Erratic Behavior of Static O Ring Differential Pressure SwitchesML031220689 |
Person / Time |
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Site: |
Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill |
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Issue date: |
06/10/1986 |
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From: |
Jordan E NRC/IE |
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To: |
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References |
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IN-86-047, NUDOCS 8606090487 |
Download: ML031220689 (6) |
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Similar Documents at Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill |
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Category:NRC Information Notice
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Mclaughlin on NRC, Regarding NRC Information Notice 2006-13: Groundwater Contamination 2020-09-03 The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000000]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] OR [[:Skagit]] OR [[:Marble Hill]] </code>.
[Table view]The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000000]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] OR [[:Skagit]] OR [[:Marble Hill]] </code>. |
SSINS No.: 6835 IN 86-47 UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, DC 20555 June 10, 1986 IE INFORMATION NOTICE NO. 86-47: ERRATIC BEHAVIOR OF STATIC "O" RING
DIFFERENTIAL PRESSURE SWITCHES
Addressees
All boiling water reactor (BWR) and pressurized water reactor (PWR) facilities
holding an operating license (OL) or a construction permit (CP).
Purpose
This information notice is intended to advise licensees of erratic behavior of
certain differential pressure switches supplied by SOR, Incorporated (formerly
Static "O" Ring Pressure Switch Company) which apparently caused failure of the
LaSalle 2 reactor to scram automatically when it was operating with water level
below the low level setpoint. Similar switches are also installed in the high
pressure core spray system and the residual heat removal system.
It is expected that recipients will review this information for applicability
to their reactor facilities and consider actions, if appropriate, to preclude
the occurrence of a similar problem at their facility. Suggestiohs contained
in this notice do not constitute NRC requirements. Therefore, no specific
action or written response is required.
The NRC evaluation of this incident is continuing. If specific action is
determined to be necessary, a separate notification will be issued.
Summary of Circumstances
On June 1, 1986, LaSalle 2 experienced a feedwater transient that resulted
in a low reactor water level. One of the four low level trip channels actuated, resulting in a half scram. The operator recovered level and operation was
continued. Subsequent reviews by licensee personnel raised concerns that the
level had apparently gone below the scram setpoint and thus a malfunction of
the reactor scram system may have occurred. Based on this concern, the licensee
declared an "Alert" and shut the plant down. The NRC dispatched an augmented
inspection team to the site. Subsequently, the licensee found that the "blind"
switches which operate on differential pressure perform erratically. The
licensee also found erratic operation for similar switches in the high pressure
core spray system and the residual heat removal system which operate valves in
the minimum flow recirculation lines. Based on these results, the licensee
declared all emergency core cooling systems in LaSalle 1 and 2 to be inoperable.
Both units are in cold shutdown pending further evaluation of the problem.
8606090487
IN 86-47 June 10, 1986
Description of Circumstances
The following description was constructed from a preliminary sequence of events
prepared by the augmented inspection team and from other input by the team.
At 4:20 A.M. on Sunday, June 1, 1986, LaSalle 2 was operating at 93 percent of
full power. Both turbine-driven feedwater pumps were operating, with the "A"
pump in manual control and the "B" pump in automatic control. The motor-driven
feedwater pump was in standby. While a surveillance test was being conducted
on feedwater pump "A", the turbine governor valve opened further and caused pump
speed and reactor water level to start increasing. At about the same time, the
automatic control systems for both turbine-driven pumps locked out. The reactor
operator regained control of feedwater pump "A" and ranback feedwater pump speed
in an attempt to restore water level to the nominal value (36 inches on the
narrow range recorder). A few seconds later when the control system was reset, the "B" feedwater pump controller automatically ranback the pump speed to zero
for no apparent reason. Reactor water level started falling at about
2 inches/second.
Subsequently, the reactor protection system responded via separate level switches
to the falling reactor water level by reducing recirculation flow to reduce power, and the operator started the motor-driven feedwater pump to increase level. The
level continued to fall for a few more seconds before turning around. The
minimum reactor scram setpoint required in the technical specification is
11 inches. The level channels are normally set to trip at 13.5 inches, and the
operators are trained to expect reactor scram by the time that the water level
reaches 12.5 inches. As the level was falling, one of the four reactor scram
level switches (the "0" switch) tripped at approximately 10 inches, causing a
"half scram." As designed, this did not initiate control rod motion. None of
the other three level switches tripped during this transient. No reactor scram
occurred during this transient, either automatically or manually.
In the BWR scram system logic, which is one-out-of-two-taken-twice, at least
one instrument channel in each scram system must trip to generate a scram
demand signal and thereby initiate control rod motion. Preliminary results
of the investigation indicate that the reactor water level fell to a minimum
value of about 4.5 inches on the narrow range instrumentation, which is several
inches below the specified scram setpoint but still 13 to 14 feet above the
top of reactor fuel. The period that the water level was below the specified
scram setpoint value was approximately 2 seconds. After feedwater flow turned
the transient around, the plant stabilized at a power level of about 45 percent.
The "B" scram system half scram was manually reset about 30 seconds later. The
power level was increased to 60 percent about 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> later.
Shortly after the subsequent shift change, the oncoming shift engineer's review
was effective in indicating that the reactor water level appeared to have fallen
below the scram setpoint and the level switches may not have performed properly.
He then requested that an instrumentation technician check the calibration of
the switches. The results were that the "A" and "C" switches, which are in the
"A" scram system, tripped at 10 and 13.5 inches respectively during the
calibration check; the "B" and "D" switches, which are in the "B" scram system, tripped at 11 and 13.5 inches respectively. The switches were readjusted to
IN 86-47 June 10, 1986 trip at 13.5 inches. Based on these results, the operating staff believed that
a malfunction of the scram system may have occurred. An orderly shutdown of the
plant was initiated at 2:00 P.M. (COT). At 2:30 P.M., the resident inspector
was notified, and at 5:30 P.M., the NRC Operations Center was called via the
emergency notification system and informed of this event by the licensee.
At 6:20 P.M., the licensee decided that the "A" scram system had failed to
perform during the transient. The "A" scram system was manually tripped
providing a half scram on the side that had apparently malfunctioned. The
orderly shutdown was continued, and an "Alert" was declared. When all the
control rods had been fully inserted at 9:22 the next morning, the Alert was
terminated.
On Monday, June 2, the NRC determined that the incident warranted a thorough
investigation. The NRC Regional Administrator dispatched an augmented inspection
team to the plant site.
On Monday evening, June 2, the licensee checked the calibration of the reactor
scram water level switches by varying the actual level in the vessel. The
results were that the "A" and "C" switches tripped at indicated levels of 9.0
and 6.9 inches respectively and the "B" and "D" switches tripped at 3.9 and 10.2 inches respectively. These data were obtained about 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> after the switches
had been calibrated according to plant procedures and suggest a non-trivial
difference. Additional data obtained over the next two days by varying reactor
water level demonstrated continued erratic behavior of switch setpoints.
On Saturday, June 7, after calibrating the Static "O" Ring flow switch which
actuates the minimum flow recirculation valve in the high pressure core spray
system, the licensee performed a different test using actual system flow. The
switch actuated when flow was at 530 gpm instead of 1000 gpm where it had been
set to actuate. The licensee found similar performance of flow switches in the
residual heat removal system. The licensee now suspects all Static "O" Ring
differential pressure switches and has declared all emergency core cooling
systems in both units to be inoperable. Both units remain in cold shutdown.
Discussion:
It appears at present that the water level decreased below the scram setpoint
for about two seconds and reached a minimum level of about 4.5 inches. This is
based on a recording from the narrow range water level instrument and records
from the startup testing data acquisition system which recorded levels from the
same transmitter. Had the reactor operator been aware of this fact before the
water level had increased to a level above the setpoint, tie reactor operator
would have been expected to scram the reactor manually.
The differential pressure switches which provide the water level trip input to
the reactor scram system were provided by SOR, Incorporated. These level switches
are not original equipment; but were installed during replacement of equipment
in secondary containment. Affected licensees had determined that the original
switches were not qualified to operate in the environment created by an accident.
Operation of the SOR switches has been demonstrated to be erratic with little
correlation between the setpoints established during atmospheric pressure
IN 86-47 June 10, 1986 calibrations and switch actuations under system pressure conditions. Exercising
the switches by applying successive differential pressure cycles appears to mask
erratic setpoint behavior. Similar problems with SOR differential pressure
switches have been reported at Oyster Creek.
Per plant procedure, the switches for reactor water level had been exercised
prior to calibration following failure of the reactor to scram automatically.
For this reason, performance of the level switches may have been different during
calibration than during the event. Further, none of the level switches in the
LaSalle 2 reactor scram system operate in conjunction with individual level
transmitters. Therefore, the calibration and performance of the individual low
level trip channels cannot easily be compared to each other. In effect, the
operator is blind to switch performance.
The vendor has indicated that those plants identified in Attachment 1 have
similar differential pressure switches. This list of plants includes pressurized
water reactors as well as boiling water reactors. NRC intends to meet with
representatives of General Electric Company, SOR Incorporated, and interested
licensees at 10 A.M. on Thursday, June 12, 1986, in Bethesda, Maryland to
discuss experience with the switches.
It is suggested that licensees consider advising their reactor operators of the
LaSalle incident and providing guidance to them as to how to promptly detect
the occurrence of a similar problem at their plants and the proper remedial
action to be taken.
No specific action or written response is required by this notice. If you have
any questions regarding this matter, please contact the Regional Administrator
of the appropriate regional office or this office.
or an
Divisi of Emergency Preparedness
and Egineering Response
Office of Inspection and Enforcement
Technical Contacts: J. T. Beard, NRR
(301) 492-4415 Roger W. Woodruff, IE
(301) 492-7207 Attachments:
1. Plants with Similar Differential Pressure Switches
2. List of Recently Issued IE Information Notices
Attachment 1 IN 86-47 June 10, 1986 PLANTS WITH SIMILAR DIFFERENTIAL PRESSURE SWITCHES
PLANT SOR MODEL NUMBER
Penn. Pwr. & Light/Susquehanna 103/B202 So. Cal. Edison/San Onofre 103/B903 TVA/Brown's Ferry 103/8212 TVA/Sequoyah 103/BB212
103/BB203
103/BB803 WPPS 103/BB203 GPU/Oyster Creek 103/B905
103/BB212
103/B212
103/B202 N.E. Nuc./Millstone 103/B903 South Texas Projects 103/BB212
103/BB803 Commonwealth Edison/LaSalle 103/B202
103/8212
103/B203
103/BB203
103/BB212
103/BB205
103/68202
Attachment 2 IN 86-47 June 10, 1986 LIST OF RECENTLY ISSUED
IE INFORMATION NOTICES
Information Date of
Notice No. Subject Issue Issued to
86-46 Improper Cleaning And Decon- 6/12/86 All power reactor
tamination Of Respiratory facilities holding
Protection Equipment an OL or CP and
fuel fabrication
facilities
86-45 Potential Falsification Of 6/10/86 All power reactor
Test Reports On Flanges facilities holding
Manufactured By Golden Gate an OL or CP and
Forge And Flange, Inc. research and test
facilities
86-44 Failure To Follow Procedures 6/10/86 All power reactor
When Working In High Radiation facilities holding
Areas an OL or CP and
research and test
reactors
86-43 Problems With Silver Zeolite 6/10/86 All power reactor
Sampling Of Airborne Radio- facilities holding
iodine an OL or CP
86-42 Improper Maintenance Of 6/9/86 All power rector
Radiation Monitoring Systems facilities holding
an OL or CP
86-41 Evaluation Of Questionable 6/9/86 All byproduct
Exposure Readings Of Licensee material licensees
Personnel Dosimeters
86-32 Request For Collection Of 6/6/86 All power reactor
Sup. 1 Licensee Radioactivity facilities holding
Measurements Attributed To an OL or CP
The Chernobyl Nuclear Plant
Accident
86-40 Degraded Ability To Isolate 6/5/86 All power reactor
The Reactor Coolant System facilities holding
From Low-Pressure Coolant an OL or CP
Systems in BWRS
OL = Operating License
CP = Construction Permit
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list | - Information Notice 1986-01, Failure of Main Feedwater Check Valves Causes Loss of Feedwater System Integrity and Water-Hammer Damage (6 January 1986)
- Information Notice 1986-02, Failure of Valve Operator Motor During Environmental Qualification Testing (6 January 1986)
- Information Notice 1986-03, Potential Deficiencies in Enviromental Qualification of Limitorque Motor Valve Operator Wiring (14 January 1986)
- Information Notice 1986-04, Transient Due to Loss of Power to Intergrated Control System at a Pressurized Water Reactor Designed by Babcock & Wilcox (31 January 1986)
- Information Notice 1986-05, Main Steam Safety Valve Test Failures and Ring Setting Adjustments (31 January 1986)
- Information Notice 1986-06, Failure of Lifting Rig Attachment, While Lifting Upper Guide Structure at St. Lucie Unit 1 (3 February 1986, Topic: Control of Heavy Loads)
- Information Notice 1986-06, Failure of Lifting Rig Attachment, while Lifting Upper Guide Structure at St. Lucie Unit 1 (3 February 1986)
- Information Notice 1986-07, Lack of Detailed Instruction & Inadequate Observance of Precautions During Maintenance & Testing of Diesel Generator Woodward Governors (3 February 1986)
- Information Notice 1986-08, Licensee Event Report (LER) Format Modification (3 February 1986)
- Information Notice 1986-09, Failure of Check & Stop Check Valves Subjected to Low Flow Conditions (3 February 1986)
- Information Notice 1986-10, Degradation of Reactor Coolant System Pressure Boundary Resulting From Boric Acid Corrosion. (5 January 1995, Topic: Boric Acid)
- Information Notice 1986-10, Feedwater Line Break (10 November 1988, Topic: Coatings, Anchor Darling)
- Information Notice 1986-10, Degradation of Reactor Coolant System Pressure Boundary Resulting from Boric Acid Corrosion. (5 January 1995, Topic: Boric Acid)
- Information Notice 1986-11, Anomalous Behavior of Recirculation Loop Flow in Jet Pump BWR Plants (31 December 1986)
- Information Notice 1986-13, Standby Liquid Control System Squib Valves Failure to Fire (21 February 1986, Topic: Squib)
- Information Notice 1986-13, Standby Liquid Control Squib Valves Failure to Fire (5 August 1986, Topic: Squib)
- Information Notice 1986-14, Overspeed Trips of AFW, HPCI & RCIC Turbines (26 August 1991, Topic: Fire Barrier)
- Information Notice 1986-14, Overspeed Trips of Afw, HPCI & RCIC Turbines (26 August 1991)
- Information Notice 1986-15, Loss of Offsite Power Caused by Problems in Fiber Optics Systems (10 March 1986, Topic: Squib)
- Information Notice 1986-16, Failures to Identify Containment Leakage Due to Inadequate Local Testing of BWR Vacuum Relief System Valves (11 March 1986, Topic: Squib)
- Information Notice 1986-17, Update of Failure of Automatic Sprinkler System Valves to Operate (24 March 1986, Topic: Squib)
- Information Notice 1986-18, NRC On-Scene Response During a Major Emergency (26 March 1986, Topic: Squib, Backfit)
- Information Notice 1986-19, Reactor Coolant Pump Shaft Failure at Crystal River (21 March 1986, Topic: Squib)
- Information Notice 1986-20, Low-Level Radioactive Waste Scaling Factors, 10 CFR Part 61 (28 March 1986, Topic: Squib)
- Information Notice 1986-21, Recognition of American Society of Mechanical Engineers Accreditation Program for N Stamp Holders (31 March 1986, Topic: Squib)
- Information Notice 1986-22, Underresponse of Radiation Survey Instrument to High Radiation Fields (31 March 1986, Topic: High Radiation Area, Squib)
- Information Notice 1986-23, Excessive Skin Exposures Due to Contamination with Hot Particles (9 April 1986)
- Information Notice 1986-23, Excessive Skin Exposures due to Contamination with Hot Particles (9 April 1986)
- Information Notice 1986-24, Respirator Users Notice: Increased Inspection Frequency for Certain Self-Contained Breathing Apparatus Air Cylinders (11 April 1986, Topic: Hydrostatic)
- Information Notice 1986-25, Traceability and Material Control of Material and Equipment, Particularly Fasteners (11 April 1986)
- Information Notice 1986-26, Potential Problems in Generators Manufactured by Electrical Products Incorporated (17 April 1986)
- Information Notice 1986-27, Access Control at Nuclear Facilities (21 April 1986, Topic: Contraband)
- Information Notice 1986-28, Telephone Numbers to the NRC Operations Center and Regional Offices (24 April 1986)
- Information Notice 1986-29, Effects of Changing Valve Moter-Operator Switch Settings (25 April 1986)
- Information Notice 1986-30, Design Limitations of Gaseous Effluent Monitoring Systems (29 April 1986)
- Information Notice 1986-31, Unauthorized Transfer and Loss of Control of Industrial Nuclear Gauges (14 July 1986)
- Information Notice 1986-32, Request for Collection of Licensee Radioactivity Measurements Attributed to Chernobyl Nuclear Plant Accident (2 May 1986, Topic: Chernobyl)
- Information Notice 1986-33, Information for Licensee Regarding the Chernobyl Nuclear Plant Accident (6 May 1986, Topic: Chernobyl)
- Information Notice 1986-34, Improper Assembly, Material Selection, & Test of Valves & Their Actuators (13 May 1986)
- Information Notice 1986-34, Improper Assembly, Material Selection, & Test of Valves & their Actuators (13 May 1986)
- Information Notice 1986-35, Fire in Compressible Material at Dresden Unit 3 (15 May 1986, Topic: Chernobyl)
- Information Notice 1986-36, Change in NRC Practice Regarding Issuance of Confirming Letters to Principal Contractors (16 May 1986, Topic: Chernobyl)
- Information Notice 1986-37, Degradation of Station Batteries (16 May 1986, Topic: Chernobyl)
- Information Notice 1986-38, Deficient Operator Actions Following Dual Function Valve Failures (20 May 1986, Topic: Chernobyl)
- Information Notice 1986-39, Failures of RHR Pump Motors and Pump Internals (20 May 1986, Topic: Chernobyl)
- Information Notice 1986-40, Degraded Ability to Isolate the Reactor Coolant System from Low-Pressure Coolant Systems in Bwrs (5 June 1986, Topic: Chernobyl)
- Information Notice 1986-40, Degraded Ability to Isolate the Reactor Coolant System from Low-Pressure Coolant Systems in BWRs (5 June 1986, Topic: Chernobyl)
- Information Notice 1986-41, Evaluation of Questionable Exposure Readings of Licensee Personnel Dosimeters (9 June 1986, Topic: Chernobyl)
- Information Notice 1986-42, Improper Maintenance of Radiation Monitoring Systems (9 June 1986, Topic: Temporary Modification, Chernobyl)
- Information Notice 1986-43, Problems with Silver Zeolite Sampling of Airborne Radioiodine (10 June 1986, Topic: Chernobyl)
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