ML20091Q402

Special Rept SP-N1-84-02:on 840512,specific Activity of RCS Exceeded Tech Spec Dose Equivalent I-131 Limit of 1.0 Uci/G.Caused by Minor Fuel Element Defects.Primary Coolant Sampled & Analyzed

ML20091Q402
Person / Time
Site:	North Anna
Issue date:	06/07/1984
From:	Harrell E, Herrell E VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
N-84-011, N-84-11, SP-N1-84-02, SP-N1-84-2, NUDOCS 8406140018
Download: ML20091Q402 (5)

Text

-

rc 9 .

VIRGINI A ELCCTRIC AND POWCl; COMP ANY NORTH ANN A POWER ST ATIC M P. O. BOX 402 MINER A L. VIRGINI A 23111 June 7, 1984 U. S. Nuclear Regulatory Commission Serial No. N-84-011 Document Control Desk N0/RST: 11 016 Phillips Building Docket No. 50-338 Washington, D.C. 20555 License No. NPF-4

Dear Sirs:

Pursuant to North Anna Power Station Technical Specifications, the Virginia Electric and Power Company hereby submits the following Special Report applicable to North Anna Unit No. 1.

Report No. Applicable Technical Specifications Special Report SP-N1-84-02 T.S. 6.9.2.f This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be forwarded to Safety Evaluation and Control for their review.

Very Truly Yoitrs

/

E. Wayne rrell Station anager Enclosures (3 copies) cc: Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 2900 Atlanta, Georgia 30303 0406140018 840607 PDR ADOCK 05000338 j/}*'%

6 PDR s\

^

5 ,

r

Virginia Electric and Power Company-North, Anna Power Station.. Unit No. 1 Page 1 of.1 Docket No. 50-338

. Special Report No.'-SP-N1-84-02 Description of Event On . May 12, 1984, following a Unit I shutdown from 100 percent

- power,;the specific'. activity.of the Reactor' Coolant System exceeded the

'.TechnicallSpecification Dose Equivalent I-131 limit of 1.0 microcuries  :

per: gram.~ .The limit was exceeded for less than 29 hours3.356481e-4 days <br />0.00806 hours <br />4.794974e-5 weeks <br />1.10345e-5 months <br /> and reached a peak of 1.94 microcuries per gram. This event is contrary to T.S. 3.4.8

and is reportable pursuant to T.S.' 6.9.2.f.

~

Probable Consequences of Occurrence M -

.The Dose Equivalent I-131 specific activity- exceeded the 1.0 microcuries per. gram T.S. limit for'less than the 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> ~ allowed by Lthe Action' Statement of T.S. 3.4.8; therefore, the health and safety of-the general-public;were not affected.

Cause of Event

• Lon May 11', 1984, at 2113 a unit rampdown'was initiated to.begin a

' ~ refueling outage. . The turbine was'taken off line nine hours later. The

. resulting ' iodine spike is an ' expected phenomenon caused. by minor fuel

- . element' defects present in - the ' reactor l core. The_ diffusion of iodine into the reactor coolant was enhanced bp the change in reactor power.

Immediate Corrective Action

- The primary coolant .was sampled and ' analyzed at the accelerated frequmcy required by. item 4a of T.S. 3.4.8 table 4.4-4.

Scheduled Corrective Action None required..

Action Taken To Prevent Recurrence f

No further action required.

. Generic Implications Iodine spiking as a recurring phenomenon in Unit I and-has been previously reported.:

4 J. _

ip

-e- ,

J -:

~

Attachment:

Page 1 of 3 s [ Supplemental Information'- 'a This . event 1is : reportable as a "Special Report" pursuant' to T.S.

6.9.2. .Ic '11 tion the supplemental information required by T.S. 3.4.8

is. included as follows:

1.: Reactor' Power. History-48' hours prior to the event:

- DATE TIME POWER- MWe COMMENTS

. ;05-10 0000-2400 100% 945 A 05-11 0000-2113: 100% 945 B 05-11484 2200 90% 855 05-11 2300 75% 728 05-11-84 2400 68% 663' 12-84 '0100 53%~ 513 N: 05-12-84' 0200 '50% '470 1

05-12-84 0300- -41% 365

---.. '05-12-84 0400 29% '244

.c l- 05-1,2-84 f {0500- -28% 240-

05-12 0600 .11% 74 ~C

.g 05-12-84 0700L 0%- _

0 -D A) Steady' state power operation.-

B) Began rampdown at 2113 to begin refueling outage.

Turbine taken-off line at 0611.

~

C)1 D) LReactor taken subcritical at 0644.

i t

i k.k5 b

[oio t

['

t c

R<

a -

-. .~.:.

Attachment:

Page 2 of 3 1 ,

2.- -Fuel Burnup by, Core Region - As of'May 12, 1984:

EsyF ' <

FUEL BATCH BURNUP (MWD /MTU)

'4A2 34,268 SA 28,750 6AL - 14,987

'3 . Clean 'up flow history (one mixed -bed demineralizer in service):

• AVERAGE-FLOWRATE.

-(GALLONS PER DATE- TIME MINUTE)

?-c '05-10-84. '0000-2400 125 05-11-84 0000-0327 126 05-11-84 0327-2400 78 05-12-84 0000-0133 78 05-12-84: 0133-0930 125

4. History of . degassing operations 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the first sample exceeding the T.S.' limit:

'De-gassing operations were performed intermittently between 0320 and 1520 on 05-11-84.

5. - Duration of Dose Equivaleat I-131 above~1.0 microcurie / gram:

DOSE EQUIVALENT ~

.DATE TIME .I-131 (MICROCURIES/ GRAM) 05-11-84 0120 0.116 05-12 0316 0.251

'05-12-84' 0930 1.94 i

,05-12-84 1230 1.92 05-12-84 .1630 1.44

~

an Jh

s, e 7.

'Y i -; ^Y .b Q .t y c ;t .i

Attachment:

, Page 3 of 3 DOSE EQUIVALENT DATE' . TIME _ I-131 (MICR0 CURIES / GRAM) 05-12-84 1830 1.38

=' '05-12 2030- -1.43 05-13-84 . 01'08 '1.42 1

05-13 0408' ~ 1.07

~

05-13'-84 0808. 0.95 t- "l). ,

• '05-13-84' 1205 0.621 13-84. 1625 0.459~

4 -

05-13 0231 0.278 pk W

y

~

2 l

5 4