| Comanche Peak 1 | 100 |
| Comanche Peak 2 | 100 |
| Cooper | 100 |
| Diablo Canyon 1 | 48 |
| Diablo Canyon 2 | 100 |
| Grand Gulf 1 | 100 |
| Palo Verde 1 | 100 |
| Palo Verde 2 |
The Fight to Tame a Swelling River With Dams Outmatched by Climate Change
Along the Missouri, John Remus controls a network of dams that dictates the fate of millions. ‘It was not designed to handle this.’
By Tyler J. Kelley
March 21, 2019
There were no good choices for John Remus, yet he had to choose.
Should he try to hold back the surging Missouri River but risk destroying a major dam, potentially releasing a 45-foot wall of water? Or should he relieve the pressure by opening the spillway, purposefully adding to the flooding of towns, homes and farmland for hundreds of miles.
Mr. Remus controls an extraordinary machine — the dams built decades ago to tame a river system that drains parts of 10 states and two Canadian provinces. But it was designed for a different era, a time before climate change and the extreme weather it can bring.
“It’s human nature to think we are masters of our environment, the lords of creation,” said Mr. Remus, who works for the United States Army Corps of Engineers. But there are limits, he said. And the storm last week that caused him so much trouble was beyond what his network of dams can control.
“It was not designed to handle this,” he said.
The storm, the “bomb cyclone” that struck the upper Midwest, dumped its rain onto frozen soil, which acted less like dirt and more like concrete. Instead of being absorbed, water from the rain and melted snow raced straight into the Missouri River and its tributaries…
These rising river levels mean the unthinkable is possible: that 2019 could be the year that two terrible flood years — the devastating flooding on the Elkhorn River in 2010 and the record-shattering flood of 2011 on the Missouri River — wrap into one.
“The 2011 flooding was probably one of the bigger disaster events in our history. I think we can safely say ... this event rivals it,” said Bryan Tuma, assistant director of the Nebraska Emergency Management Agency.
Deadly, Historic Midwest Flooding Threatens Ericson Dam, Nuclear Plant in Nebraska
By Pam Wright and Ron Brackett
2 hours ago
weather.com
Flooding in parts of the Midwest has left one man dead threatens a Nebraska dam and nuclear power plant as heavy rains mixed with a melting snowpack swell waterways to historic levels.
An unidentified Nebraska farmer was killed Thursday after the tractor he was using to try and save a stranded motorist was carried away by floodwaters, the Omaha World-Herald reports. The incident occurred at Shell Creek near Columbus, in eastern Nebraska.
Ericson Dam in north central Nebraska is at risk of failing as the Cedar River continues to rise, according to a report by the National Weather Service.
Officials in Boone County, downstream from the dam, also warned of the "imminent failure" of the dam, Boone County News reported.
Both agencies are warning impacted residents to seek higher ground.
In Nebraska, a utility company was placing sandbags around a threatened nuclear power plant Thursday as the Missouri River continued to rise, the Omaha World-Journal reports.
Mark Becker, spokesman for the Nebraska Public Power District, told the newspaper that should the river hit the level of 45.5 feet as projected by the National Weather Services this weekend, the Cooper Nuclear Station, which accounts for 35 percent of NPPD's power, will have to be shut down.
(MORE: Flooding Continues in the Plains, Midwest As Snow Melts; Severe Threat Waning in Midwest, South)
Becker noted that should the plant shut down, DPPD will be able to get power elsewhere and they don't expect the closure to lead to outages.
On Thursday, DPPD lost another small electrical plant when the Spencer Dam failed at the Niobrara River and caused a large ice floe to jam a hole in the building. Workers inside the building were uninjured, Becker told the newspaper. The failure also forced the evacuation of dozens of residents along the river.
Nuclear industry pushing for fewer inspections at plants
FILE - In this March 16, 2011, file photo, steam escapes from Exelon Corp.'s nuclear plant in Byron, Ill. (AP Photo/Robert Ray, File)WASHINGTON (AP) — The nuclear power industry is pushing the Nuclear Regulatory Commission to cut back on inspections at nuclear power plants and throttle back what it tells the public about plant problems. The agency, whose board is dominated by Trump appointees, is listening.Commission staffers are weighing some of the industry's requests as part of a sweeping review of how the agency enforces regulations governing the country's 98 commercially operating nuclear plants. Recommendations are due to the five-member NRC board in June.Annie Caputo, a former nuclear-energy lobbyist now serving as one of four board members appointed or reappointed by President Donald Trump, told an industry meeting this week that she was "open to self-assessments" by nuclear plant operators, who are proposing that self-reporting by operators take the place of some NRC inspections.The Trump NRC appointees and industry representatives say changes in oversight are warranted to reflect the industry's overall improved safety records and its financial difficulties, as the operating costs of the country's aging nuclear plants increase and affordable natural gas and solar and wind power gain in the energy market.But the prospect of the Trump administration's regulation-cutting mission reaching the NRC alarms some independent industry watchdogs, who say the words "nuclear safety" and "deregulation" don't go together.For example, "the deregulatory agenda at SEC is a significant concern as well, but it's not a nuclear power plant," said Geoffrey Fettus, a senior attorney for nuclear issues at the Natural Resources Defense Council, referring to the federal government's Securities Exchange Commission."For an industry that is increasingly under financial decline ... to take regulatory authority away from the NRC puts us on a collision course," said Paul Gunter, of the anti-nuclear group Beyond Nuclear. With what? "With a nuclear accident," Gunter said.The industry made its requests for change in a letter delivered by the Nuclear Energy Institute group. A "high-priority" ask is to eliminate press releases about lower-level safety issues at plants — meaning the kind of problems that could trigger more inspections and oversight at a plant but not constitute an emergency.The industry group also asked that the NRC reduce the "burden of radiation-protection and emergency-preparedness inspections."Nuclear plant operators amplified their requests at an annual meeting in the Washington, D.C, area this week.Scaling back disclosure of lower-level problems at plants is "more responsible ... than to put out a headline on the webpage to the world," said Greg Halnon, vice president of regulatory affairs for Ohio-based FirstEnergy Corp., which says its fleet of nuclear and other power plants supplies 6 million customers in the Midwest and Mid-Atlantic.When the NRC makes public the problems found at a plant, utilities get "pretty rapid calls from the press, SEC filings get impacted because of potential financial impact," Halnon said.Requests by utilities for rate increases also can be affected, Halnon said.Trump has said he wants to help both the coal and nuclear power industries. So far, it's the more politically influential coal industry that's gotten significant action on the regulatory rollbacks that it sought from the Environmental Protection Agency and other agencies.In January, Trump appointees to the NRC disappointed environmental groups by voting down a staff proposal that nuclear plants be required to substantially — and expensively — harden themselves against major floods and other natural disasters. The proposal was meant to be a main NRC response to the Fukushima nuclear plant disaster after Japan's 9.0 earthquake and tsunami in 2011.Caputo, who previously worked for nuclear plant operator Exelon Corp, told operators this week her aim was "risk-informed decision-making," concentrating regulatory oversight on high-risk problems."We shouldn't regulate to zero risk," said David Wright, a former South Carolina public-utility commissioner appointed to the NRC board last year."The NRC mission is reasonable assurance of adequate protection — no more, no less," Wright said.Tony Vegel, a Texas-based reactor safety official for the NRC, pushed back when industry executives publicly made their case for fewer NRC inspections."It's difficult to come across as an independent regulator and rely on self-assessment" from plants, Vegel said.The current review, commissioned by the new NRC panel, was looking at the inspections issues and related ones, NRC spokesman Scott Burnell said. Commissioners will decide after receiving the staff recommendations whether to adopt any of them, Burnell said
Oconee Nuclear Station
RA-18-0042
June 19, 2018
Subject: Licensee Event Report 287/2018-001, Revision 00 - Two Main Steam Relief Valve Setpoints Found Out of Tolerance
On 4/20/18, prior to shutdown of Unit 3 for refueling, all 16 of the Unit 3 Main Steam Safety Valves, referred to as Main Steam Relief Valves (MSRV) at Oconee, were tested to satisfy Technical Specification (TS} Surveillance Requirement (SR) 3. 7.1.1. The testing found that the as-found lift pressure for two valves was higher than allowed by SR 3. 7.1.1. The remaining fourteen valves met the SR. Guidance from NU REG 1022 Revision 3 states "the existence of similar discrepancies in multiple valves is an indication that the discrepancies may well have arisen over a period of time and that...the condition existed during plant operation". Thus, the event is considered an operation or condition prohibited by TS and is reportable in accordance with 10 CFR 50.73(a}(2)(i)(B).
The causes of the MSRV test failures were determined to be a combination of setpoint drift and binding of spindle and upper spring washer. Although the lift pressures were. above the acceptance criteria, this condition is bounded by current safety analysis limits and assumptions.
EVALUATION:
BACKGROUND
System Design and lnservice Testing (1ST) Program Information There are two steam lines with eight self-actuated safety valves on each line designed to limit over-pressurization of the Main Steam System [EIIS: SB] to 110% of design pressure under all conditions. The Main Steam Relief Valves (MSRV) [EIIS: RV] actuate to relieve excess steam pressure during plant accidents or events such as Turbine/Reactor trips, rod withdrawal accident at power, etc. These valves have staggered set pressures with nominal values that vary from 1050 psig up to 1104 psig. The allowable tolerance range varies from +3 % to -3%; depending on the specified valve. This acceptance criteria is maintained in the Updated Final Safety Analysis Report (UFSAR), Section 10.3.3, "Main Steam System - Safety Evaluation".
Number of Nominal Set Pressure Allowable As-Found Relief Valves per Line ' (psig) Pressure (psig) ' 1 1050 1019-1060 (+1%/-3%) 1 1065 1033 -1096 (+/-3%) 1 1070 1038 -1102 (+/-3%) 1 1075 1043 -1107 (+/-3%) 2 1080 1048 -1112 (+/-3%) 1 1090 1058-1122 (+/-3%) 1 1104 1071-1137 (+/-3%)
Each Oconee Unit has sixteen (16) Crosby, Model HA/HC-65W valves. All sixteen (16) valves are as-found setpoint tested each refueling outage in accordance with the lnservice Testing (1ST) Program. Each valve is disassembled/inspected and refurbished every ten (10) years. These inspections are staggered such that a sample of the population is inspected each refueling outage. Valve 3MS-5 was last disassembled in 2010. Valve 3MS-8 was last disassembled in 2012.
Related Technical SQecifications (TS) and TS Bases Limiting Condition for Operation (LCO) 3.7.1 states: "Eight MSRVs shall be OPERABLE on each main steam line," and is applicable in Modes 1, 2 and 3. The only Condition in TS 3.7.1 is Condition A, which is entered when one or more MSRV is inoperable. Required Action A.1 requires entry into Mode 3 within 12 hours and, A.2 requires entry into Mode 4 within 18 hours, if any MSRV is inoperable. The only Surveillance Requirement (SR) for this specification is SR 3.7.1.1 which states: 'Verify each MSRV lift setpoint in accordance with the lnservice Test Program."
The TS 3.7.1 bases states: "To be OPERABLE, lift setpoints must remain within limits, specified in the UFSAR."
Plant 0Qerating Conditions At the time of this event, Oconee Unit 3 was in Mode 1 at approximately 83% power (Note: Unit 3 was in an end-of-cycle power coastdown in preparation for a refueling outage). There are no safety systems or components that interact with the MSRV's ability to function. No structures, systems, or components were out of service at the time of this event that contributed to this event.
ReQortability Basis Guidance from NUREG 1022 Revision 3 states "the existence of similar discrepancies in multiple [safety] valves is an indication that the discrepancies may well have arisen over a period of time and that. .. the condition existed during plant operation." Thus, the event is considered an operation or condition prohibited by TS and is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B). '
In 2012, a similar event was reported in LER 287/2012-001-00. The cause of these setpoints being out of tolerance was attributed to setpoint drift. The internal inspection of the valves did not reveal signs of actual binding; however, the potential for binding was identified. Planned actions from the 2012 LER included revision of the appropriate procedures to incorporate the latest manufacturer's criteria for the guide bearing inner diameter (ID) into MSRV scheduled Preventative Maintenance (PM). Additionally, the inspection of the spindle, top spring washer ID, and adjusting bolt ID in their contact area was incorporated into station procedures.
EVENT DESCRIPTION
On April 20, 2018, Oconee Unit 3 was preparing to shutdown for a scheduled refueling outage (03R29). As part of the planned activities, maintenance personnel performed MSRV testing prior to shutdown. All sixteen (16) of the MSRVs were tested. Fourteen (14) MS RVs were found within tolerance but two (2) were out of tolerance. t t t
Specifically, valves 3MS-5 and 3MS-8 as-found set pressure was outside the +3% and +1 % allowable range, respectively. Immediately following each testfailure, the control room was notified, the valves were declared inoperable, and the affected valves were adjusted within the as-left acceptance range. Operations was notified that the valves were back within setpoint tolerance.
The following are the specifics for each valve found out of tolerance:
Valve
3MS-5
3MS-8
CAUSAL FACTORS:
3MS-8
Nominal Setpoint (psig) Limit (psig) As-Found (psig)
1080 1112(+3%) 1129 (+4.5%)
1050 1060 (+1%) 1062 (+1.1%)
Time Found Time Restored
0906 0937 1037 1132
The as-found measured setpoint for 3MS-8 was 1.1 % above nameplate. Since no observable abnormalities were found when the valve was disassembled, the failure itself was attributed to setpoint drift; a historical characteristic with relief valves of this design. While enhancements to maintenance and testing can influence setpoint drift, it is recognized as a phenomenon that can't be totally prevented (IN2006-24).
3MS-5 The as-found measured setpoint for 3MS-5 was 4.5% above nameplate. This is outside normal setpoint drift and abnormalities were found when the valve was disassembled. The 3MS-5 MSRV degradation/failure mechanisms were determined to be binding of spindle and upper spring washer coupled with setpoint drift; which accounted for the total +4.5% setpoint variation.
The binding was due to the spindle being bowed out of tolerance. The guide bearing inner diameter was also found to be smaller than the manufacturer's recommended tolerance. Although no obvious signs of binding were found in this area, it could have affected the set pressure. The inner diameter of the guide bearing would have been inspected and increased during the next scheduled disassembly of 3MS-5 based on corrective actions from the 2012 LER.
During a second test (prior to disassembly), the measured setpoint dropped to +3% of nameplate which further suggested internal valve parts were binding during the first lift. Because the second lift was +3% of nameplate and subsequent lifts following adjustments were consistent, there was also an indication of setpoint drift present with this valve.
CORRECTIVE ACTIONS:
Immediate:
Subsequent:
3MS-5 and 3MS-8, which had an as-found result outside of the allowed tolerance, were promptly adjusted within in tolerance and acceptably retested.
3MS-5 and 3MS-8 were disassembled during the 03R29 refueling outage (Work Orders 20247773 and 20247772, respectively). Both valves were machined to the increased inner diameter of the guide bearing. 3MS-8 was reassembled when no abnormalities were found and set to the as-left setpoint criteria at the end of the unit refueling outage. The spindle and spring assembly were replaced on 3MS-5. The valve was reassembled and set to the as-left setpoint criteria during the unit refueling outage.
None of the above corrective actions are NRC Commitment items. There are no other NRC Commitment items contained in this LER.
SAFETY ANALYSIS
The as-found setpoints of 3MS-1 thru 16 measured on 4/20/2018 were reviewed in aggregate and found to maintain peak secondary pressures that are within safety analysis of record. The feedwater flow capacity for decay heat removal and long-term plant cooldown is determined by the lift pressure of the lowest lifting MSRVs. In this case, 3MS-8 and 3MS-16. Although the lowest lifting valve on the "A" Steam Generator (SG) (3MS-8) was found to be 2 psi too high, this condition is more than offset by the lowest lifting valve on the "B" SG (3MS-16) being 22 psi lower than the design value. These as-found setpoints provide sufficient feedwater flow for decay heat removal and long-term plant cooldown when using either the Emergency Feedwater (EFW), Protected Service Water (PSW), or Standby Shutdown Facility Auxiliary Service Water (SSF ASW) systems. Thus, it is concluded that the impact of this condition on overall plant risk is insignificant and had no impact on public health and safety.
ADDITIONAL INFORMATION
A search of the Oconee Corrective Action Program (CAP;) database for the preceding five (5) year period revealed no similar events that occurred at Oconee Nuclear Station (ONS). Additionally, a review of industry Operating Experience (OE) databases was conducted using applicable keyword searches, i.e., "MSRVs setpoint," etc., to ascertain other reported events.
One related event occurred at Oconee prior to the preceding five (5) year period on April 13, 2012. This LER is discussed in the Background section.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
This event is considered INPO Consolidated Events System (ICES) Reportable.
There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event.
Electric PowerSounds like Curtiss-wright with their safety relief problems. Doesn't look good with all the prestartup problems and now they got to replace the pump.
14 Mar 2019 | 20:31 UTC
Washington
US-designed Chinese nuclear reactor forced to shut by pump defect
Author William Freebairn
Editor Keiron Greenhalgh
Commodity Electric Power
Washington — China's Sanmen-2 nuclear reactor, the third US-designed Westinghouse AP1000 unit to begin operating in the world, has been shut temporarily because of a defect in a reactor coolant pump, which is being replaced, a top Chinese nuclear regulator said Thursday.
A replacement reactor coolant pump has been shipped from the US and is expected to arrive at the Sanmen site in the next several weeks, Shirong Zhou of China's National Nuclear Safety Administration said during the US Nuclear Regulatory Commission's annual conference in Washington.
The unit is the third of four US-designed reactors to operate in China. Chinese companies gained ownership of the technology for the design for domestic use as part of a deal to acquire four units from Westinghouse.
The AP1000 design is a next-generation reactor model that is also being built at Georgia Power's Vogtle plant in the US.
Each AP1000 includes four of the sealed reactor coolant pumps, which have had design and quality problems before.
The AP1000 design at one time had been considered for widespread deployment in China, but delays in construction related to earlier issues with the US-built reactor coolant pumps have reportedly led Chinese decision-makers to favor a domestic reactor design for deployment in larger numbers.
The problem appears to be related to the motor for the giant pump, Zhou said. An initial investigation shows there was leakage around supports for the pump, but a full investigation will have to wait until the defective pump is disassembled and examined after removal, he said.
The reactor coolant pumps, which move coolant around the primary cooling circuit of the reactor, are the largest so-called "canned pumps" to ever be used in a nuclear reactor. The hermetically sealed pumps are designed to operate without leakage and contain a sealed motor system.
The pumps were manufactured by US-based Curtiss-Wright. During construction of the Sanmen and Haiyang units in China, several of the pumps were returned from China to the US for repairs after a defect was discovered that resulted in localized heating of the pumps.
Westinghouse and Curtiss-Wright are engaged in a dispute over responsibility for delivery delays for the pumps in China and the US, Curtiss-Wright has said in financial filings.
With the exception of the pump problem, the overall operating experience of the four AP1000 reactors in China has been good, Zhou said...
During the February 2018 Unit 1 refueling outage, two main steam safety relief valves (SRV) did not pass Technical Specification (TS) Surveillance Requirement 3.4.4.1 and lnservice Testing (IST) Program lift pressure requirements. Both SRVs lifted below their expected lift pressures. On February 27, 2018, SRV 1B21-F013R was required to lift within plus or minus three percent of 1205 psi (i.e., 1205 psi plus or minus 36.1 psi), but lifted at 1167 psi. On February 27, 2018, SRV 1 B21-F013U was required to lift within plus or minus three percent of 1150 psi (i.e., 1150 psi plus or minus 34.5 psi), but lifted at 1109 psi.
Multiple test failures are reportable under 1 O CFR 50. 73(a)(2)(i)(B) as an operation or condition prohibited by the plant's TS. Both SRVs lifted prior to their expected lift pressures, which is conservative regarding maintaining reactor pressure vessel over-pressure limits. Both SRVs were replaced during the outage. A failure analysis was conducted; however, it did not identify a cause for the valves lifting below their expected lift set-points.
LaSalle County Station (LSCS) Unit 1 is a General Electric Boiling Water Reactor with 3546 Megawatts Thermal Rated Core Power.
The main steam safety relief valves (SRVs) are designed to prevent over-pressurization of the reactor pressure vessel (RPV) during transients and abnormal conditions, which protects against a failure of the reactor coolant pressure boundary (RCPB). There are thirteen SRVs installed on the four main steam lines, which discharge near the bottom of the suppression pool to condense the steam through SRV tailpipes that exhaust beneath the suppression pool surface.
CONDITION PRIOR TO EVENT
Unit(s): 1 Date: Reactor Mode(s): 5 Mode(s) Name:
DESCRIPTION OF EVENT
February 27, 2018 Refueling
Time: Power Level:
1520 CST O percent
01
During the February 2018 Unit 1 refueling outage, two main steam safety relief valves (SRV) did not pass Technical Specification (TS) Surveillance Requirement (SR) 3.4.4.1 and lnservice Testing (IST) Program lift pressure requirements. Both SRVs lifted below their expected lift pressures. On February 27, 2018, SRV 1 B21-F013R was required to lift within plus or minus three percent of 1205 psi (i.e., 1205 psi plus or minus 36.1 psi), but lifted at 1167 psi. On February 27, 2018, SRV 1 B21-F013U was required to lift within plus or minus three percent of 1150 psi (i.e., 1150 psi plus or minus 34.5 psi}, but lifted at 1109 psi.
CAUSE OF EVENT
A failure analysis was conducted; however, it did not identify a cause for the valves lifting below their expected lift set-points.
Station operating experience has shown a tendency for a portion of LSCS SRVs to experience minor setpoint drift sufficient to exceed the acceptance criteria of minus three percent over time. A license amendment request (LAA) was submitted to the NRC on February 27, 2018 to revise TS SR 3.4.4.1 to lower the setpoint tolerances for Unit 1 and Unit 2 SRVs. This proposed change would revise the SRV as-found lower tolerances from minus three percent to minus five percent to account for minor SRV setpoint drift in the conservative direction. This proposed change will reduce the unnecessarily restrictive surveillance requirement and will not impact the reliability of the SRVs or adversely impact their ability to perform their safety function. The change will reduce the number of TS SRV surveillance test failures for early lift pressure and preclude the submittal of previously reportable licensee event reports to the NRC due to setpoint drift in the low (conservative) direction...
