PNO-II-80-119, on 800628,76 Control Rods Failed to Fully Insert During Routine Shutdown.Manual Scrams Failed to Effect Repair.Auto Scram Caused Full Insertion.Cause Being Investigated.Confirmation of Action Ltr Issued
| ML18025A986 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/30/1980 |
| From: | Julian C, Robert Lewis NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| References | |
| PNO-II-80-119, NUDOCS 8007240256 | |
| Download: ML18025A986 (4) | |
PRELD)INARV NOTIFICATION J~e 30, l980 Page I of 2 PRELIMINARY NOTLJ:iCATION OF FVF2lT OK VISUAL OCCURRENCE PNO-II-80-119 a
. P
':I,"
a IE staff as of this date initiall known'bv FACILITY:
Teaaeaaee Valley Aaahortl.y Broaae Ferry Unit. 3 Docket lIo. 50-296 Athens, Alah<<ma RmuECr:.
FAILURE OF COIITROL ROUE TO lttsERT UURZttC A Sctlatt At J:30 a.m.
on Junc 28, seventy six control rods faiicd to fully insert. during a routine shutdown.
The re<<cLor was manually scrammed from about 3QQ power to eHect repair to the fccdwater systen.
Following the manual
- scram, 76 of Lhe 185 control rods failed to fu1 ly insert.
The p<<rtially inserted rods were all on the. east side of the core.
Reactor power level was indicated to be less than one percent in the east si~le of the core.
The'west side of Lhe core was subcriti-c<<l.
A second manual scram was iniLiatcd four minutes later and a%i partially inserted rods ~ere observed to dr'ivc inward buL 59 remained partially withdrawn.
A third manual scram was made one minute later and 47 rods'remained p<<rLiallv withdrawn.
Core coolant f1nw, temperature
<<nd prcssure remained normal for plant conditions.
Six minutes late>>
an automatic scram occurred from a scram dischqrge volume tank high water level signal.
A11 Lhe rods full inserted at this time.
The unit remains shutdown and Lhe cause is sti11 under investigation.
No definite cause h<<s been determined at this time but thc problem appears to be hydraulic in nature.
Thc scram discharge volume, which receives scram discharge water from the east control rod drive units, is postu1<<ted to have been parLia3.Ly filled before the event;
- however, no level <<nnunciation was received prior to shutdown.
A Confirmation of Action I,etter is being issued, requiring the licensee to heep the plant shutdown pendiug completion of their investigation of thc failures
<<nd completion of corrective actions.
A restart will not occur without NKC concur-rencee A Region II inspector w<<s dispatched to the site to assist the resident inspectors on June 28.
Two NBC resident inspecLors are onsite and a Region If, supervisor is enrautee Hcdia interest has occurred.
A news release was made by the licensee.
The NRC plans no news relcasc at'his Lime.
The State of Alabama has been informed.
Tha NRC FWergenry ReSpcnSe Center rCCeiVed uutifiCati.On Of this OCqurrenCe by teiephonc from the; licensee at 2:25 <<.m.
CDT on June 30e This information is current as ot ll:30 a.m.
on Zunr. 30.
C/R DIST.CHM.CMRS. PEeGC.C~..
Canaan:
C. Jal tan, Rll 242-5533; R.
C. Lea 80 O'V E<OE5<
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PBFLD>iNARY NOTIFICATTOZ Page 2 of 2 PNO-II-80"119 Distribution:
TransmiI.ted 8
Chaitstan Ahaa mr.
Commissioner Giiinsky Commissioner Kennedy Transmitted:
tiSRR~P.
Vi, J. Dircks, EDO C. Nicheison, AEOD J. J. Fouehard, PA
's..'1. Hailer, MPA R.
C. Ryan, SP
- 11. K. Shapar, EK3 Appiioahle Resident Sita St.
. Commissioner 11endrid.
Commissionet Bradford ACRS P 'ids.gas E. R. Deutonpi N
R. S. Yollmer, NRR R. J. Mattson, NRR D. F. Ross, NRR D. Fisenhut,
%K S. E. Hanaue~r, NRR Villste J.
G. Davis, R7MSS R. J. Bndnit.z, RES
- 8. J.
Chil@,
SECY C.
C. Kammererp CA (For Distribution)
IE:XOOS~Z':RO Dist.)
Landov (6 min/page)
J.
4 Cummings s OIA HAIl R. Minogue, SD 1E:ZOOS Document Hgt. Br. (For PDR/LPD PKELlHINARY NOTIFTCAT70V