Resolution of Generic Safety Issues: Issue 191: Assessment of Debris Accumulation on PWR Sump Performance ( NUREG-0933, Main Report with Supplements 1–35 )
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EXECUTIVE SUMMARY
The issue of potential blockage in the containment sumps was first identified in Unresolved Safety Issue (USI) A-43, "Containment Emergency Sump Performance." It identified a concern for the availability of adequate recirculation cooling water following a loss of coolant accident (LOCA). The issue was declared a USI in January 1979. In October 1985, the staff presented its resolution of USI A-43 to the Commission in SECY-85-349, "Resolution of Unresolved Safety Issue A-43, 'Containment Emergency Sump Performance.'"2220 The staff's technical findings were published in NUREG-0897, "Containment Emergency Sump Performance," dated October 1, 1985.2221 Resolutions items included revision to NUREG 0800, Standard Review Plan (SRP), Section 6.2.2, "Containment Heat Removal Systems.2222 and Regulatory Guide 1.82, "Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident,"2223 to reflect the staff's technical findings reported in NUREG-0897, and Generic Letter (GL) 85-222231 was issued, outlining the safety concerns regarding potential debris blockage and recirculation failure due to inadequate net positive suction head (NPSH). The early history of activities was captured in NUREG/CR-7172, "Knowledge Base Report on Emergency Core Cooling Sump Performance in Operating Light Water Reactors."2224 And NUREG/CR-6808, “Knowledge Base for the Effect of Debris on Pressurized Water Reactor Emergency Core Cooling Sump Performance."2225
The issue for BWRs was resolved in 2001 and documented in "Completion of Staff Reviews of NRC Bulletin 96-03."2227 However, results of research on boiling water reactor (BWR) emergency core cooling system (ECCS) suction strainer blockage identified new phenomena and failure modes that were not considered in the resolution of Issue A-43, "Containment Emergency Sump Performance." Subsequent preliminary parametric calculations were completed in July 2001, indicating the potential for significant debris accumulation in PWRs. In addition, operating experience identified new contributors to debris and possible blockage of pressurized water reactor (PWR) sump strainers, such as degraded or failed containment paint coatings. Thus, a proposed Generic Issue was identified1691 by Office of Nuclear Reactor Regulation (NRR) and called for an expanded research effort to address these new safety concerns and to examine whether the events and new research being conducted for the BWR strainers warranted similar evaluation and/or changes for ensuring the adequacy of PWR recirculation performance. The issue was transferred to NRR for plant specific resolution via letter dated September 28, 2001 “RES Proposed Recommendation for Resolution of GSI-191, ‘Assessment of Debris Accumulation on PWR Sump Performance.’”2228
In July 2019, the Executive Director of NRR sent a memorandum2233 to RES stating that all affected licensees have taken sufficient corrective actions to prevent blockage of the containment sump strainers by installing larger capacity strainers. Therefore, the issue raised by GI-191 is no longer a safety concern and the GI-191 should be closed. Following notification from NRR, the Director of RES issue a memorandum2229 of closure of GI-191.
BACKGROUND
A study was deemed to be required to determine whether PWR ECCS sump strainers are adequate to ensure proper ECCS operation. Based on the existence of an action plan1692 to address the safety concerns, the issue was considered nearly-resolved in September 1996. It was later given a HIGH priority ranking in SECY-98-166, "Summary of Activities Related to Generic Safety Issues."1718
Preliminary calculations were completed in July 2001 indicating the potential for debris accumulation for 69 cases. These 69 cases were representative of, but not identical to, the operating PWR population. The staff’s technical assessment concluded that GSI-191 was a credible concern for the population of domestic PWRs, and that detailed plant-specific evaluations were needed to determine the susceptibility of each U.S.-licensed PWR to ECCS sump blockage. Following the Advisory Committee on Reactor Safeguards (ACRS) agreement with the staff’s technical assessment of the issue in September 2001, RES forwarded the issue to NRR.1910 NRR evaluated the technical assessment, and prepared a Task Action Plan1911 for developing appropriate regulatory guidance and resolution of GSI-191.
- confirm their compliance with 10 CFR 50.46 (b)(5) and other existing applicable regulatory requirements, or (2)
- describe any compensatory measures that have been implemented to reduce the potential risk due to post-accident debris blockage, as evaluations to determine compliance proceed.
All PWR licensees provided a response to NRC Bulletin 2003-01, indicating interim compensatory measures and candidate operator actions that would be implemented. Closure letters were issued to the PWR licensees as these reviews were completed and generic close-out of Bulletin 2003-01 was completed in December 2005. Responses are available to the Bulletin 2003-01 from licensees and Bulletin 2003-01 closure letters.2234
In 2004 the NRC issued Generic Letter (GL) 2004-021913 requiring licensees to respond within 90 days to document the actions planned by the licensee to perform the sump evaluation, and the proposed schedule for completion. All PWR licensees responded to the GL on schedule in September 2005. All PWR licensees committed to modify their containment sump strainer, except for three plants who had modified their containment sump strainers within the last five years. The staff evaluated all 90-day responses to GL 2004-02. In January 2006 issued comments to licensees to be addressed in their final response submittals. Licensees responses and NRC’s comments are available.2235
On September 16, 2005, the NRC issued Information Notice (IN) 2005-261915, "Results of Chemical Effects Head Loss Tests in a Simulated PWR Sump Pool Environment," in order to address concerns regarding the potential for chemical precipitates and corrosion products to significantly block a fiber bed and increase the head loss across an ECCS sump screen, a joint NRC/Industry Integrated Chemical Effects Testing program was started in 2004 and completed in August 2005. Chemical precipitation products were identified during the test program, and follow-up testing and analyses were needed to address the effect on head loss.
On January 26, 2006, the NRC issued IN 2005-26, Supplement 1, "Additional Results of Chemical Effects Tests in a Simulated PWR Sump Pool Environment,"1918 to specifically provide additional information regarding test results related to chemical effects in environments containing dissolved phosphate (e.g., from trisodium phosphate) and dissolved calcium. The NRC conducted additional research in certain areas to support evaluation efforts and provide confirmatory information. These areas include research on chemical effects to determine if the pressurized-water reactor sump pool environment generates byproducts which contribute to sump clogging, research on pump head losses caused by accumulation of containment materials and chemical byproducts, and research to predict the chemical species that may form in these environments. The staff completed reports on the chemical effects on ice condenser containments,1916 and on PWR containments.1917
- the thermodynamic simulation of containment sump pool chemical constituents, to predict the chemical reactions/byproducts in the pools
- the pressure loss across containment sump screens due to fiber insulation, chemical precipitates, and coating debris; and
- a literature survey to summarize the knowledge base to date on the potential contribution of material leached from containment coatings to the chemical products formed in the containment sump pool, after a loss-of-coolant accident.
MILESTONES
In addition to the plant audits, the staff will use inputs from the review of licensee responses to GL 2004-021913 (received in 2008 and 2009) and items identified from regional inspections that were performed using Temporary Instruction TI-2515/166, Pressurized Water Reactor Containment Sump Blcokage."1922 These reviews identified the need for additional information from most licensees in order for the NRC to conclude that the licensees have fully addressed the sump issues.
Another emergent regulatory issue involved some licensees taking credit for certain vendor testing as a basis for assuming reduced generation of debris following a LOCA. The NRC staff reviewed reports describing this testing and developed a number of questions regarding the test methodology. After numerous interactions with the industry on these questions, the NRC staff concluded that the reduced generation assumptions are not substantiated by the testing. The NRC staff informed the industry in March 2010 that it did not accept the testing, to which the industry responded that it would conduct a new testing campaign to address the staff’s concerns, with the intent of still crediting reduced debris generation. The industry completed this testing in 2011, and the results have been reviewed by the staff. In general, the staff found the new test methodology to be acceptable. The updated testing was not submitted formally to the staff so no safety evaluation was completed. If a licensee references the updated testing and methodology in a future submittal, the staff will evaluate the acceptability of its use at that time.
In April 2010, the staff and industry briefed the Commission regarding the status of resolution of GI-191. Representatives from industry summarized their actions to address the issue and suggested that these actions have resolved the safety implications of this GI. The industry representatives further recommended resolution and closure via the application of 10 CFR 50, Appendix A, General Design Criterion 4 (GDC-4). This criterion allows crediting, for certain purposes, the high likelihood that a reactor coolant leak would be detected before a major piping rupture would occur. The NRC staff has not heretofore allowed this credit for resolving sump performance issues and upon further review found that it is not appropriate to credit GDC-4 for the resolution of the GI.
During the Commission brief, the staff acknowledged the industry’s actions to address this issue. However, the staff stated its position that the issue remains of relatively high concern for plants with potentially high fibrous insulation loading that have not demonstrated adequate sump performance to the NRC. Based on the information presented, the Commission directed the staff to provide them with potential approaches for bringing GI-191 to closure. The staff provided this information in SECY-10-0113, "Closure Options for Generic Safety Issue - 191, Assessment of Debris Accumulation on Pressurized Water Reactor Sump Performance," dated August 26, 2010 2014. The Commission issued a staff requirements memorandum (SRM) in December 2010. 2015 2012 with options for the path forward to resolve GI-191, including risk-informed options. The Commission endorsed the staff's proposed options for resolving GI-191 in an SRM dated December 14, 2012 2017. As part of the resolution process, licensees seeking additional time to pursue new testing or new approaches (including risk-informed option) will implement measures to mitigate the potential for debris blockage of the strainer or debris entry into the reactor core.
Based on the interactions with stakeholders and the results of the industry testing, the NRC staff in 2012 developed three options that will be effective ways to resolve GI-191. These options were documented and proposed to the Commission in SECY-12-0093, “Closure Options for Generic Safety Issue 191, Assessment of Debris Accumulation on Pressurized Water Reactor Sump Performance,” dated July 9, 20122027. All options would require licensees to demonstrate compliance with 10 CFR 50.46, “Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors.” The options are summarized as follows:
• Option 1 allows the use of approved models and test methods. Licensees choosing this option will have relatively low fiber plants that can demonstrate that less than 15 grams of fiber per fuel assembly can reach the reactor core
• Option 2 requires implementation of additional mitigative measures until resolution is completed and allows additional time for licensees to resolve issues through further industry testing or use of a risk informed approach. Licensees choosing this option generally have more problematic materials in containment or desire additional margin for their in-vessel debris limits.
o Option 2a Deterministic: Industry to perform more testing and analysis and submit TR WCAP for NRC review and approval (in-vessel only).
o Option 2b Risk Informed: South Texas Project pilot was approved by NRR staff.
• Option 3 involves separating the regulatory treatment of the sump strainer and in vessel effects. The ECCS strainers will be evaluated using currently approved models while in-vessel will be addressed using a risk-informed approach.
The options allowed industry alternative approaches for resolving GI-191. The options are innovative and creative, as well as risk informed and safety conscious. The Commission issued a SRM-SECY-12-00932028 on December 14, 2012, approving all three options for closure of GI-191.
On October 12, 2011, the PWROG released Revision 2 to WCAP-16793-NP, "Evaluation of Long-Term Core Cooling Considering Particulate Fibrous and Chemical Debris in the Recirculating Fluid."2236 On April 8, 2013, the NRC staff issued the SE for Revision 2 to Topical Report WCAP-16793-NP.2237 NRC staff later used this evaluation to issue a partial closure letter to plants opting to use option 2A, stating that only in-vessel effects remain an open issue.
With respect to the Option 2A plants, public meetings were held in spring of 2014 with the PWROG to discuss the testing and analyses being proposed for the new Topical Report WCAP-17788 that was intended to justify higher fiber limits than currently approved by the staff. The Commission directed the staff to develop a risk-informed option to 10 CFR 50.46 long term core cooling requirement with respect to debris. The NRC staff coordinated the development of a risk-informed proposed rulemaking, 10 CFR 50.46c, with the review of the Option 2B plants. Lessons learned from the review of the Option 2B plants will be incorporated into regulatory guidance for implementation of the proposed rule.
To provide open communication on NRC activities associated with GI-191 resolution, public meetings and/or conference calls with NEI and industry representatives continue to be held regularly, as schedules allow and developments regarding issue resolution indicate the need for an interaction. The staff provided regularly scheduled briefings to the ACRS, which provided additional opportunities for communication on technical issues.
Option 1 Plants: All the following Option 1 plants demonstrated that less than 15 grams of fiber per fuel assembly can reach the reactor core, and all have been subsequently closed:
Braidwood, Units 1 and 2 Complete May 19, 20162146
Bryon, Units 1 and 2 Complete May 19, 20162146
Catawba, Units 1 and 2 Complete December 31, 20132147
McGuire, Units 1 and 2 Complete April 24, 20142148
Oconee, Units 1, 2 and 3 Complete August 27, 20142149
Prairie Island, Units 1 and 2 Complete April 10, 20152150
Salem, Units 1 and 2 Complete April 30, 20142151
Sequoyah, Units 1 and 2 Complete November 17, 20142152
Watts Bar, Unit 1 Complete September 17, 20152153
Watts Bar, Unit 2 Complete September 18, 2014 2154
Option 2 Plants:
Option 2A Deterministic Plants: The following is a list of plants opting to use Option 2A:
Comanche Peak Nuclear Power Plants (CPNPP) Units 1 and 2, on May 16, 2013, the licensee, Luminant Power sent the NRC a letter2157 stating that it has selected Option 2a, utilizing a deterministic methodology for both strainer and in-vessel effects. NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Donald C. Cook Nuclear Plant (CNP) Units 1 and 2, on May 15, 2013, the licensee, Indiana Michigan Power Company (I&M), has selected Option 22158 and intends to pursue refinements to evaluation methods and acceptance criteria. I&M will perform the necessary analysis to adopt a higher in-vessel debris limit. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Farley Nuclear Plants, Units 1 and 2, on May 16, 2013, the licensee, Southern Company, sent a letter2159 to the NRC informing the NRC that it has selected Option 2, deterministic approach. NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Ginna, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Shearon Harris Nuclear Power Plant, Unit 1, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Millstone Units 2 and 3, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
North Anna Units 1 and 2, on May 15, 2013, the licensee, Dominion Energy Inc., sent a letter2160 to the NRC informing the NRC that it has selected Option 2 (deterministic) for final resolution of GSI-191 for North Anna Power Station, Units 1 and 2 and intends to pursue refinements to evaluation methods and acceptance criteria associated with downstream in-vessel effects. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Palo Verde Nuclear Generating Station Units 1, 2, and 3, on May 16, 2013, the licensee, Arizona Public Service Company (APS), sent the NRC a letter2161 stating that it has selected Option 2a, utilizing a deterministic methodology for both strainer and in-vessel effects. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Point Beach Units 1 and 2, on May 16, 2013, the licensee, NextEra Energy Point Beach, LLC sent the NRC a letter2162 stating that it selected Option 3. Since that time, the licensee has changed its approach to utilize Option 2.
H.B. Robinson Steam Electric Plant Unit No. 2, on May 14, 2013, the licensee, Duke Energy, sent the NRC a letter2164 stating that it has selected Option 2a, and intends to pursue refinements to evaluation methods and acceptance criteria. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Seabrook, NextEra Energy Seabrook, LLC determined that performing a risk-informed evaluation of the potential for recirculation sump strainer blockage and in-vessel fuel assembly blockage using the STP approach is the preferred approach, in-vessel fuel assembly blockage using the STP approach as the preferred approach.2163
St Lucie Units 1 and 2, on May 15, 2013, the licensee, Florida Power & Light (FPL) sent the NRC a letter2165 stating that it has selected Option 2 Risk Informed method, performing a risk-informed evaluation of the potential for recirculation sump(s) strainer blockage and in-vessel blockage using STP approach.
Surry Units 1 and 2, on May 14, 2013, the licensee, Dominion Energy Inc., sent a letter2166 to the NRC informing the NRC that it has selected Option 2 (deterministic) for final resolution of GSI-191 for Surry Power Station, Units 1 and 2 and intends to pursue refinements to evaluation methods and acceptance criteria associated with downstream in-vessel effects. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Turkey Point Units 3 & 4, Florida Power and Light (FPL) has selected Option 2 Risk Informed, performing a risk-informed evaluation of the potential for recirculation sump(s) strainer blockage and in-vessel blockage using the STP approach.2167
Virgil C. Summer Nuclear Station, Unit 1, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Waterford 3, on May 16, 2013, the licensee, Entergy, sent the NRC a letter stating that it has selected Option 2a, utilizing a deterministic methodology for both strainer and in-vessel effects for Waterford Steam Electric Station, Unit 3. The deterministic resolution of strainer effects has been fully documented in previous submittals to the NRC. The deterministic resolution of the in-vessel effects will be accomplished in accordance with the resolution strategy proposed by the PWROG. The NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue.
Option 2B Risk Informed
South Texas Project (STP) Units 1 and 2, STP was the pilot plant for Option 2B. STP submitted Supplement 1 to Revised STP Pilot Submittal2168 for staff review on November 13, 2013. NRC staff reviewed the submittal and issued a closure letter2185 to STP.
Callaway Plant, Unit 1, the licensee, Ameren Missouri, sent the NRC a letter2182 informing the NRC of its proposed resolution of GL 2004-02 by pursuing Option 2b, "Full Risk-Informed Resolution Path," of SECY-12-0093, noting that the approach being taken for Callaway Plant would utilize the methodology developed by STP. March 31, 2014, the licensee sent a letter2186 with an updated response.
Calvert Cliffs Nuclear Power Plants, Units 1 and 2. The licensee Exelon Generation Company LLC sent the NRC a letter2169 informing the NRC it has selected the deterministic approach of Option 2, with refined chemical effects testing and the risk-informed resolution approach, as identified in SECY-12-0093. Calvert Cliffs has determined that performing refined chemical effects testing may demonstrate the reduced potential for recirculation sump strainer blockage and in-vessel blockage sufficiently to resolve GSI-191 through a deterministic approach. In parallel Calvert Cliffs will also pursue the risk-informed approach partnering with the STP to provide either defense in depth or, as an alternate solution, if the refined chemical effects testing fails to resolve GSI-191 through a deterministic approach.
Wolf Creek Generating Station, Unit 1, Wolf Creek Nuclear Operating Corporation (WCNOC) sent the NRC a letter2183 stating that it has selected Option 2, Risk-Informed Resolution Path. WCNOC has determined that performing a risk-informed evaluation of the potential for recirculation sump strainer blockage and in-vessel blockage, following the STP pilot approach.
Potential Plant Closures
The following is a list of nuclear plants in which the licenses has notified the NRC of intentions to permanently cease power operations. The NRC staff has dispositioned these plants, which have formally submitted a letter of cessation of operations to the NRC, as no longer requiring action in regard to GL 2004-02:
Beaver Valley Units 1 and 2, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue. On April 25, 2018, the licensee sent a letter2172 to the NRC notifying the NRC of intentions to permanently cease operations. The licensee, First Energy, intends to permanently cease power operations of Beaver Valley power station No. 1 by May 31, 2021, and No. 2 by October 31, 2021.
Fort Calhoun Station, Unit 1, On June 24, 2016, the licensee, Omaha Public Power District, provided the NRC a certification2177 of permanent cessation of power operations. On July 22, 2016, the NRC sent a notification2176 to the licensee that no further action in regards to GL 2004-02 will be taken. On October 24, 2016, Fort Calhoun Nuclear Generating Station permanently ceased power operations.
Indian Point Units 2 and 3, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue. The licensee, Entergy, announced that the two operating units at the Indian Point Energy Center will close in 2020-2021.
TMI 1, NRC staff has issued a partial closure letter, stating that only in-vessel effects remain an open issue. The licensee, Exelon, has announced to permanently cease operation of TMI 1 in 2019.
Diablo Canyon Units 1 and 2, the licensee, PG&E announced on June 21, 2016, that it would retire the facility’s two units at Diablo Canyon plant when operating licenses for the units expire in November 2024 and August 2025, respectively.
Palisades, On January 4, 2017, the licensee, Entergy, sent the NRC a letter2173 notifying the NRC of permanent cessation of power operations for Palisades nuclear plant, on October 1, 2018. Hence, on February 22, 2017, the NRC has issued a letter2174 to the licensee of no further actions in regards to GL 2004-02. In September 2017, Entergy, sent NRC letter2175 announcing permanent cessation of operations, supplemented by letter2184 dated October 19, 2017, announcing permanent cessation of operations spring of 2022, no later than May 31, 2022.
Additional References
The NRC has created the following websites to provide stakeholders an overview activities, reports and correspondences associated with this generic issue:
1. "Generic Issues Dashboard," designed to keep the public informed on the status of milestone associated with open issues in the Generic Issues Program: https://www.nrc.gov/about-nrc/regulatory/gen-issues/dashboard.html.
2. "PWR Sump Performance," contains tables, sorted by region, of supplemental responses to Generic Letter 2004-02, Temporary Instruction reports, and other related licensee and NRC correspondences: https://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance.html.
Knowledge Capture - Specific Activities associate with each site:
Below is list of activities associated with this generic issue for each affected licensee, sorted by region:
Region 1
https://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance/generic04-02-correspondence/later/region1.html
Beaver Valley Unit 1
TI-2515/166 Inspection Reports: 1/24/07 and 2/13/08
Licensee Submittals: 2/29/08, 2/29/08, 10/29/08, 03/11/09, 06/30/09, 09/28/10, 05/16/13
NRC Staff letters: 2/18/10
Beaver Valley Unit 2
TI-2515/166 Inspection Reports: 1/24/07 and 2/13/08
Licensee Submittals: 2/29/08, 2/29/08, 10/29/08, 6/30/09, 06/30/09, 09/28/10, 05/16/13
NRC Staff letters: 2/18/10
Calvert Cliffs Unit 1
TI-2515/166 Inspection Reports: 05/08/08, 07/30/08
Licensee Submittals: 02/29/08, 04/22/08, 08/27/08, 09/30/08, 03/02/09, 03/04/09, 10/23/09, 07/23/10, 11/10/10, 12/30/10, 04/28/11, 05/16/13
NRC Staff letters: 12/04/08, 04/12/10
Calver Cliffs Unit 2
TI-2515/166 Inspection Reports: 05/07/07, 07/30/08
Licensee Submittals: 02/29/08, 04/22/08, 08/27/08, 09/30/08, 03/02/09, 03/04/09, 10/23/09, 07/23/10, 11/10/10, 12/30/10, 04/28/11, 05/16/13
NRC Staff letters: 12/04/08, 04/12/10
Indian Point Unit 2
TI-2515/166 Inspection Reports: 08/11/06, 08/13/08
Licensee Submittals: 02/28/08, 11/19/09, 07/27/10, 05/16/13
NRC Staff letters: 07/29/08, 11/19/08, 04/29/10
Indian Point Unit 3
TI-2515/166 Inspection Reports: 05/10/07, 08/07/08
Licensee Submittals: 02/28/08, 12/01/08, 11/19/09, 07/27/10, 05/16/13
NRC Staff letters: 07/29/08, 11/19/08, 04/29/10
Ginna
TI-2515/166 Inspection Reports: 01/31/07, 07/25/08
Licensee Submittals: 02/29/08, 07/25/08, 06/02/09, 04/06/10, 10/26/10, 05/15/13
NRC Staff letters: 01/07/09, 12/04/09
Millstone Unit 2
TI-2515/166 Inspection Reports: 01/30/07, 08/12/08
Licensee Submittals: 02/29/08, 12/18/08 , 03/13/09, 07/08/10, 05/15/13
NRC Staff letters: 12/17/08, 02/04/10, 08/10/10
Millstone Unit 3
TI-2515/166 Inspection Reports: 08/10/07, 08/12/08
Licensee Submittals: 02/29/08, 12/18/08, 03/13/09, 09/16/10, 12/20/10, 05/15/13
NRC Staff letters: 12/17/08, 02/04/10
Salem Unit 1
TI-2515/166 Inspection Reports: 08/14/07, 08/05/08
Licensee Submittals: 02/29/08, 03/31/09, 04/27/12, 04/22/13, 05/10/13, 07/11/13
NRC Staff letters: 08/12/08, 12/17/08, 02/04/10
Salem Unit 2
TI-2515/166 Inspection Reports: 02/01/07, 08/05/08
Licensee Submittals: 02/29/08, 03/31/09, 04/27/12, 04/22/13, 05/10/13, 07/11/13
NRC Staff letters: 08/12/08, 12/17/08, 02/04/10
Seabrook Unit 1
TI-2515/166 Inspection Reports: 08/01/08
Licensee Submittals: 02/28/08, 08/04/08, 03/03/12, 05/15/13
NRC Staff letters: 08/14/09
Three Mile Island Unit 1
TI-2515/166 Inspection Reports: 02/11/08, 04/25/08
Licensee Submittals: 12/28/07, 11/10/08, 02/12/09, 11/09/09, 05/16/13
NRC Staff letters: 01/30/08, 08/12/08, 07/23/09
Region 2
https://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance/generic04-02-correspondence/later/region2.html
Catawba Unit 1
TI-2515/166 Inspection Reports: 7/30/08
Licensee Submittals: 02/29/08, 04/30/08, 02/17/09, 07/28/09, 09/30/10, 08/13/12, 05/13/13, 07/31/13
NRC Staff letters: 11/21/08
Catawba Unit 2
TI-2515/166 Inspection Reports: 1/31/08
Licensee Submittals: 02/29/08, 04/30/08, 02/17/09, 07/28/09, 09/30/10, 08/13/12, 05/13/13, 07/31/13
NRC Staff letters: 11/21/08
Crystal River Unit 3
TI-2515/166 Inspection Reports: 1/29/08
Licensee Submittals: 02/29/08, 08/04/08, 02/26/09, 03/22/10, 06/05/13
NRC Staff letters: 08/07/08, 12/02/08, 10/02/09
Farley Unit 1
TI-2515/166 Inspection Reports: 01/30/08, 07/30/08
Licensee Submittals: 02/28/08, 04/29/08, 07/27/09, 03/30/10, 05/16/13
NRC Staff letters:
Farley Unit 2
TI-2515/166 Inspection Reports: 07/30/07, 01/30/08, 07/30/08
Licensee Submittals: 02/28/08, 04/29/08, 12/17/08, 07/27/09, 03/30/10, 05/16/13
NRC Staff letters: 03/09/09, 05/05/10
McGuire Unit 1
TI-2515/166 Inspection Reports: 07/24/07, 07/24/08
Licensee Submittals: 02/28/08, 04/30/08, 09/30/10, 07/02/12 , 05/08/13, 07/31/13
NRC Staff letters: 11/18/08
McGuire Unit 2
TI-2515/166 Inspection Reports: 07/24/08
Licensee Submittals: 02/28/08, 04/30/08, 09/30/10, 07/02/12, 05/08/13, 07/31/13
NRC Staff letters: 11/18/08
North Anna Unit 1
TI-2515/166 Inspection Reports: 01/31/08, 08/25/08
Licensee Submittals: 02/29/08, 02/27/09, 04/27/11, 05/15/13
NRC Staff letters: 02/10/09, 05/28/09
North Anna Unit 2
TI-2515/166 Inspection Reports: 07/31/07, 08/25/08
Licensee Submittals: 02/29/08, 02/27/09, 04/27/11, 05/15/13
NRC Staff letters: 02/10/09, 05/28/09
Oconee Unit 1
TI-2515/166 Inspection Reports: 01/30/07, 04/30/08
Licensee Submittals: 02/29/08, 12/22/08, 07/16/09, 05/15/13, 07/31/13, 02/27/14
NRC Staff letters: 7/1/08
Oconee Unit 2
TI-2515/166 Inspection Reports: 01/30/07, 04/30/08
Licensee Submittals: 02/29/08, 12/22/08, 07/16/09, 05/15/13, 07/31/13, 02/27/14
NRC Staff letters: 7/1/08
Oconee Unit 3
TI-2515/166 Inspection Reports: 07/28/06, 04/30/08
Licensee Submittals: 02/29/08, 12/22/08, 07/16/09, 05/15/13, 07/31/13, 02/27/14
NRC Staff letters: 7/1/08
Robinson
TI-2515/166 Inspection Reports:7/27/07
Licensee Submittals: 03/07/08, 12/17/08, 03/30/10, 10/08/10, 05/14/13
NRC Staff letters: 07/25/08, 12/03/09, 06/09/10
Sequoyah Unit 1
TI-2515/166 Inspection Reports: 1/30/08
Licensee Submittals: 02/29/08, 02/23/09, 04/01/10, 06/02/11, 05/16/13
NRC Staff letters:
Sequoyah Unit 2
TI-2515/166 Inspection Reports: 2/22/07, 1/30/08
Licensee Submittals: 02/29/08, 02/23/09, 04/01/10, 06/02/11, 05/16/13
NRC Staff letters: 11/25/08, 10/14/09
Shearon Harris
TI-2515/166 Inspection Reports: 1/29/08
Licensee Submittals: 02/28/08, 03/28/08, 01/27/09, 04/27/10, 01/31/11, 05/16/13
NRC Staff letters: 09/29/08, 12/30/09, 06/18/10
St. Lucie Unit 1
TI-2515/166 Inspection Reports: 07/19/07, 07/17/08,
Licensee Submittals: 02/27/08, 06/30/08, 04/22/09, 07/30/09, 07/30/09, 03/03/12, 05/15/13
NRC Staff letters: 09/17/08, 01/22/09, 04/09/10
St. Lucie Unit 2
TI-2515/166 Inspection Reports:2/1/08
Licensee Submittals: 02/27/08, 06/30/08, 04/16/09, 03/03/12, 05/15/13,
NRC Staff letters: 01/16/09, 09/22/10
Summer
TI-2515/166 Inspection Reports: 1/25/07
Licensee Submittals: 02/29/08, 09/09/08, 11/29/09, 12/17/10, 05/16/13
NRC Staff letters: 02/03/09, 05/17/10
Surry Unit 1
TI-2515/166 Inspection Reports: 01/31/08
Licensee Submittals: 02/27/08, 06/30/08, 04/22/09, 07/30/09, 07/30/09, 03/03/12, 05/15/13
NRC Staff letters: 6/18/09
Surry Unit 2
TI-2515/166 Inspection Reports: 01/31/08, 07/30/08
Licensee Submittals: 02/29/08, 02/27/09, 12/17/09, 04/13/10, 05/14/13
NRC Staff letters: 6/18/09
Turkey Point Unit 3
TI-2515/166 Inspection Reports: 10/30/07, 07/30/08
Licensee Submittals: 02/28/08, 03/28/08, 06/30/08, 10/31/08, 03/19/09, 07/30/09, 09/20/10, 03/03/12, 05/09/13
NRC Staff letters: 12/19/08, 08/25/09, 02/18/10
Turkey Point Unit 4
TI-2515/166 Inspection Reports: 07/30/08
Licensee Submittals: 02/28/08, 04/28/08, 08/11/08, 03/19/09, 09/17/10, 04/20/11, 03/03/12, 05/09/13
NRC Staff letters: 12/19/08, 08/25/09, 02/18/10
Vogtle Unit 1
TI-2515/166 Inspection Reports: 01/22/07, 07/31/08
Licensee Submittals: 02/28/08, 05/21/08, 07/31/08, 08/22/08, 11/19/09, 05/16/13
NRC Staff letters: 09/17/08, 12/02/08
Vogtle Unit 2
TI-2515/166 Inspection Reports: 07/30/07, 07/31/08
Licensee Submittals: 02/28/08, 05/21/08, 07/31/08, 08/22/08, 11/19/09, 05/16/13
NRC Staff letters: 09/17/08, 12/02/08
Watts Bar Unit 1
TI-2515/166 Inspection Reports: 01/29/07, 08/07/08
Licensee Submittals: 03/31/08, 03/03/09, 04/01/10, 08/15/11, 05/16/13
NRC Staff letters: 12/03/08, 09/29/09
Watts Bar Unit 2:
Region 3
https://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance/generic04-02-correspondence/later/region3.html
Braidwood Unit 1
TI-2515/166 Inspection Reports: 2/1/08
Licensee Submittals: 12/31/07, 07/15/08, 09/19/08, 05/29/09, 05/14/13
NRC Staff letters: 07/24/08, 04/15/09
Braidwood Unit 2
TI-2515/166 Inspection Reports: 2/13/07
Licensee Submittals: 12/31/07, 07/15/08, 09/19/08, 05/29/09, 05/14/13
NRC Staff letters: 07/24/08, 04/15/09
Bryon Unit 1
TI-2515/166 Inspection Reports: 11/08/06, 08/08/07, 03/13/08
Licensee Submittals: 12/31/07, 07/15/08, 09/19/08, 05/29/09, 05/14/13
NRC Staff letters: 07/24/08, 04/15/09
Bryon Unit 2
TI-2515/166 Inspection Reports: 08/08/07, 03/13/08
Licensee Submittals: 12/31/07, 07/15/08, 09/19/08, 05/29/09, 05/14/13
NRC Staff letters: 07/24/08, 04/15/09
Davis Besse Unit 1
TI-2515/166 Inspection Reports: 7/21/08
Licensee Submittals: 02/28/08, 04/30/10, 05/15/13
NRC Staff letters: 7/10/08
DC Cook Unit 1
TI-2515/166 Inspection Reports: 02/12/07, 08/13/08
Licensee Submittals: 02/29/08, 08/29/08, 05/26/10, 05/19/11, 05/15/13
NRC Staff letters: 06/18/09, 08/31/09, 07/27/10
DC Cook Unit 2
TI-2515/166 Inspection Reports: 1/24/08
Licensee Submittals: 02/29/08, 08/29/08, 05/26/10, 05/19/11, 05/15/13
NRC Staff letters: 06/18/09, 08/31/09, 07/27/10
Kewaunee
TI-2515/166 Inspection Reports: 01/26/07, 01/30/07, 05/14/08, 05/16/08
Licensee Submittals: 02/29/08, 12/18/08, 09/07/10, 05/13/13
NRC Staff letters: 08/14/09, 10/14/09
Palisades
TI-2515/166 Inspection Reports: 01/30/08, 08/14/08
Licensee Submittals: 02/27/08, 03/20/09, 06/30/09, 05/15/13
NRC Staff letters: 12/24/08, 5/13/09, 03/08/10
Point Beach Unit 1
TI-2515/166 Inspection Reports: 08/08/07, 01/22/08, 08/11/08
Licensee Submittals: 02/29/08, 06/09/08, 04/07/09, 07/31/09, 02/04/11, 03/03/12, 05/16/13
NRC Staff letters: 01/07/09, 06/23/09, 07/01/10, 03/03/10
Point Beach Unit 2
TI-2515/166 Inspection Reports: 01/25/07, 01/22/08, 08/11/08
Licensee Submittals: 02/29/08, 06/09/08, 04/07/09, 07/31/09, 02/04/11, 03/03/12, 05/16/13
NRC Staff letters: 01/07/09, 06/23/09, 07/01/10, 03/03/10
Praire Island Unit 1
TI-2515/166 Inspection Reports: 08/14/06, 02/05/07, 08/14/08
Licensee Submittals: 02/28/08, 03/31/08, 05/09/13
NRC Staff letters: 05/18/07, 06/01/09
Praire Island Unit 2
TI-2515/166 Inspection Reports: 02/05/07, 08/14/08
Licensee Submittals: 02/28/08, 03/31/08, 05/09/13
NRC Staff letters: 6/1/09
Region 4
https://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance/generic04-02-correspondence/later/region4.html
ANO Unit 1
TI-2515/166 Inspection Reports: 08/03/07
Licensee Submittals: 02/28/08, 09/15/08, 09/24/09, 04/08/10, 09/29/10, 12/21/11, 03/20/13, 05/16/13
NRC Staff letters: 05/21/09, 01/26/10
ANO Unit 2
TI-2515/166 Inspection Reports: 02/14/07
Licensee Submittals: 02/28/08, 09/15/08, 09/24/09, 04/08/10, 09/29/10
NRC Staff letters: 05/21/09, 01/26/10
Callaway
TI-2515/166 Inspection Reports: 08/02/07, 08/05/08
Licensee Submittals: 02/29/08, 11/04/09, 12/10/09, 05/16/13, 10/31/13, 03/31/14
NRC Staff letters: 07/31/09, 08/27/09, 09/23/13
Comanche Peak Unit 1
TI-2515/166 Inspection Reports: 07/24/07, 08/04/08
Licensee Submittals: 02/29/08, 08/28/08, 11/26/08, 10/13/09, 09/10/09, 10/12/09, 05/16/13
NRC Staff letters: 07/15/09, 04/19/10, 09/30/13
Comanche Peak Unit 2
TI-2515/166 Inspection Reports: 02/08/07, 08/04/08
Licensee Submittals: 02/29/08, 08/28/08, 11/26/08, 10/13/09, 09/10/09, 10/12/09, 05/16/13
NRC Staff letters: 07/15/09, 04/19/10, 09/30/13
Diablo Canyon Unit 1
TI-2515/166 Inspection Reports: 08/01/07, 05/01/08
Licensee Submittals: 02/01/08, 07/10/08, 11/03/08, 06/16/09, 05/14/13
NRC Staff letters: 08/01/08, 10/15/09
Diablo Canyon Unit 2
TI-2515/166 Inspection Reports: 5/1/08
Licensee Submittals: 02/01/08, 07/10/08, 11/03/08, 05/14/13
NRC Staff letters: 08/01/08, 10/15/09
Fort Calhoun
TI-2515/166 Inspection Reports: 8/12/08
Licensee Submittals: 10/16/08, 02/29/08, 05/15/13
NRC Staff letters: 07/28/08, 02/12/10
Palo Verde Unit 1
TI-2515/166 Inspection Reports: 07/20/07, 02/04/08
Licensee Submittals: 02/29/08, 03/13/09, 05/16/13, 08/30/13
NRC Staff letters: 12/16/08, 01/07/10
Palo Verde Unit 2
TI-2515/166 Inspection Reports: 8/14/08
Licensee Submittals: 02/29/08, 03/13/09, 05/16/13, 08/30/13
NRC Staff letters: 12/16/08, 01/07/10
Palo Verde Unit 3
TI-2515/166 Inspection Reports: 2/4/08
Licensee Submittals: 02/29/08, 03/13/09, 05/16/13, 08/30/13
NRC Staff letters: 12/16/08, 01/07/10
San Onofre Unit 2
TI-2515/166 Inspection Reports: 02/13/08, 08/08/08
Licensee Submittals: 02/27/08, 10/30/08, 02/23/09, 11/12/09, 05/15/13
NRC Staff letters: 09/17/08, 11/26/08, 03/12/10
San Onofre Unit 3
TI-2515/166 Inspection Reports: 8/8/08
Licensee Submittals: 02/27/08, 10/30/08, 02/23/09, 11/12/09, 05/15/13
NRC Staff letters: 09/17/08, 11/26/08, 03/12/10
South Texas Unit 1
TI-2515/166 Inspection Reports: 8/17/07, 8/12/08
Licensee Submittals: 02/29/08, 12/11/08, 12/09/10, 06/19/13
NRC Staff letters: 12/23/09
South Texas Unit 2
TI-2515/166 Inspection Reports: 8/17/07, 8/12/08
Licensee Submittals: 02/29/08, 12/11/08, 12/09/10, 06/19/13
NRC Staff letters: 12/23/09
Waterford Unit 3
TI-2515/166 Inspection Reports: 2/13/07
Licensee Submittals: 02/29/08, 10/23/08, 06/17/10, 11/23/10, 05/16/13
NRC Staff letters: 01/28/08, 09/22/09, 06/01/10
Wolf Creek
TI-2515/166 Inspection Reports: 2/6/07
Licensee Submittals: 01/29/08, 11/20/09, 08/27/09
NRC Staff letters: 7/31/09
REFERENCES
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