ML20141J684

Forwards Draft Public Announcement of Incident Investigation Team Rept on Plant loss-of-power Incident on 900320 for Comments &/Or Suggestions.Announcement Expected to Be Issued on 900608

ML20141J684
Person / Time
Site:	Vogtle
Issue date:	06/04/1990
From:	Ingram F NRC OFFICE OF GOVERNMENTAL & PUBLIC AFFAIRS (GPA)
To:	Jordan E NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
Shared Package
ML20141J689	List: IA-91-468, Partial Response to FOIA Request for Documents.Forwards App F Documents Which Are Being Made Available in PDR ML20141J684 ML20141J692 ML20141J697 ML20141M416
References
FOIA-91-468 NUDOCS 9006120311
Download: ML20141J684 (4)

Text

.- _. ._ ..__ . _ . __ . . _- .

. : o: ..

June 4, 1990 NOTE FOR: Ed Jordan, Director, AEOD l

FROM: Frank Ingram Assistant to the Director Public Affairs Attached is a draf t public announce:r.ent of the Ili report on the Vogtle l

I would appreciate any coments and/or loss-of-power incident on March 20.

' suggestions you ano your staff tr.ny. have and will get a separate copy to Al Chaffee. I would expect to issue the announceraent following the Comission briefing on Friday, June 8.

Frank L. Ingram Assistant to the Director Public Affairs ,

Attachment:

As stated OFFICE: PA. \

HAME: ' Flitgram DATE: '6/4/90 }gv

- lh f i h ~~]'

Y- 9006120311'900604 i 5, '

CF ADOCK 0500r]424' , y pj

" OnAn _.m l

HRC STAFF TEAM COMPLETES INVESTIGATION OF 10SS-POWER-EVENT AT V0GTLE NUCLEAR POWER PLANT l

A NRC staf f Incident Investigation Team (IIT) has completed its review of

- a_ March 20 inrident involving the loss of all electrical pcwer to Unit 1 at The Georgia Power Company's Vogtle nuclear power plant near Augusta, Georgia.

1 team concluded that adequate precursor iaformation was available to make the

)

incident preventable. .

-Unit'l at the Vogtle plant was shut down for refueling on March 20 when a truck carrying fuel and lubricants backed into a power pole, knocking out offsite power to the unit. An on-site backup diesel generator started up but tripped off twice leaving Unit I without electrical power and an operable residual heat removal system for a period of 36 minutes when the diesel was restarted for a third time and began operating properly. As a result, the temperature of the

-reactor coolant increased from about 50 degrees Fahrenheit to about 136 degrees Fahrenheit.

' A Site Area Emergency was declared _but was downgraded to an Alert afGr the diesel generator began operating properly. The Alert was terminated when ,

offsite' power was ' restored-to the unit after about three hours. '

In its report, the team found that this incident was not unique and not- ,

without precedent because loss-of-offsite-power events, loss-of-decay-heat -

Further, removal events _ and diesel generator failures have occurred previously.

' the industry has been informed of these e. vents and the NRC staff and the Institute of Nuclear Power Operations have provided lessons learned and other guidance related to them.

1

" + - -- -- -  ;,, . ._

~ a m

ggggy l

The 11T also concluded that a combination of non-conservative conditions at the +.ime combined with a failure to control work in the switchyard led to the event.- First, two of four sources of offsite power were out of service L- for maintenance. Second, the Vogtle staff had no effective control over the fuel and lubricants truck which could have caught fire as the result of r

electrical arcing. Such a fire.could have caused further damage in the L switchyard and further hampered efforts of the Vogtle staff to restore electrical power. t In addition the Vogtle staff has concluded that it was not necessary to have two of four sourr.es of_ offsite power out of service for maintenance when the water level'in the reactor vessel had been lowered to perform other maintenance work. While_the investigation to determine the root cause of the

backup diesel generator trips is continuing, a preliminary evaluation suggests they_ resulted from_the failure of sensors designed to sht:t down the diesel when cooling water temperatures get too high. A significant number of these sensors

- used at the Vogtle f acility have failed-since 1985.

The IIT also found:that the Vogtle staff's response to the incident .

generally was effective and compensated for weaknesses in their existing procedures. Some weaknesses in their ability to-cope with the conditions .

that would have existed had the residual heal removal systen not been returned to service aho were identified.. ,

TAs a result of this investigation, significant potential generic lessons y were identifjed, including: ,

v 1 4

-.1 b

I l

l ._

~ .

.. , DRAFT "-

\.

L

--approaches to risk management when power reactors are in a shutdown ccndition nead to be developed;

--existing analyses and guidance has not been implemented into procedures and training;

--there is a need for additional analysis of reactor coolant system behavior following the loss of the decay heat removal system;

--existing operating information needs to be further synthesized;

--problems exist with emergency classifications and guidance and implenentation of that guidance;

--technien1 specifications do not take into consideration the risk associated with various configurations of systems that may exist when a powei teactor is in a shutdown condition; and

--at least some diesel generator control and annunicator systems are complex and may not ue well understood.

The 11T was not asked to address possible violations of NRC requirements or resulting enforcement actions which might be associated with the-incident.

Those matters will be addressed separately.

__ - - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _