Semantic search

At 2043 (CDT) on 4-26-06, during a plant shutdown with the reactor at approximately 35% power, the operating crew manually initiated a reactor trip. The operating crew had just stopped one of the two condensate pumps and then the remaining feedwater pump tripped unexpectedly. The operating crew recognized the turbine did not trip, as it is expected to automatically trip when no feedwater pumps are running. The automatic turbine trip would have automatically tripped the reactor. Therefore, the operating crew manually initiated a reactor trip. Because the reactor did not automatically trip (i.e., failure of RPS to initiate and complete a reactor trip), the Shift Manager declared an Alert, at 2049, based on Chart F of Table 2-1 EPIP-AD-02. Therefore, this is a one-hour notification in accordance with 10CFR50.72(a)(1)(i) 'The declaration of any of the emergency classes specified in the licensee's approved Emergency Plan.' The manual reactor trip is reportable (4-hour) in accordance with 10CFR50.72(b)(2)(iv)(B) 'Any event or condition that results in an actuation of the Reactor Protection System (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.' All systems functioned as expected following the manual reactor trip. Service Water Train B is inoperable because of a one-gallon per minute leak. All rods inserted fully. Decay heat is being removed with the steam dump and secondary PORVs. The condenser is losing vacuum due to the turbine trip. Auxiliary Feedwater Pumps started as required. The licensee notified the NRC Resident Inspector.

• * * UPDATE FROM JERRY RISTE TO JOHN KNOKE AT 01:45 EDT ON 04/27/06 * * *

At 2049 on April 26, 2006, Kewaunee Power Station staff declared an Alert emergency classification (reference EN# 42530). The Kewaunee Power Station staff has assessed this event. There was no affect on the health and safety of the general public and no release of radiation. No plant personnel were injured and the only plant equipment problem was with the failure of a trip of both feedwater pumps to cause the main turbine to trip. The Kewaunee Power Plant staff has conducted a preliminary investigation of the control room indications and sequential events recorder, which indicates that before the manual reactor trip there was no automatic reactor trip signal present and a failure of the reactor trip breakers did not occur. The Alert was terminated at 0024 CDT (on 04/27/06). The unit is currently in the Hot Shutdown Mode with plans to cool the plant to less than 350 degrees Fahrenheit. The licensee notified the NRC Resident Inspector and will be notifying State and local government and issuing a press release. Notified NRR EO (MJ Ross-Lee), IRD Mgr (P. Wilson), R3DO (H. Peterson), DHS (Holz ), FEMA (Steindurf), NRC/EPA (Crews), DOE (Wyatt), USDA (Timmons), HHS (Peagler).

• * * UPDATE ON 04/27/06 AT 1718 EDT FROM JERRY RISTE TO ARLON COSTA * * *

When performing a review of the event reported on April 26, 2006 (EN# 42530), the Kewaunee Power Station staff determined another reporting criterion was met. An eight-hour report is required to be made per 10 CFR 50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of 10 CFR 50.72 except when the actuation results from and is apart of a pre-planned sequence during testing or reactor operation.' 10 CFR 50.72(b)(3)(iv)(B)(6) is PWR auxiliary or emergency feedwater system. As described in EN# 42530, a manual reactor trip of the Kewaunee Power Station was initiated at 2043 on April 26, 2006. The manual reactor trip was initiated when the plant experienced a loss of both feedwater pumps. With a loss of both feedwater pumps and a manual reactor trip, the narrow range water level in both steam generators decreased to the actuation setpoint value for starting the Auxiliary Feedwater Pumps, causing all three Auxiliary Feedwater Pumps to start as designed. Because the steam generator water level was below the actuation setpoint, this was a valid actuation of the auxiliary feedwater system. As a valid actuation of the auxiliary feedwater system, this condition is reportable under 10 CFR 50.72(b)(3)(iv). The untimeliness of the report has been entered into the Kewaunee Power Station's corrective action program. The licensee notified the NRC Resident Inspector. Notified R3DO (H. Peterson).

At 1151 CST, the licensee declared an Unusual Event per chart P. At approximately 1115 CST, while filling the CARDOX carbon dioxide (CO2) storage tank, the tank had reached the full mark and the operator requested the trucker to stop filling the tank. The operator verified tank filling had stopped and isolated the fill line at the tank. The operator then isolated the fill line at the truck bay. The fill line relief valve lifted, causing the vent line to bleed CO2 through a weep hole in the tank room. At 1140 CST, the shift manager was informed that CO2 levels in the tank room were at life threatening levels (40,000 ppm at floor level, 30,000 ppm at waist level). At 1155 CST, the shift manager was informed that CO2 concentration had decreased below life threatening levels. At 1215 CST, no further leakage of CO2 through the weep hole into the room was observed. At 1245 CST, CO2 levels in the CARDOX room and adjacent spaces had returned to at or near normal levels. At 1343 EST, the NRC decided not to enter Monitoring mode. The licensee notified the NRC senior resident inspector, along with state and local authorities.

• * * UPDATE AT 1454 EST ON 1/30 2004 FROM J. RISTE TO E. THOMAS * * *

At 1346 the Unusual Event was terminated by the licensee. CO2 levels in all areas of the plant have returned to normal working levels. The CO2 release was terminated at 1239 CST. Notified P. Louden, T. McGinty, T. Reis, FEMA, DHS (D. Lewis)