ML18065A860

LER 96-006-01 on 960207,discovered Limits of Design Analysis Could Have Been Violated.Subsequent Tests & Analyses Facility Did Not Exceed Basis.Operating Procedures Have Been Revised to Treat 2530 Megawatts Limit as Absolute Limit

ML18065A860
Person / Time
Site:	Palisades
Issue date:	08/02/1996
From:	Flenner P CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18065A859	List: ML18065A858 ML18065A860
References
LER-96-006, LER-96-6, NUDOCS 9608140240
Download: ML18065A860 (4)

Text

NRC FORM 366 (4195)*

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150--0104 EXPIRES 4130/98 ESTIMATED~ PER RESPONSE TO COllPL Y wmi THIS llANDATORY INFORllATION COU£CT10N REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED

-* - LICENSEE EVENT REPORT (LER) INTO THE LICENStHG PROCESS NID FED BACK TO INDUSTRY. FORWARD COllllEHTS REGARDING BURDEN ESTIMATE TO THE INFORllATION NID.RECOROS -GEllEHT BRANCH (T-<I F33), U.S. "-'Ct.EAR REGUIATORY COlllllSSION. WASHINGTON, DC 2QS5S.

0001, NID TO THE PAPERWOR~ REOUC'TION PROJECT (315G-010C, OFFICE OF (See reverse for required number of digits/characters for each block) -aEllEHT NID BUOGET, WASHINGTON, DC 20503 FACILITY NAME (1) DOCKET NUMBER (2) Page (3)

PALISADES NL)CLEAR PLANT. 05000255 1of4 TITLE(4)

LICENSEE EVENT REPORT 96-006 REACTOR POWER LICENSE LIMIT- VOLUNTARY SUPPLEMENTAL REPORT EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) .

• OTHER FACILITIES INVOLVED (8).

YEAR , . SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER MONTH DAY YEAR MONTH DAY .YEAR

_ NUMBER NUMBER 05000 02 07 96 96. - 006 - 01 08 *02 96 FACILITY NAME DOCKET NUMBER 05000 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check one or more) (11)

MODE (9) 20.2201(b) 20.2203(a)(2)(v) 50.73(a)(2)(1) 50. 73(a)(2)(iii)

N I POWER LEVEL (10) I I 100 20.2203(a)(1) 20.2203(a)(2)(1) 20.2203(a)(3)(1) 20.2203(a)(3)(ii) 50.73(a)(2)(ii) .

50.73(a)(2)(iii) x 50~ 73(a)(2)(x) 73.71 l~~~~l:'f, il~:J;,,f 11!!~1 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) Voluntary Report 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v) Specify in Abstract below or 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(viil in NRC Form 366A LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (Include Area Code)

Philip D Flenner, Licensing Engineer (616) 764-2544 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE - SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TONPRDS TONPRDS SUPPLEMENTAL REPORT EXPECTED (14) MONTH* DAY YEAR I YES .

If yes COMPLETE EXPECTED COMPLETION DATE x I NO EXPECTED SUBMISSION DATE (15)

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

On February 7, 1996, a planned delithiation procedure was performed in accordance with plant I procedures. As expected, the power level increased during the. procedure. The power level was I controlled and monitored in compliance with the existing procedures and resulted in an indicated I plant power in excess of 100% of licensed power for nine consecutive hours. That indication and I the initial investigation of the associated measurement uncertainties led to the event being 1*

reported as LER 96-006 on March 11, 1996 as a condition possibly outside of the design basis I and in violation of a license condition of 100% power level. LER 96-006 also indicated that our I investigation was continuing. Subsequent-tests and analyses have shown that Palisades did not exceed the established design basis and did not exceed 100% power during the period .in I question. Accordingly, this LER is being reclassified as a voluntary report. 1- .

9608140240 960802 PDR ADOCK 05000255 S PDR

I '

NRC FORM 366a 4195 ..

• LICENSEE EVENT REPORT (LER)

U.S. NUCLEAR REGULATORY COMMISSION TEXT CONTINUATION I

FACILITY NAME 11 l DOCKET12\ LER NUMBER 16)

• PAGE 13\

YEAR SEQUENTIAL REVISION NUMBER NUMBER PALISADES.NUCLEAR PLANT 05000255 2 OF 4 96 006 01 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

EVENT DESCRIPTION J

. *1,(

~; '

. ?f' I

On February 7, 1996, a planned delithiation procedure was performed in accordance with plant I procedures. As expected, the power level increased during the procedure. The power level was I controlled and monitored in compliance with the existing procedures and resulted in the indicated I plant power in excess of 100% of licensed power for nine consecutive hours. That indieation and the initial investigation of the involved measurement uncertainties led to the event being reported as LER 96-006 on March 11 , 1996 as a condition possibly outside of the design basis and in violation of a license condition of 100% power level.

The Palisades operating license authorizes reactor operation "... at steady state power levels not in excess of 2530 Megawatts thermal (100 percent rated power) ... " Palisades' procedures considered this steady state limit to be met if reactor power averaged over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> was below 2530 megawatts .. Minor excursions a,bove 100 percent power were viewed as acceptable as long as peak power did not exceed 101 percent and th~ 24-hour average power was less than 2530 megawatts. The slow power rise caused by dissolved boron removal during delithiation was viewe.d as a transient condition not subject to the steady state limit specified in the license. During a later review of po~er level records, questions were raised about whether 24-hour averaging or 8-hour averaging should be used to assure license compliance, and whether measurement uncert~inties were adequately cqnsidered in the. procedure limit on peak power.

Subsequent tests and analyses have shown that. Palisades did not exceed the establisheq d~sign basis and did not exceed 100% power during the period in question. Accordingly, this LER is being re<?lassified as a voluntary report.

EVENT ANALYSIS Two separate actions were taken during the investigation of this event. These actions were:

1. The calorimetric uncertainty analysis was redone to more accurately reflect the calorimetric uncertainty. This analysis was rigorously reviewed by CPCo and an

. outside contractor with significant experience in uncertainty analyses.

• 2. An ultrasonic flow measurement (UFM) of the feedwater flow, originally scheduled for late 1996 or early 1997, was performed on May 21-22, 1996, to assess the plant

• thermal performance. The UFM provided an accurate measurement of feedwater flow independent of the installed feedwater venturies.

NRC FORM 366a 4195.

• LICENSEE EVENT REPORT (LER)

U.S. NUCLEAR REGULATORY COMMISSION TEXT CONTINUATION I

FACILITY NAME 11l DOCKETt21 LERNUMBER 51 PAGE 13\

YEAR SEQUENTIAL REVISION NUMBER NUMBER PALISADES NUCLEAR PLANT 05000255 3 OF 4 96 006 01 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

The final results from the uncertainty analysis show the actual calorimetric uncertainty to be 1.01 %. When the new calorimetric uncertainty of 1.01 % is added to the maximum power level recorded (100.41%),*the resulting value is within the Palisades Design Basis value of 102%. It is therefore concluded that Palisades did not exceed the design basis throughout this event.

The results of the UFM revealed thafactual power (measured using the UFM results) was 2.2%

less than measured power based on the feedwater venturies. The conservative bias is due primarily toa conservative initial venturi calibration and to venturi fouling. The stated uncertainty for the UFM device is comparable to the stated uncertainty for the feedwater venturies. The UFM device is considered to be more accurate due to rigorous testing by the vendor and the device's independence from fouling. Using the ultrasonic flow results, the maximum power level achieved during the event was 98.2%. It has therefore been concluded that Palisades did not exceed 100%

licensed po\\'.er throughout the event.

SAFETY SIGNiFICANCE Since the investigation showed that the power level remained below 100% and within the design basis at all times, there is no safety significance to this event.

CAUSE OF THE EVENT The ro_ot cause for the event as initially reported. was that the *procedural guidance for the operators regarding compliance with licensed steady-stateJeactor core power levels was not sufficiently conservative.* * *

• CORRECTIVE ACTIONS The following corrective actions were accomplished:

Upon realizing that there was some possibility that the design analyses limit could be exceeded due to measurement uncertainties, immediate direction was given to the Operators to avoid exceeding the power limit of 2530 Mwt and to take immediate action to reduce the power below 2530 Mwt if it was exceeded.

Operating procedures have been revised to treat the 2530 Mwt limit as an absolute limit which would require immediate corrective action if it is exceeded.

NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 4/95 .

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME 11 l DOCKET/2\ LER NUMBER 6l PAGE 131 YEAR I SEQUENTIAL .

NUMBER REVISION NUMBER PALISADES NUCLEAR PLANT 05000255 40F 4

• 96 006 01 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

The calorimetric uncertainty analysis was revi.sed to more accurately refl~ct known **

uncertainties. The ,analysis revealed that Palisades remained within the established design

• basis at all times.

A flow test using UFM 1 originally scheduled for late 1996 or early 1997, was performed May 21-22, 1996. The results of the flow measurement revealed that the installed flow venturies .

have a conservative bias. This resulted in the indicated reactor power reading higher than

. the actual power. The measurement indicated that 100% power was not exceeded

• throughout the event.

PREVIOUS EVENTS No previous events have b~en found.