ML24200A163
| ML24200A163 | |
| Person / Time | |
|---|---|
| Site: | Rhode Island Atomic Energy Commission |
| Issue date: | 07/18/2024 |
| From: | Goodwin C State of RI, Atomic Energy Comm |
| To: | Patrick Boyle Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML24200A163 (1) | |
Text
July 18, 2024 STATE OF RHODE ISLAND Rhode Island Atomic Energy Commission 16 Reactor Road Narragansett, RI 02882-1165 Telephone# 401-874-2600 Docket No. 50-193 Document Control Desk U.S. Nuclear Regulatory Commission (NRC) 11555 Rockville Pike Rockville, Maryland 20852 Attn: Mr. Patrick Boyle, Project Manager
Dear Mr. Boyle:
This letter and the enclosures constitute the annual report required by the RINSC Technical Specifications (Section 6.7.1). Enclosure 1 provides reactor operating statistics. Enclosure 2 provides information pertaining to unscheduled reactor shutdowns or scrams. Enclosure 3 discusses maintenance operations performed during the reporting period. Enclosure 4 describes changes to the facility carried out under the conditions of Section 50.59 of Chapter 10 of the Code of Federal Regulations. Lastly, Enclosure 5 summarizes the radiological controls information. If there are any questions regarding this information, please call me at 401-874-9437.
Sincerely,
~
Dr. Cameron Goodwin Director, RINSC Enclosures (5)
Copy to:
Mr. Craig Bassett, USNRC Dr. John J. Breen, Chairman, NRSC Dr. Clinton Chichester, Chairman, RIAEC Dr. Nancy Breen, RIAEC Mr. Howard Chun, RIAEC Dr. Yana K. Reshetnyak, RIAEC Reactor Operating Statistics Technical Specification Section 6.7.1.1 Month Year Operating MWHof Hours Operation July 2023 11.83 13.52 August 2023 14.20 9.36 September 2023 23.33 16.67 October 2023 24.63 33.60 November 2023 30.45 36.36 December 2023 13.58 14.75 January 2024 16.28 15.55 February 2024 34.48 39.06 March 2024 36.27 40.57 April 2024 42.90 36.54 May 2024 23.32 22.89 June 2024 42.20 41.65 Total FY2024 313.47 320.52 MWH or 13.36 MWD Total Energy Output Since Initial Criticality 69,312.81 MWH or 2888.03 MWD
ENCLOSURE 2 UNSCHEDULED SHUTDOWNS OR SCRAMS Technical Specification Section 6.7.1.2 Page 1 of 1 The following is a list of the unscheduled shutdowns or scrams that occurred during the 2023-2024 reporting period:
Log book 67 Run# 9896 - Scram cause unidentified/ spurious Log book 68 Run# 9941 - Instrument noise Run # 9968 - Watchdog timer scram Run# 9972 - Spurious scram/ Power transient Run# 9974 - Scram while manipulating power selector switch (Inst. noise)
Run# 9982 - Instrument noise Run# 9982 - Instrument noise (2nd occurrence)
Run# 9989 - Instrument noise
ENCLOSURE 3 MAINTENANCE OPERATIONS Technical Specification 6.7.1.3 requires a listing of the major maintenance operations performed in the 2023-2024 reporting period including their impact upon the safe operation of the reactor and the reasons for the corrective maintenance.
Primary Loop #2 Flow - Differential Pressure (D/P) Detector failed and was replaced with a matching specification Foxboro D/P Detector.
ENCLOSURE 4 FACILITY CHANGES - 1 0CFRS0.59 REVIEW Technical Specification 6.7.1.4 requires that we provide a listing and description of any 10 CFR 50.59 evaluations conducted during the 2023-2024 reporting period.
A 10 CFR 50.59 evaluation was performed on the following facility changes:
New Facility Emergency Generator.
Shim Safety Magnet Power Supply Replacement.
Both 50.59 reviews are attached. Note the Magnet Power Supply 50.59 review was written during the last reporting period, it was not completed and approved by the Safety Committee until August of 2023.
ENCLOSURE 5 RADIOLOGICAL CONTROLS
- 1.
Environmental Surveys outside the Facility - Technical Specification 6.7.1.6 Quarterly TLD1 badges are deployed outside the reactor building in three separate locations. The quarterly doses in units of mrem are shown in the table below. The second quarter of year 2024 reports are not available yet due to the vendor's reports were not ready.
LOCATION 2nd QTR 3rd QTR 4th QTR 1st QTR 2nd QTR 2023 2023 2023 2024 2024 Northeast Wall 13 105 28 7
No data Demineralizer Door 29 22 48 46 No data Heat Exchanger Door 46 20 28 29 No data The general public does not frequent these locations and therefore occupancy factors may be used to approximate annual dose. The allowable annual external dose for whole body must be below 100 mrem per year. Assuming that the maximum time that a member of the general public would be present in one of these locations is 10 minutes per day, an occupancy factor of 0.025 can be used to obtain the annual dose that would be received by a member of the general public, in any of these areas.
The annual dose at the Northeast Wall, Demineralizer and Heat Exchanger Doors is dependent on the operations schedule of the reactor. Ignoring the fact that the dose rate is not present 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per day, and applying the occupancy factor of 0.0252, the annual dose that would be receive by an individual in the demineralizer room would be 3.625 mrem. The dose received at the Heat Exchanger Door would be 3.075 mrem.
The annual dose received at the Northeast wall would be 3.825 mrem. The variations from quarter to quarter and from previous reports are also due in part to movements of items within the reactor building during the fiscal year and varying use of the different irradiation facilities.
- 2.
Annual Exposures Exceeding 500 mrem for facility members, 100 mrem for non-staff members or 10 mrem for members of the general public - Technical Specification 6.7.1.7 Two facility member exposures were greater than 500 mrems due to handling of experiment samples. One member was over the reportable dose due to abnormality and was reported. During the inspection, the inspector was reviewed and interviewed the member and the inspector agreed that it was abnormality.
1Thermoluminescent Dosimeter; Mirian Technology reads the dosimeters at minimum of 1 mrem.
2 Occupancy factor of 0.025 was used, from NCRP 147 for Outdoors, unattended parking lots, attics, stairways, unattended elevators, janitor's closets.
- 3.
Radioactive Effluents - Technical Specification 6. 7.1.5 A. Individual gaseous effluent concentrations for each reactor operation are recorded on the Monthly Information Sheets (Form NSC-78). The concentration of radioactive materials in the effluent released from the facility exhaust stacks shall not exceed 1 E+05 times concentrations specified in 1 0CFR20, Appendix B, Table 2, when averaged over time periods permitted by 1 0CFR20. 3 Gamma spectroscopy of stack gas samples has shown that the principal gaseous effluent is Argon-41. The maximum concentration for this principle contaminant permitted under Technical Specifications is 1 E-8 µCi/cc x1 E+5 = 1 E-3 µCi/cc.
Average concentrations released during the year were 4.31 E-5 µCi/cc and 0.0431 of the limit.
The total Argon-41 release during the reporting period was 69.67 curies. The calculated effective dose equivalent for this release is 1.4 mrem/year (COMPLY Code). The Comply Code report is attached.
B. Liquid effluent concentrations released to the environment are documented on the Sewer Discharge Report (NSC-52). Each release was approved prior to discharge with its pH being within the acceptable range and with the sum of the fractions of the respective radioisotopes per month being below the discharge limit of 1. For the reporting period, the total volume of discharge was 6.74E6 ml. The isotopes and their relative activities discharged are given below.
Radioisotope Total Activity Discharged (microcuries)
H-3 12297.83 C-14 48.66 Sb-124 0.84 1-124 1.4 Pb-214 53.9 Bi-214 49.35 K-40 0.0 3 Technical Specifications, Section 3.7.2.
11/12/13 10 CPR 50.59 Review NSC - 51 Date: 10/11/23 Approved By:
Michael J. Davis
Title:
Emergency Generator Replacement As an attachment to this form, provide a written description of the proposed modification, the purpose for making the modification, and a justification for the answer to each of the following questions:
- 1.
Does the change require a change to the Technical Specifications of the R-95 License?
Y The R-95 Technical Specification 3.6 requires that an emergency power system be operable when the reactor is operating, and during a number of other scenarios. Technical Specification 4.6.3 requires that during these scenarios, the available fuel for the generator shall be at least 50% of full capacity. The basis for Technical Specification 4.6.3 indicates that the purpose of making sure that the available fuel is at least 50% of full capacity is to ensure that the generator could run at full load for approximately 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The original emergency generator was a 15 kW, 18.75 kVA, 120/208 3 Phase power source. The new generator is a higher capacity 22 kW, 27.5 kVA, 120/208 3 Phase power source. Consequently, it has more power capacity than the generator that it is replacing.
The "231011 Emergency Generator Operation Time" analysis that is attached shows that the basis for Technical Specification 4.6.3 will be met because when the generator is operating at full load, it would run for approximately 34 hours3.935185e-4 days <br />0.00944 hours <br />5.621693e-5 weeks <br />1.2937e-5 months <br /> on 50% of the full fuel capacity.
- 2.
Could the change result in more than a minimal increase in the frequency of occurrence of an accident that has been previously evaluated in the SAR?
Y N
The emergency generator is used for maintaining confinement by powering the confinement ventilation system in the event of a power failure. Technical Specification 4.6.1 requires that the generator be operable during any of the scenarios that could result in a fission product release. Technical Specification 4.6.2 requires that the generator be tested under full load conditions at least quarterly. These specifications ensure that the generator will be able to perform its intended function if needed. Replacing the old generator with a new one will not increase the frequency of the occurrence of an accident.
- 3.
Could the change result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component that is important to safety and evaluated in the SAR?
Y
As discussed in question 2, the generator is tested to ensure that it will be able to perform its intended function when needed. Replacing the old generator with a new generator is likely to reduce the probability that it will fail.
- 4.
Could the change result in more than a minimal increase in the consequences of an accident that is evaluated in the SAR?
y The emergency power system is used to mitigate accidents that involve a radioactive particulate or gaseous release. Replacing the old generator with a new, higher capacity generator will not lead to an increase in the consequences of this type of accident.
- 5.
Could the change result in more than a minimal increase in the consequences of a malfunction of a structure, system, or component that is important to safety and evaluated in the SAR?
y The emergency power system is important to safety and evaluated in the SAR.
Replacing the old system with a new, higher capacity system will have no impact on the consequences of a power system failure, but it will likely reduce the probability of a system failure.
- 6.
Could the change result in creating the possibility of an accident of a different type than the accidents that have been evaluated in the SAR?
y N
Replacing the old generator with a new generator will not create the possibility of a different type of accident than the ones that have been evaluated in the SAR.
- 7.
Could the change result in creating the possibility for a malfunction of a structure, system, or component that is important to safety, with a different result than predicted in the SAR?
y Replacing the old generator with a new generator will not create the possibility for a malfunction of a structure, system, or component that is important to safety, with a different result than predicted in the SAR.
- 8.
Could the change result in a design basis limit for a fission product barrier as described in the SAR being altered or exceeded?
y Replacing the old generator with a new generator will not result in a design basis limit for a fission product barrier as described in the SAR being altered or exceeded.
- 9.
Could the change result in a departure from a method of evaluation used in the SAR for establishing the design bases for the facility?
y
Replacing the old generator with a new generator will not result in a departure from a method of evaluation used in the SAR for establishing the design bases for the facility.
If the answer to any of these questions is yes, then an NRC approved license amendment pursuant to 10 CFR 50.90 shall be obtained before the modification is implemented.
11/12/13 Date:
5/5/23
Title:
10 CFR 50.59 Review Approved By:
Michael J. Davis 2023 Shim Safety Magnet Current Supply Replacement NSC - 51 As an attachment to this form, provide a written description of the proposed modification, the purpose for making the modification, and a justification for the answer to each of the following questions:
- 1.
Does the change require a change to the Technical Specifications of the R-95 License?
Y The RINSC Technical Specifications provide:
- Safety Limits
- Limiting Safety System Settings
- Limiting Conditions for Operation
- Surveillance Requirements
- Design Features
- Administrative Controls Of these, the only section of the Technical Specifications that could potentially be affected is the Design Feature section. The shim safety magnets are part of the design. However, the specifications do not indicate how the shim safety magnets are supplied with current, or how scram trips are configured.
The mechanisms for cutting off the current to the shim safety magnets have not changed. The existing system biases down a transistor in each of the magnet current supplies when an over power or fast period trip setting is reached through a trip input. The remaining system trips are daisy chained. If a trip occurs, input power to the current amplifiers is shut off so that there is no current supply to the magnets. This is achieved by opening a scram relay, through which input power is supplied the current supplies.
The new system cuts off an FET when any scram trip occurs though a trip input.
For trips that are not related to over power or fast period, the original scram daisy chain and scram relay are still in place.
The existing system has two magnet current supplies, each of which provides current to two of the four shim safety magnets in parallel. Consequently, if one of them were to fail in such a way that magnet current was not cut off during a scram condition, two magnets would still remain energized.
With the new system, additional redundancy is provided because each magnet has its own independent current supply. If one of these supplies fails, only one magnet would be affected.
The Shim Safety Magnet Current Supply Overview provides the details on how the new system works:
- Section 8 shows how the scram signals are fed from the scram logic to the magnet current supplies through optically coupled isolators.
- Sections 9 and 10 provide details about how the scram logic for each of the current supplies work.
- Sections 11 through 19 show how the rod drop timer circuit works.
This change does not affect any of the technical current specifications. All of the reactor trips that are required by the Technical Specifications remain in place, along with the original trip sensors. The new current supplies replace the vintage tube based technology of the previous system, with a solid state based system for supplying current to the magnets.
- 2.
Could the change result in more than a minimal increase in the frequency of occurrence of an accident that has been previously evaluated in the SAR Y
The SAR evaluates the following accidents:
- Maximum Hypothetical Accident - Fuel Failure Accident
- Reactivity Insertion Accident
- Maximum Credible Accident - Loss of Coolant Accident
- Loss of Coolant Flow Accident
- Mishandling or Malfunction of Fuel
- Experimental Malfunction
- Loss of Normal Electrical Power
- External Events
- Mishandling or Malfunction of Equipment Of these accident scenarios, the magnet current supplies are only associated with the insertion of reactivity, and the loss of electrical power.
The replacement of the current supplies does not increase the likelihood of a reactivity insertion accident because that accident would be stopped by one of the existing over power or fast period scrams that come from the two wide range monitors, and the neutron flux monitor. These trips have not changed. The new current supplies are designed to cut the current to the shim safety magnets in such a way as to ensure that the control blades will be fully inserted into the core within one second IA W Technical Specification 3.2.2. Furthermore, unlike the existing system, each of the current supplies in the new system are completely independent of each other. This additional redundancy decreases the probability that a failure of a current supply could prevent the safety system from stopping a reactivity transient.
The amplifiers that are presently in use cannot cause a loss of normal electrical power. If there was a loss of electrical power, the supply of current to the shim safety magnets would be interrupted and the reactor would scram.
- 3.
Could the change result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component that is important to safety and evaluated in the SAR?
Y The new magnet power system simply provides current to the shim safety magnets, provided that the instrument has power, and that a scram condition does not exist. As with the previous system, there is a key lockout that prevents the instrument from receiving power unless the master switch is unlocked and in the "On" position. This is unchanged. The new system provides the same function as the previous system. It does not interact with any structures, systems, or components in any different way than the previous system did. Consequently, this change cannot increase the likelihood of a malfunction that is important to safety and evaluated in the SAR.
- 4.
Could the change result in more than a minimal increase in the consequences of an accident that is evaluated in the SAR?
Y The Magnet Current Instrumentation has no effect on the consequences of an accident that is evaluated in the SAR. This instrument is simply a source of current for the shim safety magnets.
- 5.
Could the change result in more than a minimal increase in the consequences of a malfunction of a structure, system, or component that is important to safety and evaluated in the SAR?
Y The shim safety current supplies do not have any effect on structures or components. They are related to the scram system, but the consequence of the failure of the new system is identical to the consequence of the failure of the old system. Therefore, this change does not result in an increase in the consequence of a malfunction of the system.
- 6.
Could the change result in creating the possibility of an accident of a different type than the accidents that have been evaluated in the SAR?
Y iN This new instrument does not affect any systems other than the one that it is replacing. It provides the same function that the previous system provided, and is not capable of creating a new kind of accident.
- 7.
Could the change result in creating the possibility for a malfunction of a structure, system, or component that is important to safety, with a different result than predicted in the SAR?
Y
If the new instrument were to fail such that a control rod did not drop when a scram condition occurred, the result would be no different than if this had happened with the previous instrumentation.
The previous magnet current supplies each provided current to two shim safety magnets. As a result, a failure of the previous system could potentially cause two shim safety blades to fail to drop. The new system has independent current supplies for each shim of the safety magnets. Consequently, a failure of the new system would only affect one of the four shim safety blades.
- 8.
Could the change result in a design basis limit for a fission product barrier as described in the SAR being altered or exceeded?
Y N
This instrument has no effect on the fission product barrier.
- 9.
Could the change result in a departure from a method of evaluation used in the SAR for establishing the design bases for the facility?
Y The design basis accident for the facility is a fuel failure accident. The only impact that a new magnet current supply system could potentially have on the safety analysis for that accident would be if the new system failed to release the shim safety blades within one second of the initiation of a scram. The one second drop time was used in the reactivity insertion accident analysis. The new system is designed such that the shim safety blades will still be fully inserted into the core within one second after a scram is initiated, as required by RINSC Technical Specification 3.2.2. The new magnet power supplies are designed to measure and display the drop time for each shim safety blade.
If the answer to any of these questions is yes, then an NRC approved license amendment pursuant to IO CFR 50.90 shall be obtained before the modification is implemented.