05000280/LER-1997-005, :on 970502,Unit 1 Power Range Nuclear Instrumentation Was Inoperable Due to Personnel Error.Sro & STA That Were Involved in Event Were Counseled
| ML18153A139 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 05/28/1997 |
| From: | Christian D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML18153A138 | List:
|
| References | |
| LER-97-005, LER-97-5, NUDOCS 9706040089 | |
| Download: ML18153A139 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2801997005R00 - NRC Website | |
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NRC FORM366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB NO. 3160.0104 (4-95)
EXPIRES 4/30/9!1 ESTTMA'!EO BURDEN PER RESPONSE TO COMPLY WITH THIS IMNDATORY INFORPMTION COLLECTION REQUEST: 50.0 HRS.
LICENSEE EVENT REPORT (LER)
REPOR'!EO LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COf.NENTS REGAAOING BURDEN ESTIMATE TO THE INFORPMTION ANO RECORDS I\\WW3EMENT BRANCH (r.e F33),
(See reverse for required number of digits/characters for each block)
U.S. MJCLEAR REGULATORY COf.NISSION. WASHINGTON, DC 20555-0001, ANO TO THE PAPERWORK REDUCTION PROJECT (3160-0104),
OFFICE OF I\\WW3EMENT ANO
- BUDGET, WASHINGTON, DC 20503.
FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE(3)
SURRY POWER STATION, Unit 1 05000-280 1 OF4 lTTlE (4)
Unit 1 Power Range Nuclear Instrumentation Inoperable Due to Personnel Error EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED 8)
MONTH DAY YEAR YEAR SEQUENTIAL REVISION MONTH FACILITY NAME DOCUMENT NUMBER DAY YEAR 05000-NUMBER NUMBER 05 02 97 97
- - 005-00 05 28 97 FACILITY NAME DOCUMENT NUMBER 05000-OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) (11)
. MODE(S)
N 20.2201(b) 20.2203(a)(2)(v)
X 50.73(a)(2)(i)
- 50. 73(a)(2)(viii)
POWER 20.2203(8)(1) 20.2203(a)(3)(i)
- 50. 73(a)(2)(il)
- 50. 73(a)(2)(x)
LEVEL(10) 30%
20.2203(a)(2)(i) 20.2203(a)(3)(ii)
- 50. 73(a)(2)(iii) 73.71 20.2203(a)(2)(11) 20.2203(8)(4)
- 50. 73(a)(2)(1v)
OTHER 20.2203(a)(2)(111) 50.36(c)(1)
- 50. 73(a)(2)(v)
Specify in Abstract below 20.2203(a)(2)(1v) 50.36(c)(2)
- 50. 73(a)(2)(vii) or in NRC Form 368A LICENSEE CONTACT FOR THIS LER 12 NAME I
TELEPHONE NUMBER Onclude Area Code)
D. A Christian, Station Manager (757) 365-2000 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)
EXPECTED MONTH DAY YEAR I YES IX I NO SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE).
DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (18)
On May 2, 1997, with Unit 1 at approximately 30% power, Operations Periodic Test procedure 1-0PT-RX-004, "Reactor Power Calorimetric Using Feed Flow with P-250 Out of Service (Manual)," was completed at 23:20 and the power range nuclear instrumentation (PRNI) channels were adjusted to correspond with the calculated reactor power value of 37.9%. On May 3, 1997, the Shift Technical Advisor discovered an error in the manual reactor power calorimetric that was performed on the previous day. As a result of the error, the calculated reactor power value was approximately 10% higher than the actual value. At 12:52, the PRNI channels were declared inoperable because the channels had been adjusted based on the erroneous reactor power calorimetric. Technical Specification (TS) 3.0.1; requiring the unit to be in Hot Shutdown within six hours, was entered. The PRNI channels were properly adjusted and TS 3.0.1 was exited on May 3, 1997 at 14:49. The event occurred as a result of personnel errors. The personnel who were directly involved in this event were counseled. The safety functions of the PRNI channels were not adversely affected by this event and the health and safety of the public were not affected at any time.
10 CFR 50. 73(a)(2)(i)(B).
9706040089 970528 PDR ADOCK 05000280 S
PDR This event is being reported pursuant to
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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
Surrv Power Station Unit 1 TEXT (If more space is required, use additional copies of NRC Fom 366A) (17) 1.0 DESCRIPTION OF THE EVENT DOCKET 05000- 280 LER NUMBER l6\\
PAGE (3)
YEAR I SEQUENTIAL l REVISION NUMBER NUMBER 97
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00 20F 4 On May 2, 1997, with Unit 1 at approximately 30% power, Operations Periodic Test procedure 1-0PT-RX-004, 11 Reactor Power Calorimetric Using Feed Flow with P-250 Out of Service (Manual)," was initiated at 20: 15. The reactor -power.calorimetric was performed manually because the Prodac 250 (P-250) plant computer system [EIIS-ID] *
.had not been programmed to perform an acceptably accurate calorimetric calculation at the existing lower feedwater temperature. 1-0PT-RX-004 was completed at 23:20 and the power range nuclear instrumentation (PRNI) channels [EIIS-IG,CHA] were adjusted to correspond with the calculated reactor power value of 37.9%.
The calculated reactor power v.alue was not consistent with other plant parameters which indicated that reactor power was approximately 29%. Although some variation is typical, the Operations and Reactor Engineering staff questioned the magnitude of the difference between the calculated reactor power value and the other indications. The staff concluded that continued unit operation was acceptable because the manually
- calculated calorimetric had been independently reviewed and the PRNI channels had been conservatively adjusted with respect to reactor protection functions.
On May 3, 1997, while continuing to investigate the apparent discrepancy, the Shift Technical Advisor (STA) discovered an error in the manual reactor power calorimetric that had been performed on the previous day.. As a result of the error, the calculated reactor power value was approximately 10% higher than the actual value.
At 12:52, the PRNI channels were declared inoperable because the channels had been adjusted based on the erroneous reactor power calorimetric. Technical Specification (TS) 3.0.1, requiring the unit to be in Hot Shutdown within six hours, was entered.
Operations Periodic Test procedure 1-0PT-RX-001, 11 Reactor Power Calorimetric Using CALCALC Computer Program," was changed to compensate for the inability of the P-250 plant computer system to perform an accurate calorimetric based on the existing lower. feedwater -temperature.
The PRNI channels were adjusted in accordance with 1-0PT-RX-001 and TS 3.0.1 was exited on May 3, 1997 at 14:49.
The deviation described above represents an operating condition prohibited by TS Table 3.7-1, which requires a minimum of three operable PRNI channels. Therefore, the event is being reported pursuant to 10 CFR 50.73(a)(2)(i)(B).
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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
Surry Power Station Unit 1 DOCKET 05000 - 280 LER NUMBER (6)
PAGE (3)
YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 97
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00 30F 4 TEXT (If more space Is required, use additlonal copies of NRC Form 366A) (17) 2.0
SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
3.0 4.0 5.0 The error in the manually calculated reactor power calorimetric caused the PRNI channels to be adjusted improperly. As a result, the PRNI indication of reactor power was approximately 10% higher than actual reactor power.
The safety functions of the PRNI channels were not adversely affected by the improper adjustment. The safety actuations that are dependent on PRNI output (e.g., high flux reactor trip) would *have occurred at an approximately 10% lower power level than required.
Furthermore, the high flux reactor trip setpoints [EIIS-JC] had been conservatively reduced to 85% which is a normal practice during unit startup.
Therefore, this event resulted in no safety consequences or significant implications and the health and safety of the public were not affected at any time.
CAUSE
The event occurred as a result of errors on the part of utility-licensed and other utility personnel. Specifically, a calculation error was made by the Unit 1 Senior Reactor Operator (SRO) who performed 1-0PT-RX-004 on May 2, 1997. In addition, the error was not detected during the independent review of the procedure that was performed by the STA.
IMMEDIATE CORRECTIVE ACTION(S)
The PRNI channels were declared inoperable on May 3, 1997, at 12:52 and TS 3.0.1, requiring the unit to be in Hot Shutdown within six hours, was entered.
A Deviation Report was submitted to document the deviating condition and to initiate
corrective actions
1-0PT-RX-001 was changed to compensate for the inability of the P-250 plant computer system to perform an accurate calorimetric based on the existing lower feedwater temperature.
The PRNI channels were adjusted in accordance with 1-0PT-RX-001 and TS 3.0.1 was exited on May 3, 1997 at 14:49.
ADDITIONAL CORRECTIVE ACTIONS
The SRO and STA who were involved in this event were counseled.
The P-250 calorimetric computer program will be changed to enable the program to provide accurate results at lower feedwater temperatures. The appropriate procedures will be revised to reflect the computer program changes.
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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
Surrv Power Station Unit 1 DOCKET 05000- 280 LER NUMBER (6)
YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 97
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00 PAGE(3) 40F4 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) 6.0 ACTIONS TO PREVENT RECURRENCE A Category 1 Root Cause Evaluation (RCE) is being performed to thoroughly examine the causal factors associated with this event. Approved recommendations resulting from Category 1 RCEs are implemented through the Corrective Action Program.
7.0
SIMILAR EVENTS
8.0 LER 50-280/95-011-00: On October 18, 1995, during reactor protection logic testing, source range nuclear instrumentation channels, N31 and N32, were inadvertently blocked due to a personnel error.
Voluntary LER 50-280/94-005-00: On March 30, 1994, Control Room Operators noted that the Unit 1 main generator gross output indication was higher than expected.
Further investigation indicated that the unit had operated at a shift average of approximately 100.5% power. The event was caused by a failure to update the P-250 computer system FLOWCALC program with the most recent revision of the main steam flow transmitter differential pressure span values.
ADDITIONAL INFORMATION
Unit 2 was operating at 100% power and was not affected by this event.