ML20050A822
| ML20050A822 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/30/1982 |
| From: | Padovan M Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20050A808 | List: |
| References | |
| NUDOCS 8204020304 | |
| Download: ML20050A822 (7) | |
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UNITED STATES
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WASHINGTON. D C. 20555 e
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March 30,1982 LICENSEES: Babcock & Wilcox Licensees & B&W Representatives
SUBJECT:
SUMilARY OF THE MARCH 16, 1982 MEETING WITH B&W LICENSEES AND REPRESENTATIVES CONCERNING HPI N0ZZLE CRACKING On March 16, 1982, a meeting was held at the NRC offices in Bethesda, MD to discuss make-up nozzle cracking problems discovered at B&W plants.
Representatives from the NRC, B&W licensees, B&W and the CE and B&W Regulatory This meeting Response Groups (RRGs) attended, as shown in Enclosure 1.
was a follow-up to the meeting held on March 8,1982, regarding continued operation of plants that had not yet inspected for cracks in the make-up nozzles, (i.e., Arkansas Nuclear One, Unit No.1 ( ANO-1) and Rancho Seco). The purpose of the meeting was to provide an opportunity for the B&W RRG to present up-to-date results from inspections and analyses of the make-up nozzles on the Crystal River 3 and the Oconee plants; and to relate these findings to licensee recomendations for continued operation of ANO-1 and Rancho Seco Jntil the shutdowns At the meeting, the B&W proposed for nozzle inspection at these plants.
RRG also updated the staff regarding licensee's actions to 1) gather and analyze experimental data on the nozzles and 2) institute long term programs to further evaluate the cracking problem. The RRG proposed meeting agenda is provided in Enclosure 2.
Mr. J. Mattimoe, Chairman of the B&W RRG, provided an introduction and overall description of the material to be presented to the staff.
Plant specific presentations were then given as follows.
Crystal River 3 (CR-3)- presented by Mr. L. Tittle - Florida Power Corp. (FPC)
Thermocouples (TCs), accelerometers and strain guages were installed on the CR-3 make-up line to monitor pipe wall temperature variations, pipe movements and strain on the piping. Data was gathered up to a reactor power of 100% with the make-up flow reduced to values as low as 1.5 gpm.
No significant T/C variations were noted as a function of make-up flow; but the 0.D. T/C mounting does not accurately reflect temperature variations at the I.D.
of the make-up nozzle.
It was noted that the present make-up line configuration at CR-3, containing the monitoring instrumentation, is now different than the configuration existing at the time the nozzle crack:ng occurred. Thus, data obtained might not reflect mechanisms that contributed to the cracking.
At CR-3, plant procedures have been re-verified to assure that a 15 gpm Additionally, an make-up bypass flow is maintained at all times.
The augmented ISI program is being recomended to FPC management.
augmented program would require UT & RT exams of the nozzle areas during the first cold shutdown. During subsequent outages, visual, UT, PT, and RT (or push-pull) examinations would occur.
0204020304 820331 PDR ADOCK 05000312 C
. In the long term, FPC is considering establishing an internal organization, consisting of engineers, operators and consultants, to study the cracking problem. A list of possible, long term actions has been developed by B&W and is under consideration by the CR-3 staff.
All nozzle repairs have been completed at CR-3 and the unit has returned to power operation.
Oconee-presented by Neal Rutherford - Duke Power Company All make-up and HPI nozzles on all Oconee units have been RT & UT ins pected. The results of the inspections are shown in Enclosure 3.
Repairs are currently underway on the Oconee 3 unit. Repairs on the Oconee 2 unit will be completed prior to startup. At Oconee 2 and 3, each plant was found to have cracks in one make-up nozzle that had a loose tie-mal sleeve. There were no nozcle cracking problems on Unit 1 Davis-Besse-presented by R. P. Crouse Toledo Edison Company Radiographs of the 4 nozzles indicated that all thermal sleeves are in the correct position, and all weld " buttons" accessible for RT examination were found to be in place. Three of four thermal sleeves had been hard rolled when found loose prior to initial startup of the plant.
The Davis-Besse unit is presently shutdown for refueling, and all nozzles will be UT inspected prior to restart.
Threc Mile Island (TMI-1)-presented by Don Croneberger - GPU Nuclear Visual, external P.T. and R.T. examinations were performed on the make-up nozzle. No unsatisfactory indications were found. The NRC staff, however, was concerned that the TMI examination procedures were not compared with the CR-3 and Oconee techniques. Cracks could possibly exist without GPU being able to identify them.
Piping configuration changes are being evaluated by GPU, since the make-up line check valve is welded directly to the inconel safe-ends (similar to the previous CR-3 configuration).
The TMI-l unit is presently shutdown pending steam generator repairs and a restart decision by the Commission.
Arkansas Unit One ( ANO-1)- presented by John Griffin - Arkansas Power & Light Co.
ANO-1 is presently operating at power. On March 26, 1982, the unit will be shutdown for a four week outage.
All four nozzles will be examined by RT and UT, using the same procedures and methodology used at CR-3 and Oconee. The results of the examinations are expected to be available during the first week in April.
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B&W Owner's Group - presented by Patsy Baynard - Florida Power Corp.
X task force is being established to evaluate the cracking problem and detemine what long term actions are necessary. The feasibility and benefit of installing instrumentation internal to the make-up and HPI lines will be investigated. Any plant specific actions that are to be taken as a result of the Owner's Group evaluations will be communicated to the NRC through the PM rather than via the Owner's Group.
A program plan, with a primary mission of determining the cause of the nozzle cracking, will be produced in a few weeks.
Rancho Seco - presented by John Mattimoe - Sacramento Municipal Utility District (Sm E18il has completed an analysis of the Rancho Seco make-up line configuration (safe e :d, 90 elbow, and 21" piping run to the check valve) and believes that nozzle cracking would result in a leak before occurrence of a break.
Additional justification for continued reactor operation until the Septer.ber refueling outage includes:
- 1) Rancho Seco has always had a high minimum make-up flow to minimize thermal cycling.
- 2) The piping is in accordance with the B&W design (more than 4" of piping between the safe end and check valve) and it. Wilar to ANO 1 which will be inspected soon.
3)
Plant operators have been indoctrinated in handling small break loss of coolant events that would occur for postulated no.:zle breaks.
A review of plant records did not show a previous record of loose themal sleeves. Rancho Seco is presently operating at power.
Following a NRC staff caucus, the staff agreed that the March 26, 1982 inspection shutdown as described for ANO-l was acceptatae. However, the staff recommended a much earlier shutdown for Rancho Seco than that proposed by the licensee.
SMUD agreed to shutdown Rancho Seco for the inspection before April 9,1982 which was acceptable to the staff. In its letter dated March 19, 1982, SMUD confirmed its commitment to radiographic and ultrasonic inspections of all four high pressure injection nozzles by April 9,1982.
C5e Mark L. Padovan, Project Manager Operating Reactors Branch #4 Division of Licensing
MAKE-UP N0ZZLE CRACKING FifCH 16,1982 MEETING NRC - BETHESDA Name Affiliation Syd Miner NRC/DL John Stolz NRC/DL Tom Novak NRC/DL John M. Griffin AP&L Don Rueter AP&L Patsy Baynard FPC Larry Tittle FPC Mark Padovan NRC/DL N~ d or.omos NRC/ Region II Phil Wagner NRC/DL John Mattimoe SMUD William Collins NRC/IE:HQ Ruby Straub B&W D. Guilbert B &W J. D. Carl ton B&W J. J. Sheppard CP&L/WOG Neal Rutherford Duke Power Co.
John Norris Duke Power Co.
R. M. Douglass BG&E -CE-RRG R. Ganthner B &W Albert DeAgazio NRC/DL Don Croneberger GPU Nuclear Harvey Canter Rancho Seco RI NRC-V I
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-2 Name Affiliation C. T. Daf t Toledo Edison Co.
R. P. Crouse Toledo Edison Co.
Robert Peters Toledo Edison Co.
Warren Hazelton NRC/MTEB R. W. Klecker NRC/MTEB E. Igue ACRS/NRC Hal Ornstein NRC/AE0D Earl Brown NRC/AE0D Guy Vissing NRC/DL R. Purple NRC/DL D. Eisenhut NRC/DL W. Johnston NRC/DE C. Serpan NRC/RES/DET Ed Jordan NRC/IE R. Vollmer NRC/DE T. Ippolito NRC/0RAB l
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PROPOSED AGENDA INTRODUCTION (MATTIM0E)
PURPOSE:
FPC/CR PROGRESS, WHAT OWNERS GROUP WILL D0.
OTHER UTILITY PROGRESS &
UTILITI SPECIFIC JUSTIFICATION FOR 4
CONTINUED OPERATION CR PROGRESS (TITTLE)
TESTING UPDATE LONG TERM EFFORT OTHER DEVELOPMENTS OTHER UTillTY PROGRESS OCONEE DAVID BESSE TMI-1 AND OWNERS GROUP (BAYNARD)
COMMIT TO COMMUNICATIONS-B8W PROPOSED LONG TERM ACTION LIST:
o THE " NICE TO KNOW"
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o PLANT SPECIFIC INFORMATION o
GENERIC INFORMATION UTILITY PRESENTATIONS ON WHY THEIR PLANTS ARE SAFE FOR CONTINUED OPERATION CONCLUSION (MATTIM0E)
RESTATE WHAT WE HAVE TOLD THEM IDENTIFY WHERE WE G0 FROM HERE
OCONEE N1TCLEAR STATTON SFATUS OF llPI N0Z7.1.ES SAFE END/ PIPE PIPE N0ZZLE TilERMAL SLEEVE CFACK RADI(X:RAPil INSIDE SPECIAL lAl OK No Yes No Yes i
1A2 OK No Yes Yes Yes i
IBl OK No Yes No Yes 1B2 OK No Yes No Yes 2A1 OK No Yes No Yes Yes(
Yes No (6)
Yes 2A2 Loose 2B1 Loose No Yes No (6)
Yes Cracked (5)
No Yes No (6)
Yes 2B2 3Al OK No Yes No Yes Ys(l)
)
Yes(3)
Yes Yes 3A2 Loose 3B1 Loose No Yes No (6)
Yes 3B2 OK No Yes No Yes NOTES:
(1) After PT (2) 6 longitudinal cracks; 1" - 2" length; started in safe end and runs into piping distributed 360 around, g
S No depth information.
V a
u, (3)
>12 longitudinal cracks, %6" long; started in safe end and runs into piping; distributed 360 around; y
1 crack at 20% of wall thickness, other less.
w (4) Weld buttons missing, gap in rolled area %1/16" - 1/8".
I (5) Cracked in rolled area.
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