ML20009A529

Forwards LER 81-034/03L-0.Detailed Event Analysis Encl

ML20009A529
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/03/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20009A530	List: ML20009A529 ML20009A534
References
P-81158, NUDOCS 8107130278
Download: ML20009A529 (6)

Text

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PLATTEVILLE, COLOR ADO 80651 June 3, 1981 Fo r t S t . Vrain Unit No. 1 P-81158 o\ V/ r 1. y X ,z

                                                                          .      b    'L  i Mr. Karl V. Sey f rit , Director                                 i j[;i,1() 138} D- [;8 Nuclear Regulatory Commission                                            ,,asa umron Region IV                                                      , .\       c w tSSRH       i Of fice of Inspection and Enforcement                         'k'N                          '

611 Ryan Plaza Drive NN. N[@ihg Suite 1000 Arlington, Texas 76012 Re fe rence : Facility Operating License No. DP R- 34 Docket No. 50-267

Dear Mr. Seyfrit:

l E '.os ed plec_,e rind a copy of Reportable Occurrence Report No. 50-267/ l 81-034, Preliminary , submitted per the requirements of Technical Specifi-cation AC 7.5.2(b)2. Also, please find enclosed one copy of the Licensee Event Repo rt for Reportable Occurrence Report No. 50-267/81-034. Very t ruly yours, [ ALO Mu. M Don Warembourg Manager, Nuclear Production DW/ cls En clos ure cc: Director, MIPC sil t' 8107130278 810603 ..- PDR ADOCK 05000267 S PDR

REPORT DATE: June 3. 1981 REPORTABLE OCCURRENCL 034 ISSUE O OCCURRENCE DATE: May 4 1981 __ Page l'of 5 1

FORT ST. V MIN NUCLEAR GENERATING STATICN l

PUBLIC bERVICE CCMPANY OF COLORADO i 16805 WELD .00NTY ROAD 19 1/2 PLATTEVILLE, COLORADO S0651 REPORT NO. 50-267/81-034/03-L-0 i ! Final IDENTIFICATION OF i OCCURRENCE:  ; On Monday, May 4, 1981, at 0840 hours, it was determined that equipment necessary to automatically terminate releases from the Fort St. Vrain liquid waste system and the Reactor Building sump was not operating properly. This constitutes operation in a degraded mode of , LCO 4.S.2 and LCO 4.8.3 and is reportable per Fort St. Vrain i Technical Specification AC 7.5.2(b)2. EVENT DESCRIPTION: Refer to Figure 1. Effluents from the Reactor Building sump ( OA- ) and ) are disch ged to a common Tine ( he liquid

                               ) leadin   waste to     system the        (

Goosequi@ ll Ditch ( ). Circu': ting water blowdown ( @ g) is admitted for dilution purposes prior to the e f f' erit reacni the Goosequill Ditch. Radiation monitors RIS-6212 orid RIS-6213 ( and @ ) in the common cischarge line alarm at preset values on hign activity in effluent discharged from either the Reactor Building sump or the liquid waste system and provide a signal 4 to rip the liquid waste transfer pumps ( ), close HV-6212 ( ), and if the release is from the Reactor B lding sump, close HV 04-2 ( @ ), thus terminating the release. ! Circulating water blowdown (dilution) flow is monitored by flow ( ) and at a preset vaYue of Iw blowdown j\ switch FSL-4101 (cilution) flow prov ( @ ides a signal to close HV-6212 () and trip and Reactor ilding sump the liquig pumps ( U7 w}aste

                                           ).           transfer pumps ( @ )

Radioactive liquid waste release numoer 455 was started at 1745 hours on April 29, 1981, and terminated at 2200 hours on April 29, 1981. The recow. ended release rate was 10 gpm, and the recommended circulating wate- blowdown (dilution) rate was 1100 gpm. Prior to initiating the release, Operations personnel, per Surveillance Requirement SR 5.3.2bc-M, adjusted the circulating water blowdown (dilution) rate to approximately 1300 gpm, and then throttled down the dilution flow using flow cont. roller FC-4101 until the dilution i flow rate went below the recommended value. The automnic contro system described earlier resconded prcperly, and the release was i l m-

4 . . REPORTABLE OCCURRENCE 81-034 ISSUE O

                                                     ~

Page 2 of 5 begun upon completion of the surveillance. The circulating water blowdown (dilution) flow rate as indicated on flow recorder FR-4101, , was 1310 gpm at the start of the release. t At approximatelv 2145 hours on April 29, 1981, Operations personnel discovered that the results of a routine sample of tne Goosequill Diten taken during the release indicated conductivity of 2970 umhos. l Although not in excess of Tecnnical Specification limits, this higher ! than expected value indicated a problem with the circulating water blowdown system. A check of flow recorder FR-4101 indicated blowdown flow in agreemant with the recommended rate, and the release was

;                              allowed to finish.

l Following completion of the release, Operations personnel verified the proper positioning of blowdown valves and completed the post-release flush per Surveillance Requirement SR 5.8.2bc-M. After completing the flush, Operations personnel closed flow control valve i FCV-4101 and verified that flow recorder FR-4101 read 0 gpm. Upon 4 reopening and reclosing FCV-4101, the indication on FR-4101 remained I at 1000 gpm. Operations personnel closed the circulating water

!                              manual blowdown valves and verified that no blowdown flow existed.
!                              FR-4101          still                   indicated 1000 gpm. At this point, Operations

! personnel manually adjusted the blowdown valves to positions .hich would result in approximately 1700 gpm blowdown flow, based or. past experience with the system. FR-4101 indicated 1700 gpm at this time. j Subseouent analysis of circulating water blowdown flow integrator l FI-4101 indicated an average blowdown (dilution) flow rate of 1450 gpm during liquid waste release numoer 455, but since indication l for FI-4101 comes from the same flow element as does indication for FR-4101, the average is suspect. Radiochemical analysi s of the liquid waste system contents prior to release indicatnd a 3H concentration of 6.84E-3 uCi/ml . The results of a roatine sample taken during liquid waste release number 455 indicated a 3H concentration of 4.77E-5 uCi/ml. The average release rate as indicated by flow recorder FR-6215 for release numcer 455 was 8.2 gpm. The calculated average dilution (blowdown) flow rate based on these sample results was 1175 gpm. Based on the above analysis and the prompt investigation by ! Operations personnel, it is concluded that neither LCO 4.8.2 i (radiological) nor LCO NR 1.1 (cnemical) limits were exceeded during liquid waste release number 455. However, it cannot be ensured that the automatic control system required by LCO 4.8.2(d) was operable

;                              during the release, r

I

REPORTABLE OCCURRENCE 81-034 ISSUE O Page 3 of 5 CAUSE DESCRIPTICN: Examination of flow transmitter FT-4101 indicated that both sense lines on the associated flow element were partially plugged. This resulted in the erratic readings on flow recorder FR-4101 and flew integrator FI-4101. CORRECTIVE ACTION: Plant Trouble Report 4-385 was issued on April 29, 1981, indicating the faulty operation on flow controller FC-4101. Plant personnel discovered the partially plugged sense lines and blew out the lines on April 30, 1981. Subsequent testing indicated proper operation of the flow element and auxiliary equipment. No further corrective action is anticipated or required.

i FIGIIRE 1 Circulating Water Blowdown t-- > . [FE ( i . I 1.' -{a) l l i e 8 8 FS L-4101 i ' i 8 8 e et I k.4 - l

                                       @                                                             6213 s     a/                                                                h      _.6212..         ilV 62                                    t
                                                                                                                                                                \      ~/
                  ;-                                                                         g3       13 _ . _ . _
                                                                                                                           -]  N                      l t-                                                                            n>       \m
                                                                                                                  @q                                  ;           \,

l , Coosequill s j '_ L ,_ _ ': Ditch Radioactive 1.1 quid , l Waste (System 62) e 4 i e

                                                                                                                   . _  .i

__ l .I, g j..  %, , a to m h IIV-7204-2 '

                                                                                                                                                                  'S mn

______ . f Q NOTE: For simplicity, only those com- A gg g l ponents referenced in this report o p V , have been included on this drawin< m

              #--- ]                       j~~                             l                      ;         Actual valve positions will depenu                          g l

f__{^}___L _ _ _ _ _ . _ _ _ _ _ _ _s upon the operation taking place, g Reactor $ Building @ Sump (Sys- , l h tem 72)

• V E To Liquid Waste System 8

Trip on Low illowdown Flow

REPORTABLE OCCURRENCE 31-034 ISSUE O Page 5 of 5 Prepared By: NMCb [F. Sk Frecerick J. BoMt Senior Plant Enginear Reviewed B): '4 44

                  / W/ Gans Technical Services Supervisor Reviewed By:          i Frank M. Matnie Operations Manager i

Approved By: d>v dtL**v McLO  % Don Waremoourg Q j Manager, Nuclear Production l l l l}}