05000245/LER-1997-019-01, :on 970326,discovered That Liquid Discharge Radiation Monitor Interlock Setpoint Was Not Set Iaw/Odcm. Caused by Failure to Adequately Implement ODCM Requirements in Procedure.Tagged & Closed Discharge Valve

:on 970326,discovered That Liquid Discharge Radiation Monitor Interlock Setpoint Was Not Set Iaw/Odcm. Caused by Failure to Adequately Implement ODCM Requirements in Procedure.Tagged & Closed Discharge Valve

ML20138C758
Person / Time
Site:	Millstone
Issue date:	04/25/1997
From:	Robert Walpole NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20138C726	List: 05000245/LER-1997-019, Forwards LER 97-019-00 Which Documents Event That Occurred at Mnps,Unit 1 on 970326.Commitments Made within Ltr, Submitted 05000245/LER-1997-019-01, :on 970326,discovered That Liquid Discharge Radiation Monitor Interlock Setpoint Was Not Set Iaw/Odcm. Caused by Failure to Adequately Implement ODCM Requirements in Procedure.Tagged & Closed Discharge Valve
References
LER-97-019-01, LER-97-19-1, NUDOCS 9704300194
Download: ML20138C758 (3)

LER-1997-019, on 970326,discovered That Liquid Discharge Radiation Monitor Interlock Setpoint Was Not Set Iaw/Odcm. Caused by Failure to Adequately Implement ODCM Requirements in Procedure.Tagged & Closed Discharge Valve

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
2451997019R01 - NRC Website

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROYED BY OMB NO. 3160-0104 (4 95)

EXPIRES 04/30/98

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FACIUTV NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Millstone Nuclear Power Station Unit 1 05000245 1 of 3 TITLE 14)

Liquid Discharge Without SW or Recirc Water Available EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY YEAR FAclWTY NAME DOCKET NUMBER NUMBER 03 26 97 97 019 00 04 25 97 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMEN1S OF 10 CFR i: (Check one or more) (11) 20.2201(b) 20.2203(a)(2)(v)

X so.73(a)(2)(i) 50.73(a>(2)iviii)

MODE (M LEVEL (10) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)

POWER 20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(aH2)(iii) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv)

OTH*R or in NRC Form 366A 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (Include Area Codel Robert W. Walpole, MP1 Nuclear Licensing Manager (860)440-2191 i

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) i l

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE I

TO NPRDs TO NPRDS j

SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR

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YES g

SUBMISSloN NO

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(if yes, complete EXPECTED SUBMISSION DATE).

l hSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

Millstone Unit One Technical Specification 3.8.A requires that the liquid radwaste effluent line radiation monitor setpoint be set in accordance with methods and parameters as described in the Offsite Dose l

Calculation Manual (ODCM). The ODCM specifies a fixed, default setpoint when liquid radwaste radioactivity concentration is below a certain level assuming a minimum dilution flow during discharge of 110,000 gpm.

Contrary to this requirement the default setpoint has been used with dilution flows less than 110,000 gpm.

l Thrre were no safety consequences for this event since the discharge procedures had administrative controls to ensure releases were below 10CFR20 limits. The safety significance of this event is the conduct of a l

liquid radwaste discharge with an incorrect setpoint for the existing plant conditions.

l l

The cause of this event was a failure to adequately implement ODCM requirements in a procedure. The radwaste discharge valve was tagged closed as a corrective action until changes to the operation's procedure l

SP 671.5 was completed. The chemistry procedure will be changed to a surveillance and will be revised to implement the assumptions and conditions from the ODCM concerning use of the liqv;d radwaste monitor dsfeult setpoint. The ODCM will be revised to address special conditions during shutdown when determining i

effluent monitor setpoints. The procedure controlling ODCM changes will be revised to requ;re the Chemistry Manager to review and sign to ensure unit procedures reflect ODCM changes.

9704300194 970425 PDR ADOCK 05000245 S

PDR

9 NRC FO~.M 366A U.S. NUCLEAR REGULATORY COMMISSION E95)

UCENSEE EVENT REPORT (LER)

TEXT CONTINUATION l

FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEOuENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 2 of 3 97 019 00 TEXT (11more space is required use addotionalcopies of NRC Form 366A) (11) 1.

Description of Event

On March 26, it was discovered that the liquid discharge radiation monitor interlock setpoint, under certain conditions, was not being set in a manner consistent with one of the parameters specified in the Offsite Dose i

Calculation Manual (ODCM). The ODCM requires a setpoint of two times the activity concentration in the i

tank to be discharged or a default setpoint of 9.4E-5 Ci/ml, whichever is greater. The default setpoint is j

based on a maximum radwaste discharge flow of 350 gpm, a minimum dilution flow of 110,000 gpm, and an isotopic composition which would require the use of a limiting concentration of 3E-7 Ci/ml. Unit Chemistry a

uses Procedure CP809A to determine the setpoint for each discharge and records the required setpoint on the discharge permit. Unit Operations implements the setpoint during discharge via procedure OP312A (steps for sstting of the radiation monitor setpoints have recently been removed from OP312A and placed in SP671.5).

During plant outages the available dilution flow may be less than 110,000 because of circulating water system outage. This condition occurred in 1991 because of a Unit One circulating water system outage and again starting in 1996 when all three Millstone units were shutdown. This created a condition where discharges from Unit One were performed using the default setpoint with less the.n the required 110,000 gpm dilution flow.

The implementing Chemistry procedure had no provision for a';suring the minimum required dilution flow when using the default setpoint, f

11.

Cause of Event

l i

The cause for this condition was an assumption that a dilution flow rate of 110,000 gpm would always be available during liquid radwaste discharges. Therefore, putting this basis informatior, into the ODCM, and not into the procedure at that time seemed to be adequate.

Ill. Analysis of Event i

On January 1,1986 the ODCM became part of the Radiological Environmental Technical Specifications (RETS)c Revision 0 of the ODCM specified that the liquid effluent monitor trip setpoint be set at two times the activity concentration in the tank to be discharged. There was no provision in Revision 0 for a default setpoint. The ODCM also limits discharge flow so that expected radioactivity concentration at discharge, based on chemistry sample analysis, does not exceed one-tenth (0.1) of the limits. Therefore the interlock setpoint is set by ODCM requirement at one-fifth (0.2) of the limits.

l Because of decreasing activity concentrations in liquid discharge it became increasingly difficult to discharge I

liquid radwaste without tripping the interlock and automatically terminating the discharge. Therefore the

(

ODCM was revised in June,1990 to allow for a default setpoint of 9.4E-5 Ci/ml if the setpoint based on two times the activity is lower. One of the assumptions specified in the ODCM for the default setpoint is a i

minimum dilution flow of 110,000 gpm based on one Unit 1 circulating water pump of 100,000 gpm and one 3

Unit 1 service water pump of 10,000 gpm.

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l N,RC FORM 36CA U.S. NUCLEAR REGULATORY COMMISSION l,

(4-99 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 3 of 3 97 019 00 TEXT fit more space is required, use additional copies of NRC Form 366A) 117)

Unit One Chemistry revised CP809A, " Liquid Waste Discharge", to use the default setpoint. The revised procedure did not specify that a minimum dilution flow of 110,000 is required when using the default setpoint.

Because of a circulating water system outage in 1991 Unit 1 was allowed to take credit for dilution flows from Units 2 and 3 during discharge. The need to maintain concentrations below 10CFR2O limits were j

addressed but there was no consideration of monitor setpoint parameters.

During 1996 all three Millstone units were shutdown creating a special condition where Unit 1 minimum dilution flow required by the ODCM could not be achieved, even when taking credit for dilution flow from other units. During this time Unit 1 discharged liquid radwaste using the default setpoint with dilution flows of less than 110,000 gpm required for using the default setpoint.

IV. Corrective Action

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1. The chemistry procedure will be changed to a surveillance Procedure and revised to implement the assumptions and conditions from the ODCM concerning use of the liquid radwaste monitor default setpoint by 7/30/97.

2. The unit chemistry procedures will be reviewed to ensure compliance with effluent Technical Specifications I

by 7/31/97.

3. The procedure governing ODCM revisions will be revised to require the Unit Chemistry Manager to review and sign to ensure unit procedures comply with ODCM changes by 7/30/97.

4. The ODCM will be revised to allow flexibility during shutdown to address special conditions when determining effluent monitor setpoints by 12/31/97.

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V.

Additional Information

None.

Similar Events

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Manufacturer Data None.

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