05000255/LER-1996-006, 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:
|
| References | |
| LER-96-006, LER-96-6, NUDOCS 9608140240 | |
| Download: ML18065A860 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2) |
| 2551996006R00 - NRC Website | |
text
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150--0104 (4195)*
EXPIRES 4130/98 ESTIMATED~ PER RESPONSE TO COllPL Y wmi THIS llANDATORY INFORllATION LICENSEE EVENT REPORT (LER)
COU£CT10N REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED 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.
(See reverse for required number of digits/characters for each block) 0001, NID TO THE PAPERWOR~ REOUC'TION PROJECT (315G-010C, OFFICE OF
- - 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).
MONTH DAY YEAR YEAR
,. SEQUENTIAL REVISION MONTH DAY
.YEAR FACILITY NAME DOCKET NUMBER
_ 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)
N 20.2201(b) 20.2203(a)(2)(v) 50.73(a)(2)(1)
- 50. 73(a)(2)(iii)
I POWER I 100 I 20.2203(a)(1) 20.2203(a)(3)(1) 50.73(a)(2)(ii).
50~ 73(a)(2)(x)
LEVEL (10) 20.2203(a)(2)(1) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 73.71 l~~~~l:'f, il~:J;,,f 11!!~1 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) x 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 x I NO EXPECTED If yes COMPLETE EXPECTED COMPLETION DATE 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 procedures. As expected, the power level increased during the. procedure. The power level was controlled and monitored in compliance with the existing procedures and resulted in an indicated plant power in excess of 100% of licensed power for nine consecutive hours. That indication and the initial investigation of the associated 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. LER 96-006 also indicated that our 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 Accordingly, this LER is being reclassified as a voluntary report.
question.
9608140240 960802 PDR ADOCK 05000255 S
PDR I
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- 4195..
U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 11 l DOCKET12\\
PALISADES.NUCLEAR PLANT 05000255 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
EVENT DESCRIPTION
. ~; '
. ?f' LER NUMBER 16)
YEAR I SEQUENTIAL REVISION NUMBER NUMBER 96 006 01
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2 OF 4 On February 7, 1996, a planned delithiation procedure was performed in accordance with plant procedures. As expected, the power level increased during the procedure. The power level was controlled and monitored in compliance with the existing procedures and resulted in the indicated 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.
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- U.S. NUCLEAR REGULATORY COMMISSION 4195.
FACILITY NAME 11l PALISADES NUCLEAR PLANT LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION DOCKETt21 LERNUMBER 51 05000255 YEAR I SEQUENTIAL REVISION NUMBER NUMBER 96 006 01 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
PAGE 13\\
3 OF 4 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. 4/95.
U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME 11 l PALISADES NUCLEAR PLANT LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION DOCKET/2\\
LER NUMBER 6l 05000255 YEAR I SEQUENTIAL.
NUMBER 96 006 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
REVISION NUMBER 01 PAGE 131 40F 4
- 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 UFM1 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.