ML19330B993
| ML19330B993 | |
| Person / Time | |
|---|---|
| Issue date: | 04/09/1980 |
| From: | Carroll D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wright G ILLINOIS, STATE OF |
| References | |
| NUDOCS 8008070377 | |
| Download: ML19330B993 (2) | |
Text
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d'pa rtnq'o UNITED STATES NUCLEAR REGULATORY COMMISSION
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799 ROOSEVELT ROAD GLEN ELLYN, ILLINOIS 60137
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o APR 9 1880 Itate of Illinois Department of Public Health ATTN:
Mr. Gary N. Wright, Chief Division of Nuclear Safety 535 West Jefforson Street Springfield, IL 52761 f
Gentlemen:
The enclosed IE Bulletin No. 80-07 titled "BWR Jet Pump Assembly Failure" was sent to the following licensees on April 7, 1980.
Cincinnati Gas & Electric Company Zimmer (50-358)
Cleveland Electric Ill. Company Perry 1, 2 (50-440, 50-441)
Commonwealth Edison Company Dresden 1, 2, 3 (50-237, 50-249)
Quad-Cities 1, 2 (50-254, 50-265)
LaSalle 1, 2 (50-373, 50-374)
Consumers Power Company Big Rock Point (50-155)
Dairyland Power Cooperative LACBWR (50-409)
Illinois Power Company Clinton 1, 2 (50-461, 50-462)
Iowa Electric Light & Power Company Duane Arnold (50-331) 1 i
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State of Illinois 0 Forthern Indiana Public Service Company Bailly (50-367)
Northern States Power Company Monticello (50-263)
Sincerely, 1
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orothy E.
arroll, Acting Chi Administr tive Branch
Enclosure:
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Mr. D. W. Kane,
Sargent & Lundy Central Files Reproduction Unit NRC 20b Local PDR NSIC TIC i
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UNITED STATES 8002280648 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 April 4, 1980 i
IE Bulletin No. 80-07 BWR JET P' MP ASSEMBLY FAILURE J
Description of Circumstances:
On February 2,1980, Commonwealth Edison Company (CECO) reported that a jet pump failed in Dresden Unit 3 while operating at about 67 percent of full power in a coastdown mode to a refueling shutdown.
Observed changes in plant parameters during the event indicated an individual jet pump failure had occurred.
In accordance with T.S., an orderly plant shutdown was begun to bring the unit to cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The plant parameter changes reported by the licensee were (1) generator electrical output decreased from 539 to 511 MW electrical, (2) core thermal power decreased as indicated by decreased APRM readings and steam flow tg the turbine, (3) indicated total core flow increased from 97.6 to 104.7 x 10 lb./hr., (4) core plate differential pressure decreased from 16.1 to }3.8 psid., and (5) B recirculation loop flow increased gpm while A recirculation loop flow remained at 49 x 10{ rom 49 to 54 x 10 gpm. These changes were readily observed by the operator in the control room and it was postulated that a jet pump had failed.
Individual jet pump readings were taken, the jet pump operability surveillance was performed, and an apparent failure of jet pump No. 13 was determined.
Following vessel head removal and defueling, TV camera and visual inspections of the jet pumps and vessel annulus revealed the hold-down beam assembly of the suspect jet pump had broken across its ligament sections at the mean diameter of the bcit thread area.
Failure of the beam assembly resulted in pump decoupling at the diffuser connection.
Subsequent insitu ultrasonic examination of all other jet pump hold-down beams, using a special UT technique developed by General Electric revealed ultrasonic indications of cracking at the same location in 6 of the remaining 19 beams examined.
Initial estimates of crack depth ranged from 6 to 20 mils.
A sketch of the typical jet pump assembly is shown in figures 1 and 2.
On March 15-16, 1980, insitu ultrasonic examination was performed on all 20 jet pump hold-down beam assemblies at Quad Cities 2 (currently shutdown for refueling).
One beam was found to contain a crack indication estimated to be in excess of 100 mils depth in the same location on the beam as found at Dresden.
On March 28, 1980, Boston Edison reported that ultrasonic examination revealed crack indications in three (3) hold-down beam assemblies at Pilgrim Unit 1.
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IE Bulletin N3. 80-07 April 4, 1980 Page 2 of 4 The beam assemblies having crack indications are scheduled for replacement during the current refueling outage of the above units.
A metallurgical analysis has been initiated by GE to determine the probable cause(s) of the cracking.
deneralElectricnotifiedutilitieshavingoperatingBWRunitswithjetpumps of this potential problem on March 17 and 18, 1980.
The NRC staff was advised on March 19, 1980 as to the actions being taken by GE in this regard.
The s.taff was also notified of a hold-down beam failure experienced at a foreign BWR facility.
On the basis of information provided by General Electric and the recent experience at Dresden Unit 3, Quad Cities Unit 2 and Pilgrim Unit 1, concern arises that the hold-down beam assemblies and subsequent jet pump function may degrade significantly during operation. This potential for degradation could lead to jet pump disassembly and possibly reduce the margin of safety during postulated accidents.
The following actions are to be taken by licensees of GE designed 3WR-3 and BWR-4 facilities with operating licenses:
A.
Plants Now in Scheduled Refueling Outage Prior to Restart 1.
Visual inspections assisted by TV camera shall be conducted to assess the integrity of the jet pump structures, the hold-down beam assembly, hold-downs, wedge and restrainer assembly.
Particular attention should be given to areas of unusual wear, failed keeper welds or other evidence of distress that could be indicative of loss of beam assembly preload.
2.
Ultrasonic examinations, utilizing GE precedure TP-508.0642 (Rev. A) or equivalent, shall be conducted to assess the integrity of the jet pump hold-down beams at the nid length ligament areas bounding the beam bolt.
3.
Upon completion of the inspections required by paragraph 1 and 2 above, the appropriate NRC regional office shall be promptly notified, followed by a 14 day written report, on the results of the inspections including any deficiencies thus identified and correc-tive actions taken.
4.
When startup for power operation begins, the surveillance described in Item B.2 shall be initiated.
B.
Plants Currently Operating or Resuming Operations 1.
The NRC staff has determined that the operating plants warrant inspection as required by paragraph 1 and 2 above.
Therefore, licensees are requested to provide within 30 days of receipt of this
IE Bulletin N3. 80-07 April 4, 1980 Page 3 of 4 bulletin, written justification for any continued operation until these inspections are made and any defects thus identi;fied are corrected.
2.
For plants intending to justify continued operations or resume operation, the following surveillance, if not already performed, shall be initiated within 10 days after receipt of this bulletin and shall be continued until the plant technical specifications are revised or the cause of beam failure has been identified and corrected. This surveillance should improve the ability of the plant to identify an early indication of jet pump degradation or failure.
Individual jet pump differential pressure geadings should be recorded and used to establish a data base for expected charac-teristics for each jet pump.
Periodic surveillance readings and individual jet pump trends when evaluated against this data base should assist in providing indication of jet pump degradation and supplement other conditions checked to determine jet pump operability.
a.
Prepare the necessary procedures and perform jet pump opera-bility surveillance including the items specified in b. below on a daily basis, and following recirculation pump restart, and following unexpected changes observed in core flow indications, recirculation system flow indications, or established power-core flow relationships.
b.
If any of the following deviations occur during surveillance, evaluate and record the reason:
(1) The recirculation pump flow differs by more than 10% from the established speed-flow characteristics for that pump.
(2) The indicated total core flow is more than 10% greater than the core flow value derived from established power-
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core flow relationships.
(3) The diffuser to lower plenum dif*erential pressure reading l
on an individual jet pump exceeds the expected charac-teristics established for that pump (B.2 above).
3.
If it is determined that a jet pump is inoperable or significantly degraded, the reactor shall be shutdown in accordance with technical specification requirements.
4.
Review your procedures for instructing plant operators regarding identification and response to sudden individual jet pump failure.
Revise procedures as required and instruct operating staff of any changes.
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IE Bulletin N3. 80-07 April 4, 1980 Page 4 of 4 a
C.
Reporting Requirements TheinformationinItemsA.3,andB.1,isrequestedundertieprovisions t
of 10 CFR 50.54 (f).
Accordingly, you are requested to provide within the time periods specified in these items, written statements of this information, signed under oath or affirmation.
Approved by GAO, B180225 (R0072); clearance expires 7-31-80.
Approval was given under a blanket clearance specifically for identified generic problems.
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Figures 1 and 2 Jet Pump Sketches J
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4 IE Bulletin No. 80-0 7 Enclosure April $/, 1980 RECENTLY ISSUED IE BULLETINS Bulletin Subject Date Issued Issued To No.79-03A Longitudinal Weld Defects 4/4/80 All power reactor In ASME SA-312 Type 304 facilities with an Stainless Steel Pipe OL or CP 80-06 Engineered Safety Feature 3/13/80 All power reactor (ESF) Reset Controls facilities with an OL 80-05 Vacuum Condition Resulting 3/10/80 All PWR power reactor In Damage To Chemical Volume facilities holding Control System (CVCS) Holdup OLs and to those with Tanks a CP 79-01B Environmental Qualification 2/29/80 All power reactcr of Class IE Equipment facilities with an OL 80-04 Analysis of a PWR Main 2/8/80 All PWR reactor facilities Steam Line Break With holding OLs and to those Continued Feedwater nearing licensing Addition 80-03 Loss of Charcoal From 2/6/80 All holders of Power Standard Type II, 2 Inch, Reactor OLs and cps Tray Adsorber Cells 80-02 Inadequate Quality 1/21/80 All BWR licenses with Assurar.ce for Nuclear a CP or OL 80-01 Operability of ADS Valve 1/11/80 All BWR power reactor Pneumatic Supply facilities with and OL 79-01B Environmental Qualification 1/14/80 All power reactor of Class IE Equipment facilities with an OL 79-28 Possible Malfunction of 12/7/79 All power reactor Namco Model EA 180 Limit facilities with an Switches at Elevated OL or a CP Temperatures t
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