Bulletin 80-16: Potential Misapplication of Rosemount Inc. Models 1151 And 1152 Pressure Transmitters with Either "A" or "D" Output Codes

                                                            SSINS No.: 6820 
                                                            Accession No.: 

                                UNITED STATES
                           WASHINGTON, D.C. 20555

                                June 27, 1980

                                                      IE Bulletin No. 80-16 


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. 
     f.   Service/function. 

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 

          Not Applicable. 

(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" 
          or "D". 

(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

                                    - 2 -

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
     was obtained. 

          Amended to March 6, 1980. 

                                    - 3 -

(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. 

          Not applicable. 

(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. 

          Not applicable. 

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