Bulletin 80-16: Potential Misapplication of Rosemount Inc. Models 1151 And 1152 Pressure Transmitters with Either "A" or "D" Output Codes
SSINS No.: 6820
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
June 27, 1980
IE Bulletin No. 80-16
POTENTIAL MISAPPLICATION OF ROSEMOUNT INC. MODELS 1151 AND 1152 PRESSURE
TRANSMITTERS WITH EITHER "A" OR "D" OUTPUT CODES
Description of Circumstances
The NRC has recently been advised through 10 CFR 21 reports that a potential
misapplication problem exists on Rosemount Inc. Models 1151 and 1152
pressure transmitters with either "A" or "D" output codes. The pressure
transmitters are used in both pressure and differential pressure
applications. Applications include pressurizer pressure monitoring (pressure
transmitters) and reactor vessel level monitoring (differential pressure
The potential misapplication problem occurs when the above specified
transmitters are exposed to excessive over or reverse pressures. These
pressures can result in ambiguous signal outputs from the transmitter to
control and/or indication components. These ambiguous signals could result
in erroneous control action, such as an open signal to a solenoid valve
rather than a closed signal, or an erroneous indication signal, such as an
indication in the normal operating range when a pressure outside the normal
range actually exists.
Enclosure 1 contains Rosemount Inc.'s technical description of the potential
application problems for Pressure Transmitters Model 1152. This information
is applicable to Model 1151 Pressure Transmitters also. This information
includes the reasons for the maloperation of the transmitters, a typical
pressure versus current output curve and examples of the results of the
maloperations. Available information indicates that the problem was reported
to each customer who was furnished the subject transmitters by Rosemount
Actions to be Taken by Licensees of Power Reactor Operating Facilities and
Holders of Construction Permits:
1. Determine if your facility has installed or plans to install Rosemount
Inc. Model 1151 or 1152 pressure transmitters with output codes "A" or
"D" in any safety-related application.
2. If it is determined that your facility has the transmitters described
in 1 above in any safety-related application, determine whether they
can be exposed to input pressures that could result in anomalous output
signals during normal operation, anticipated transients or design bases
accidents. If the affected transmitters can be exposed to input
pressures that could result in anomalous output signals, perform a
worst case analysis to determine whether the anomalous signals could
result in violating any
IE Bulletin No. 80-16 June 27, 1980
Page 2 of 2
design basis assumption. The safety-related application shall include
control, protective or indication functions. If any safety-related
application does not conform to the above requirements address the
basis for continued plant operation until the problem is resolved and
provide an analysis of all potential adverse system effects which could
occur as a result of a postulated pressure transmitter maloperation
described in Enclosure 1 of this bulletin. In each instance, the
analysis should include the effects of postulated transmitter
maloperation as it relates to indication, control and protective
functions. The analysis shall address both incorrect automatic system
operation and incorrect operator actions caused by erroneous
indications. Address the conformance to IEEE 279, section 4.20 in your
analysis. Include in your analysis the following table:
a. Complete model number.
b. Transmitter range limits.
c. Transmitter range setting.
d. Range of process variable measured for (1) normal and (2) accident
e. Values of process variable which could produce anomalous
indication based upon your evaluation.
3. Submit a complete description of all corrective actions required as a
result of your analysis and evaluations, together with the schedule for
accomplishing the corrective actions.
4. Provide the response in writing within 30 days for facilities holding
an operating license or are NTOL applicants* and within 60 days for
those facilities holding construction permits. Reports shall be
submitted to the Director of the appropriate NRC Regional Office with
copies forwarded to the U.S. Nuclear Regulatory Commission, Office of
Inspection and Enforcement, Division of Reactor Operations Inspection
(for facilities holding an operating license) or Division of Reactor
Construction Inspection (for facilities holding a construction permit),
Washington, D.C. 20555.
* The plants that are the subject of the near term operating license reviews
are: North Anna 2, Salem 2, Sequoyah 1 & 2, McGuire 1 & 2, Diablo 1 & 2, and
Approved by GAO, B180225 (R0072); clearance expires July 31, 1980. Approval
was given under a blanket clearance specifically for identified generic
Enclosure: Extract from Rosemount Inc.
letter to NRC dated June 6, 1980
Enclosure to Bulletin 80-16
EXTRACT FROM ROSEMOUNT, INC.
LETTER TO NRC DATED JUNE 6, 1980
(i) Name and address of the individual or individuals informing the
(ii) Identification of the facility, the activity, or the basic component
supplied for such facility or such activity within the United States
which is affected by the potential application problem.
Rosemount Model 1152 Pressure Transmitters with output codes "A"
(iii) Identification of the firm making the report.
Rosemount Inc. 12001 W. 78th St.
Eden Prairie, MN. 55344
(iv) Nature of the potential applications problem.
Rosemount's Model 1152 pressure transmitter provides a specified linear
output of 4 to 20 mA throughout the calibrated range of operation. The
transmitter output is not specified by Rosemount for pressures outside
of the calibrated range of operation. It has been observed in a limited
number of transmitters that an output between 4 and 20 mA can occur
with certain input pressures outside of the calibrated range. These
ambiguous outputs can occur in both an over pressure condition and a
reverse pressure condition. Both conditions arise when the center
diaphragm of the pressure sensor bottoms out against either of the
fixed capacitor plates. In each case the normal capacitance signal
becomes a very high capacitance signal which affects the operation of
the electronic circuit.
For the over pressure condition, the effect of the high capacitance
from the sensor is a modulated output on the oscillator circuit which
may cause the output current of the transmitter to drop below 20 mA. In
a limited sample size, the ambiguous output during this over pressure
condition occurred in 5% of the transmitters at ambient conditions.
Referring to the attached graph, this does not occur until the over
pressure condition is > 140% of the upper range limit regardless of
span. At that point a discontinuity can occur with the output current
instantaneously decreasing to less than 20 mA. As an example of this
potential applications problem, the upper range limit of a range 5 1152
differential pressure transmitter (Model 1152DP5A22) is 750"H20. The
range of this pressure transmitter can be set from 0 to 150"H20. If the
ambiguous output in the over pressure condition is to occur,it will
occur at 140% or more of the upper range limit or, in this case, at
pressures > 1050"H 0 (750"H20 x 1.4). The transmitter then could give
an output less than 20 mA at a pressure that is, in this example, seven
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times 1050"H20 / 150"H20) the upper range value. Note that the significant
figure for use in determining the pressure above which an ambiguous output
can occur is the specified upper range (750" H20 in this example) not the
customer selected upper range value (150"H20 in this example).
For the reverse pressure condition, the effect of the high capacitance from
the sensor is the oscillator circuit drawing more current which may cause
the output current of the transmitter to exceed 4 mA. In a limited sample
size, the ambiguous output during this reverse pressure condition occurred
in 55% of the transmitters at ambient conditions. Referring to the attached
graph, this does not occur until the reverse pressure condition exceeds 140%
of the upper range limit regardless of the span. At this point the output
may exceed 4 mA. As an example of this potential applications problem
consider the range 5 differential transmitter in the previous paragraph. If
the ambiguous output in the reverse pressure condition is to occur, it will
occur at 140% or more of the upper range limit, or in this case at reversed
pressures > 1050" H20 (750"H 0 x 1.4). The transmitter then could give an
output greater than 4 mA at a pressure that is, in this example, seven times
(1050" H20 / 150" H20) the upper range value, but reversed. Also note that
with absolute pressure units a reverse pressure is not possible since the
low pressure side of the cell is evacuated. With gage units a reverse
pressure is possible only if a vacuum is present on the connected part since
the low pressure side of the cell is vented to ambient atmosphere. Since the
maximum reverse pressure would be one atmosphere, only range 3 and 4 gage
units could obtain a reverse pressure exceeding 140% of the upper range
Due to the effects of radiation or elevated temperature, we believe that the
frequency of occurrence of the ambiguous output will be greater in a
radiated or an elevated temperature environment than was experienced in our
limited sample size testing, which was in a non-radiated ambient temperature
After the occurrence of an ambiguous output from an over pressure or a
reverse pressure condition, the transmitter will return to specified
operation when the input pressure returns to the calibrated range, provided
the over pressure or reverse pressure was within the maximum pressure limits
specified by Rosemount.
(v) The date on which the information of the potential applications problem
Amended to March 6, 1980.
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(vi) The number and location of all in use at, supplied for, or being
supplied for one or more facilities or activities subject to the
regulations in this part.
(vii) The corrective action recommended to negate this potential application
The safety system should be analyzed in view of this supplementary
report to determine if a potential application problem exists and
appropriate corrections to the safety system should be
(viii) Any related to the defect or failure to comply about the facility,
activity, or basic component that has been, is being, or will be given or
purchasers or licensees.
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