05000245/LER-1996-065, :on 961212,liquid Radwaste Effluent Line Monitor Was Not Set Per Requirements of Ts.Caused by Personnel Error.Review of Present Liquid Radwaste Discharge Sys Lineup Will Be Conducted to Determine Configuration

:on 961212,liquid Radwaste Effluent Line Monitor Was Not Set Per Requirements of Ts.Caused by Personnel Error.Review of Present Liquid Radwaste Discharge Sys Lineup Will Be Conducted to Determine Configuration

ML20133G439
Person / Time
Site:	Millstone
Issue date:	01/10/1997
From:	Robert Walpole NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20133G424	List: 05000245/LER-1996-056, Forwards LER 96-056-00 Which Documents an Event That Occurred at Mnps,Unit 1 on 961212,per 10CFR50.73(a)(2)(i). Commitments Made within Ltr,Submitted 05000245/LER-1996-065, :on 961212,liquid Radwaste Effluent Line Monitor Was Not Set Per Requirements of Ts.Caused by Personnel Error.Review of Present Liquid Radwaste Discharge Sys Lineup Will Be Conducted to Determine Configuration
References
LER-96-065, LER-96-65, NUDOCS 9701160046
Download: ML20133G439 (4)

LER-1996-065, on 961212,liquid Radwaste Effluent Line Monitor Was Not Set Per Requirements of Ts.Caused by Personnel Error.Review of Present Liquid Radwaste Discharge Sys Lineup Will Be Conducted to Determine Configuration

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2451996065R00 - NRC Website

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (4-95)

EXPtRES 04/30/98 EO A'1 0 C LECTION RO ST 60 RS E

TED NS nM"'?o^"44."! "^"o%Ka M!a%f" fen ^~84!:

LICENSEE EVENT REPORT (LER) 15m^"u'? '"u's?""#ot"u?o%,"4o"As"s^#%"E'es" e

!?in?!b'~~fol E!.*U#!"#ETM'.%?M"8?M&' *

(See reverse for required number of digits / characters for each block)

Ft.CILITY NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Millstone Nuclear Power Station Uidi 1 05000245 1 of 4 TITLE tel Liquid Radwaste Effluent Line Monitor Not Set Per Requirements of Technical Specifications EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (B)

MONTH DAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY YEAR FACIUTY NAME DOCKET NUMBER NUMBER

' ' ' " ~ '

12 12 96 96 065^

00 01 10 97 OPEHATING THIS REPORT IS SUBMITTED PURSUANT TO THE HEQUIREMENTS OF 10 CFR 5: (Check one or more) (11)

MODE m N

20.2201(b) 20.2203(a)(2)(v)

X 50.73(a)(2)(i) 50.73(a)(2)(viii)

POWER 20.2203(a)(1) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)

LEVEL (10) 000 20.2203(a)(2Hi) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 73.71 20.2203(a)(2)(ii)

.,......,.../.................. -

20.2203(a)(4) 50.73(a)(2)(iv)

OTHER or en NRC Form 366A 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12)

I NAME TELEPHONE NUMBER (mclude Area Codel Robert W. Walpole, MP1 Nuclear Licensing Manager (860)440-2191 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE To NPRDS TO NPRDs SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR SUBMISSION g

YES NO (if yes, complete EXPECTED SUBMISSION DATE).

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

On December 12, 1996, with the plant in the COLD SHUTDOWN condition, a procedure review by a System Manager discovered that the Liquid Radwaste Effluent Line monitor setpoints were not being set correctly. The

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monitor setpoints were set using a less conservative background level. The mon: tor was declared inoperable until a proper method for obtaining the background level is determined. Technical Jpecifications requires that if the trip sstpoints are set less conservatively than the methods specified in the Offsite Dose Calculation Manual (ODCM),

cither release of effluents shall be suspended, the setpoints shall be changed to a proper conservative value, or the monitor shall be declared inoperable. Historically, however, releases continued with the improper setpoints; therefore, this event is reportable as a condition prohibited by Technical Specifications.

Although the trip setpoints were set higher than intended, an evaluation was conducted which determined that additional conservatism in the trip setpoint method ensured that the background changes seen were not high enough to allow discharges which exceeded 10CFR Part 20 limits; therefore, no consequences resulted from this event and the safety significance is low. The corrective actions includes a review of the present Liquid Radwaste Discharge system lineup to determine the appropriate configuration. The discharge procedure will be modified accordingly, as determined by this review, to ensure a proper background levelis accounted for whi,e discharging effluents.

9701160046 970110 PDR ADOCK 05000245 s

PDR

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o eU.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3) j YEAR SEQUENTIAL REVISION

]

Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 2 of 4 96 065 00 1

TEXT (If more space is required, use additional copies of NRC form 366A) f17) l i

1.

Descriotion of Event

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On December 12,1996 at 1110 hours0.0128 days <br />0.308 hours <br />0.00184 weeks <br />4.22355e-4 months <br />, with the plant shutdown and the reactor in the COLD SHUTDOWN i

I condition, a procedure review by a System Manager discovered that the Liquid Radwaste Effluent Line i

j monitor setpoints were not being set correctly. Specifically, use of improperly obtained background level l

reading resulted in setpoints which were less conservative than intended. Technical Specifications require l

that the trip set points for the Liquid Radwaste Effluent Line monitor be set in accordance with the ODCM, which provides a method to calculate the Liquid Radwaste Effluent Line monitor trip points. Then the ODCM j

requires that they be added to the background radiation level indicated on the monitor. This background reading is taken just prior to discharge, and the trip points are set accordingly. In the system configuration t

j prior to discharge, however, the section of monitored piping is drained, resulting in reduced detector j

shielding from external sources, and a subsequent higher background reading then during the subsequent i

discharge.

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This section of piping was drained to prevent leakage past the discharge isolation valves, which had been I

identified in December of 1991. Due to the possibility of an inadvertent discharge, if the system piping upstream of the leaky valves were to become pressurized, the radwaste system valve lineup had been revised to depressurize this section of piping. The revised system lineup was not consistent with the j

system lineup shown in the Updated Final Safety Analysis Report (UFSAR); however, the change was not treated as a change in the operation of the system as defined in the UFSAR, and subsequently did not receive an adequate level of review to determine adverse effects on other plant systems nor was a 10 CFR l

50.59 safety evaluation performed. As a result of this change, the section of piping adjacent to the radiation j

monitor is drained between discharges. During discharge, the piping fills with water, and the background present during the discharge is actually lower than the background reading prior to discharge due to the j

additional shielding provided by the water.

Therefore, although the trip points are set sufficiently 4

conservative to prevent exceeding discharge limits, the trip points present during the discharge are set less conservatively than if the background value during discharge had been used. Since the monitor setpoints

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were set using a less conservative background level, the Liquid Radwaste Effluent Line monitor was declared inoperable until a proper method for obtaining the background level is determined. Technical Specifications i

specifies that if the trip setpoints are set less conservatively than the methods specified in the ODCM, either l

l release of effluents shall be suspended, the setpoints shall be changed to a proper conservative value, or the j

monitor shall be declared inoperable. Historically, however, releases continued with the improper setpoints; l

therefore, this event is reportable pursuant to 10CFR 50.73(a)(2)(i)(B), as a condition prohibited by Technical Specifications.

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11. Cause of Event

5 The cause of the event has been determined to be personnel error in that a failure to properly assess the effects of a procedure change on a plant system lineup as specified in the UFSAR, which resulted in an j

inadequate review of the effects of the change on other plant equipment.

The cause of the problem going unnoticed is attributable to the discharge evolution being a multi-discipline effort. A single organizational entity responsible for the overall effective operation of radiation monitors and j_

cognizant of the entire discharge evolution did not exist.

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'U.S. NUCLEAR REGULATORY COMMISSION i

(4 95)

UCENSEE EVENT REPORT (LER) i TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUddER (2)

LER NUMBER (6)

PAGE (3)

)

l YEAR SEQUENTIAL REVISION i

l Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 3 of 4 l

96 065 00 l

TEXT (11more space is required, use additional copies of NRC Form 366A) (17}

1 111. Analysis of Event i

j Per UFSAR, section 11.5.1, the process effluent radiation monitoring system (RMS) provides a means for compliance with 10CFR20; 10CFR50 Appendix A, Genera! Design Criterias 60, 63, and 64; as well as Regulatory Guides 1.21,1.97, 4.15, and 8.8. Per UFSAR, section 11.5.1, monitoring the radiation level in i

the radioactive liquid discharge effluents, and closing the valves in the discharge line if setpoints are exceeded, is a nonsafety-related functional requirement.

The non-safety related Liquid Radwaste Effluent Line Gross Radioactivity Monitor continuously monitors, measures, and records the activity level in the liquid radioactive waste discharged from the station via the liquid effluent line to the discharge canal to Long Island Sound. These liquids are combined with dilution flow that will result in concentrations less than allowable limits at the plant discharge. The radioactive waste monitor will alarm in the main control room when radiation levels reach the high setpoint. The monitor on this discharge line will also alarm in the main control room if the established Hi-Hi radiation setpoint is exceeded and close the discharge valves in the line, prior to reaching allowable release limits. The system is composed of a shielded scintillation detector positioned on a section of the process liquid piping.

In accordance with Technical Specification 3.8.A.1, the setpoints are to be determined in accordance with methods and parameters as described in the ODCM, which requires calculation of the maximum allowable discharge rate based on the dilution flow rate and a multiplier based on the actual concentration as a factor of the concentration limit for the identified isotope. The dilution flow rate which will be present during the discharge is determined by the number of circulating and service water pumps in operation. The Required Reduction Factor is based on the actual concentration obtained during grab sample as a fraction of the Maximum Permissible Concentrations (MPC) for isotopes in the grab sample. The calculated maximum discharge rate is then reduced by a factor of ten for added conservatism. The ODCM then directs the setting of the effluent line monitor trip points to be whichever is greater, a factor of two times the sampled activity or a minimum stated concentration, and then adds the background level. By discharging at the specified flow rate, these trip points would ensure that the discharge concentration is no greater than one fifth the Technical Specification limit, which is the applicable MPC specified in 10 CFR Part 20, Appendix B.

The background reading is taken prior to discharge, added to the calculated trip settings, and the monitor Hi and Hi-Hi setpoints are set accordingly. Due to several leaking valves in the Radwaste system, procedures were revised to direct the draining of discharge piping upon completion of the discharge evolution. When the piping is drained, shielding, provided by the water in the pipe, is removed from around the detector, which results in an increased background indication. During discharge, the piping fills with water which results in a reduced background level during the time the release is being monitored. Since the trip points have been determined with the higher pre discharge background reading, the trip setpoints during the j

discharge are at a level which is less conservative than that which would be determined using background during discharge.

The setpoints are determined by the Chemistry department, and are based on the sample they obtain. The Chemistry department records the background reading, prior to any involvement of the Operations department, and adds the background to the values obtained as a result of the grab sample. The Operations department obtains the setpoint values from the Chemistry department, sets the monitor trips accordingly on the monitor, and performs the actual discharge. Operations personnel have noticed that the monitor reading decreased when the discharges begin; however, the effect was known to be due to the pipe filling with water.

Since the Chemistry personnel determine the setpoints and Operations is not familiar with Chemistry's methods, the effect on the setpoints was never questioned. The Chemistry Department was

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,U.S. NUCLEAR REGULATORY COMMISelON (4-951 t

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION i

FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 4 of 4 96 065 00 i

TEXT fff more space is required, use additional copies of NRC Form 366A) (17) l not aware that the background level they had utilized to calculate the setpoints would be different during the j

i discharge, and hence never suspected that their trip points were not accurate.

Since neither affected

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department was knowledgeable of the entire evolution, the interrelationship of the setpoints, valve lineup, l

and background level was not fully realized.

a l

Although the trip setpoints were set higher than they would if a representative background level had been i

used, an evaluation was conducted which determined the conservatism in the ODCM method ensured that l

3 the background changes seen were not high enough to allow discharges which exceeded 10CFR Part 20 i

limits; therefore, no consequences resulted from this event and the safety significance is low, i

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IV. Corrective Action

i e

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l A review of the present Liquid Radwaste Discharge system lineup will be conducted to determine the I

appropriate configuration. The discharge procedure will be modified accordingly, as determined by this j

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review, to ensure a proper background level is accounted for while discharging effluents. This will be complete by March 31,1997.

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lt is the expectation of the Station Qualified Reviewer Program to ensure that personnel designated to screen procedure changes for the necessity of a safety evaluation have received the appropriate training.

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j Recently established expectations of system managers provide individuals assigned to specific systems, who j

are responsible to communicate with other plant departments to ensure that their assigned systems, such as l,

the radiation monitors, are operated in accordance with the design basis. This role will enhance the review of j

system changes, as well as increase the level of overall system monitoring. The implementing document for this role will be approved by March 31,1997.

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