unit 1 Attachment 1
Follow-uo ReDort for NRC Bulletin 88-08 Action Items 2 and 3 I
For any unisolable sections of piping connected to the RCS that may have been subjected to excessive thermal
- stresses, examine nondestructively the
- welds, heat-affected zones and high stress locations, including geometric discontinuation, in that piping to provide assurance that there are no existing flaws.
Plan and implement a
program to provide continuing assurance that unisoluble sections of all piping connected to the RCS will not be subjected to combined cyclic and static thermal and other stresses that could cause fatigue failure during the remaining life of the unit.
This assurance may be provided by (1) redesigning and modifying these sections of piping to withstand combined stresses caused by various loads including temporal and spatial distributions of temperature resulting from leakage across valve
- seats, (2) instrumenting this piping to detect adverse temperature distributions and establishing appropriate limits on temperature distributions, or (3) providing means for ensuring that pressure upstream from block valves which might leak is monitored and does not exceed RCS pressure.
Response
In our September 20, 1988 response to Action Item 1 we identified the following Beaver Valley Unit 1
(BV-1) piping lines which could be subjected to stresses from thermal stratification or temperature oscillations assuming that all normally closed valves would leak by.
Beaver Vallev Unit 1 Pipina Lines 6"-SI-20-1502-Q1 SAFETY INJECTION TO "A" HOT LEG 6"-SI-72-1502-Q1 SAFETY INJECTION TO "A"
COLD LEG 6"-SI-29-1502-Q1 SAFETY INJECTION TO "B" HOT LEG 6"-SI-73-1502-Q1 SAFETY INJECTION TO "B"
COLD LEG 6"-SI-30-1502-Q1 SAFETY INJECTION TO "C" HOT LEG 6"-SI-74-15-2-Q1 SAFETY INJECTION TO "C"
COLD LEG 2"-CH-140-1503-Q1 CHARGING FILL TO "A" LOOP 2"-CH-141-1503-Q1 CHARGING FILL TO "B" LOOP 2"-CH-142-1503-Q1 CHARGING FILL TO "C" LOOP 2"-CH-23-1502-Q1 NORMAL CHARGING TO PRESSURIZER SPRAY LINE In addition to the above lines, an additional location on the BV-1 Residual Heat Removal System was identified for examination and instrumentation.
This line, 14"-RH-1-1502-Q1, RHR suction to "A" hot leg was identified based on our review of the Genkai Plant RHR suction line cracking problem, which was the subject of NRC Bulletin 88-08, Supplement 3.
- Atthchment Follow-up Report for NRC Bulletin 88-08 Page 2 During the BV-1 seventh refueling
- outage, these lines were nondestructively examined at selected locations which included welds, heat-affected zones and high stress locations, including geometric discontinuation.
The nondestructive examination locations and technique took into account the guidance provided by Bulletin 88-08, Supplements 1
and 2.
The ultrasonic examinations of the selected locations covered the fitting, fitting-to-pipe or fitting-to-fitting welds and a
minimum of one (1) inch of adjacent base material, and was covered to the maximum extent possible as permitted by accessibility and component geometry.
Ultrasonic scans were conducted at beam angles of 45 and 60 degrees.
Liquid penetrant examinations supplemented the ultrasonic examinations.
No rejectable indications were found during the ultrasonic examinations.
Two (2) rejectable indications were found during the liquid penetrant examinations, both indications were on a fitting on the charging fill to "B"
loop line.
This fitting was reexamined following surface conditioning and the result of the reexamination was satisfactory.
During the seventh refueling
- outage, the above lines were instrumented with thermocouples at strategic locations.
Data collection began at startup from the seventh refueling outage and is continuing.
The recorded data has been evaluated against established acceptance criteria and has shown that:
1)
Stratification does exist in the majority of the lines.
However stratification
- itself, as in this case, is constant and has a negligible effect on stresses in the line.
2)
The temperature distributions recorded in the pipes do not fluctuate to any major degree that would cause additional fatigue cycling.
Monitoring of these lines will continue during the eighth fuel cycle at BV-1.
If the stratification conditions exceed the acceptance criteria, appropriate corrective action will be taken.
We will use the results of the temperature monitoring program in our consideration of a
long-term solution to Action Item 3
of the Bulletin.
We will provide a letter describing our plans to resolve this-concern by June 30, 1990.
Temperature monitoring will continue until a long term solution is implemented.