05000280/LER-2078-012-01, T for Surry Unit 2 Failure to Meet Containment Integrity

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T for Surry Unit 2 Failure to Meet Containment Integrity
ML19105A090
Person / Time
Site: Surry  Dominion icon.png
Issue date: 04/06/1978
From: Stallings C
Virginia Electric & Power Co (VEPCO)
To: O'Reilly J
NRC/IE, NRC/RGN-II
References
LER 1978-012-01T
Download: ML19105A090 (4)
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LER-2078-012, T for Surry Unit 2 Failure to Meet Containment Integrity
Event date:
Report date:
2802078012R01 - NRC Website
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Hr *. J~~s l;' / *0_1 R,eill.y,. Director

'of~ic_e :of* Insp.ElCtion and* Erif~rcemerit

. 'u~. s.*. Nucl<lar Regulatory. Commission..

. Region II - Suite.'818 *:

    • . 230 Peachtree* Street.;* i:forthi-res t<

'Atlnrita, G~o_rgi~

  • 30'303
  • -Dear Mr.* :0 ~Iteilly: :. *

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' ;.i;J Pursuant

  • to :Surry* Pb~'ler Stati,on Te~hniccil. Speci.Ei~ation. 6; 6 ~*z ~ a(L:.),* th*e Virginia Llectr~c and: Pqwer C_ompauy*,hereby.. submits the;. tollo_wing Licer1see Zvent

-~eport: for* Surry \\]nit No~ 2.

. LER-78.:.012/blT--O Thi:s ** report* 1:las been reviewed by the. S t.ation. :~_uclear

  • Safety. and. Opc,irat{tlg
  • CoiJUuittee and.will be* placed>on* th~ agenda for *{h~ nex~ me~ting. of the System..
  • Nuclear Safety* arid* Operating**committee *.

vciry ti;:::

H~ Stalling Vic(~ Pre ide.'tit- -**Powe*. Supply

  • . and P oduttion.op~rations

. iticlo~ure* q copies) cc:. Dr~ f~rn.est Volgenau,. D{r~ct~~. (40. copies)

.. -Of:f:i.ce ~f *11~spection and. Enforcement

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c_opies)'....

Hr~** Wili~ 'G*. McDonald, Director :(3

. Office.o*f ::-'.ianageme~t Inforniat:fon-aud Program.c.outrol:.....
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NRC FORM 366 17-771 *,

U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK: I I G)

IPLEASE PnlNT OR TYPE ALL REQUIRED INFORMATIONI 1

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~IVIAISIPISI 21010101-1010,1010101-101 O!G)l41 ljll 1111G)I I 10

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9 LICENSEE CODE 14

,5 LICENSE NUMBER

~5 26 LICENSE TYPE JO 57 CAT 58 CON'T ITEi 7

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=~~~~~ 1.LJ©I o!5 I ol 010121811101 ol3 l214 l7f 81G)I014 IOl41718!G) 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES@

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!At about 1545, 3-24-78, with the reactor at cold shutdown and loops drain-1 CEifJ I ed, the reactor boro; concentration was reported as 1259 ppm, down 113 ppml

~

!from the previous day's sample of 1372 ppm.

This corresponds to an unplan1

~

fned reactivity addition of*more than 0.5%.

Since containment integrity

~

!was not met, this event is contrary to T.S. 3.8.A.5, and is also report-cu:TI fable per T*.s. 6.6.2.a(4).

The healt_h and safety of the public were not

[))]:] 1affected since the reactor was at all times greater than 4% shutdown.

I 7

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE I Pie I@ l.lU@ LQJ@) !IINI SfTIRJU!@ ~ ~@

9 10 11 12 13 18 19 20

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LEA/AO CVENTYEAR

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REPORT I 7 I 3 I NUMBER

~~ l:=.I 23 SEQUENTIAL OCCURRENCE REPORT REPORT NO.

CODE TYPE Io I 11 21 I /I 10 I 1 I L!J l=1 24 26 27 28 29 30 31 ACTION FUTURE

,' TAKEN' ACTION EFFECT SHUTDOWN

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ATTACHMENT NPR~

PRIMEC.OMP.

ON PLANT METHOD HOURS \\.:.v.

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\\C:J CAUSE DESCRIPTION AND CORREC'rlVE ACTIONS @

SUPPLIER

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REVISION, NO.

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32 COMPONENT MANUFACTURER 80 i HI o 1115 I 44 47 [II£] IA failed capacitor in flow controller FC-2-114 caused the Primary Grade(P§)

[ID:] I water valve* FCV...,;-1-14A to over-feed during blend operations.

The failure

  • c::IJI] 1also interfered with the PG water flow deviation alarm comparator YC-2-114!

OJI] jand no alarms were activated.

The controller was replaced and subsequent I CIJI] I operation was normal.

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STATUS

% POWER OTHER STATUS ~

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9 10 11 80 METHOD OF DISCOVERY DISCOVERY DESCRIPTION 32

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46 80 44 45 80 PERSONNEL EXPOSURES r:;;:;,.

NUMBER r:;:;,, TYPE

DESCRIPTION

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11 12 13 80 PERSONNEL INJURIES Q

NUMBER DESCAIPTION6 EJil lo Io I o l@L------=.!N~A ____________________

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11 12 LOSS OF OR DAMAGE TO FACILITY '4J' TYPE

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ISSUEDC,\\ DESCRIPTION~

ITIJiJ lN.J6 NA NRC USE ONLY 1111111111111 7

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10 68 69 80 NAME OF PREPARER~ __ T_._L_. _B_a_u_c_o_m _______ _

(804) 357-3184 PHONE:------------

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Sur 1~y Power Station, Unit 2 Docket No. 50-281 Report No. 78-012/0lT-O Dilution of Reactor Boron Concentration

1.
2.

Description of the Event At about 1545, 3-24-78, the Shift Supervisor was advised that Unit 2 Reactor boron concentration was 1259 ppm, a reduction of 113 ppm since the previous day's sample of 1372 ppm.

At the time the unit was in cold shut-down, with loops drained and reactor being cooled by the Residual Heat Re-moval System.

This reduction in boron concentraction corresponded to an unplanned reactivity addition of more that 0.5%.

Since containment inte-grity was not set,.this event is contrary to Technical Specification 3. 8.A.5 and is also reportable in accordance with Technical Specification 6.6.2.a(4).

Probable Consequences of the Event The health and safety of the general public were not affected by this event since the reactor was at all times greater than 4% shutdown, The event was identified by routine surveillance practices intended in part to detect problems of this nature.

3.

Cause of the Event

A filter capacitor in the internal power supply of Flow Controller FC-2-114 failed open.

This permitted an AC signal to be introduced into the Flow Transmitter loop.

The effect of this AC injection was to cause the controller to conunand the Primary Grade (PG) flow control valve to go full_

open and deliver about 150 gpm of PG water instead of 100 gpm as demanded by the setpoint control.

A_secondary effect of the AC injection was to prevent the Dual Comparator YC-2-114 output relays from deenergizing and causing flow deviation alarms.

Without the alarms, the operators were not alerted to the excess water flow condition.

Upon identification of the event, a sample of the blender output was taken and analyzed at 1042 ppm.

(It should be noted that had the event proceeded undetected for an extended period of time, the reactor would never had been less that about 2.3% shutdown.

The required shutdown margin 1%.)

From a review of logs and process computer alarm printouts, it was judged that the dilution occurred in the period 1600/3-23 to 0540/3-24.

4.

Immediate Corrective Action

Initial attempts at troubleshooting the PG flow control system were inconclusive but a measure of blend control was achieved by adjusting the water and boric acid setpoints.

Detailed troubleshooting identified the faulty controller.and it was replaced.

Subsequent operation was norma_l.

5.

Scheduled Corrective Action Vendor is being asked to make a design study to determine if hardware changes can be made which would prevent a simular occurrence.

Surry Power Station, Unit 2 Docket No. 50-281 Report No. 78-012/0lT-0 Dilution of Reactor Boron Concentration

6.

Action Taken to Prevent Recurrence 7~

Current operator observation techniques and existing surveillance pro-grams will suffice tcr counter a recurrence.

Generic Implications This event is not considered to have generic implication.

The failure of the electronic element that caused this event is considered to be a ran-dom age failure.

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