05000267/LER-1979-053-03, /03L-0:on 791024,total Primary Coolant Oxidants Exceeded 10 Parts Per Million.Caused by off-gassing of Oxidants Due to Reaction of Moisture W/Core Graphite.Power Decreased to Initiate Maint Shutdown

/03L-0:on 791024,total Primary Coolant Oxidants Exceeded 10 Parts Per Million.Caused by off-gassing of Oxidants Due to Reaction of Moisture W/Core Graphite.Power Decreased to Initiate Maint Shutdown

ML19210E325
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/19/1979
From:	Gahm J PUBLIC SERVICE CO. OF COLORADO
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19210E323	List: 05000267/LER-1979-053, Forwards LER 79-053/03L-0 05000267/LER-1979-053-03, /03L-0:on 791024,total Primary Coolant Oxidants Exceeded 10 Parts Per Million.Caused by off-gassing of Oxidants Due to Reaction of Moisture W/Core Graphite.Power Decreased to Initiate Maint Shutdown
References
LER-79-053-03L, LER-79-53-3L, NUDOCS 7912040335
Download: ML19210E325 (1)

LER-1979-053, /03L-0:on 791024,total Primary Coolant Oxidants Exceeded 10 Parts Per Million.Caused by off-gassing of Oxidants Due to Reaction of Moisture W/Core Graphite.Power Decreased to Initiate Maint Shutdown

Event date:
Report date:
2671979053R03 - NRC Website

text

.

REPORT DATE:

November 1% 1979 REPORTABLE OCCURRENCE 79-53 ISSUE O OCCURRENCE DAIE:

Octob er 24, 1979 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMEANY OF COLORADO 16805 WELD COUNTY ROAD 191/2 PLATTEVILLE, COLCRADO 80651 REPORT NO. 50-267/ 79-5 3/03-L-0 Final IDENTIFICATON OF OCCURRENCE:

At approximately 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> on October 24, 1979, with average core outlet temperature greater than 1,200*F, total primary coolant oxidants (the sum of water, carbon dioxide, and carbon conoxide) exceeded ten parts per million.

This constitutes operation in a degraded mode of LCO 4.2.10 and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT

DESCRIPTION

On October 24, 1979, with total orimary coolant oxidants at less than 10 parts per million reactor power was being increased in preparation for approved fluctu-ation testing. At approximately 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> average core outlet temperature exceeded 1,200*F.

The total of primary coolant oxidants at that time was approxi-mately 7.5 parts per million. Following the reactor power increase to approxi-mately 60%, primary coolant oxidants began to follow an upward trend. At approxi-mately 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />, primary coolant oxidant levels exceeded ten parts per million (reference Figure 1, point 1). During the period of fluctuation testing, average core outlet temperature remained above 1,200*F and total oxidants continued to increase.

Fluctuation testing was completed at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> on October 25, 1979, and an orderly shutdewn was initiated for plant =sintenance.

Core outlet temperature was less than 1,200*F by 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on October 26, 1979, (reference Figure 1, point 2) and to further LCO 4.2.10 degraded mode operation occurred.

CAUSE

DESCRIPTION:

The increase in total oxidants is due in part to off-gassing of carbon =enoxide and carbon dioxide as residual primary coolant moisture reacted with the core graphie.e at increased temperatures.

1A72 246 f

7012040h'

REPORTABLE OCCURRENCE 79-53 ISSUE O Page 2 of 4 CORRECIIVE ACTION:

Following completion of fluctuation testing at approximately 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> on Octo-ber 25,1979, orderly reactor shutdown was initiated.

Core outlet temperature was less than 1,200

• F. by approximately 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on October 26, 1979, and no further degr'aded mode operation was observed.

No further corrective action is anticipated or required.

1A72 A7

FIGURE 1: AVERAGE CORE OUTLET TEMPERATURE VERSUS PRIMARY COOLANT OXIDANTS 1350-40

~

38 CORE OUTLET TEMPERATURE 36 34

- 32 a

~

1300 30

- 28 TOTAL OXIDANTS

~

26

^

[

24 m

22 H

x 1

cb y

1250-20 e

m E

18 5 C

x 5

C c

- 16 E

0 H

- 14 s

Ex 12 1200 '

10 8

6 4

2 1150 0

0000 0000 0000 0000 10/24 0/25 10/26 10/27 D*9 0

T 9

g

,j, DATE/ TIME a

REPORTABLE OCCURRENCE 79-53 ISSUE O Page 4 of 4 Prepared by:

'r 4 2M Cathy (C[ H1'rsch T

Techni'chl Services TechniciXn

/

///

c ///

/; su Reviewed by:

7. W. gahm' kechnical Services Supervisor Reviewed by:

Frank M. Mathie Operations Manager Approved by:

7}7m Don Warembourg

/

Manager, Nuclear Production 1472 ;49 O

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSIUN (7*77 T LICENSEE EVENT REPORT CONTROL BLOCK: l l

l l

l l lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6

@ lC l0 l F l S l V l 1 l@l 0 l 0 l-l 0 l 0 l 0 l 0 l 0 l-l0 l 0 l@l 4l ll 1l2 l 0 l@l l

l@

7 8 9 LICENSEE CODE 14 15 LICENSE NUM8ER 25 26 LICENSE TYPE JO 57 CAT 58 CON'T ERC lL @l0l5l0l0 0 l 2 l 6 l 7 @l 1 ' O l 2 l 4 l 7 l 9 l@l 1 l 1 11 l 9 l 7 9l@

"T o

1 7

8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT OESCRIPTION AND PROSABLE CONSEQUENCES h o

2 l At approximatelv 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> on October 24. 1979. with averace core outlet temperature 1 o a j greater than 1,200*F, total primary coolant oxidants exceeded 10 parts per million.

l l This is operation in a degraded mode of LCO 4.2.10 and is reportable per Technical o

4 o

s l Specification AC 7.5.2(b) 2.

No affect on public health and safety.

Similar occur-l o e l rences reported in RO's 77-36, 78-12, 78-18, 78-37, 78-39, 79-01, 79-02, 79-24, 79-30,1 oi7 land 79-45.

I l

o a

80 7

8 9 E

CODE SL8C E COMPONENT CODE SUSCODE SU

.3 E l C l 8 l@ [J_j@

Zl@

Z IZ l Z l ZI Zl ZI@ LZ_j@ l Z i @

o 9

7 8

9 10 11 12

'J 18 19 20 SEQUENTI#6 OCCURRENCE REPORT REVISION LE R'RO EVENT YE A R R EPORT P.O.

CODE TYPE N O.

@ yu RE 7 l9 l l-l l0 l513 l l/l l 01 3 l lL l-l 0l

,_ 21 22 23 24 26 27 28 29 10 31 32 K N A O

Q PL NT MET HOURS 22 58 1 POR B.

SUPPLI E MANUFAC RER IXl@lZl@

lZl@

l Z l@

l 0 10 l 0 l 0 lY l@

l Nl@

l Zl@

lZ Z l Z l Z [@

33 34 35 36 31 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l Cause. of occurrence was off-aassing of oxidants due to reaction of moisture with core '

i o

W graphite. When power was decreased to initiate maintenance shutdown _, no further de-l graded mode operation occurred.

l 7

1 3

l I

l I

i A

7 8 9 80 SA

% POWER OTNER STATUS DIS O RY DISCOVERY DESCRIPTION Xl@ l0 l 6 l 0 l@l N/A l

l Z l@l Personnel Observation l

i s

ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE

@ l d@l N/A l

l N/A l

1 16 7

8 9 10 11 44 45 80 PERSONNEL EXPOSUR ES NUM8ER TYPE

DESCRIPTION

1i7 [_0l0l0l@lZl@lN/A l

(

PERSONNP RIES NUM8ER L FURIPT1CN l 0] 0 l Ol@i N/ A 1

a 7

8 9 11 12 30 LOSS OF OR OAMAGE TO FACILITY

"@i iTI' ~

QqLuf V$3M i

="

i i

e 7

8 9 10 30 e

DE CRIPTION ISSUSEL 81 N/A l

llllllIll{l llj 2

o NAME CF PREPARER PHONE: