United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 81-02: Failure of Gate Type Valves to Close Against Differential Pressure

                                                       SSINS No. 6820 
                                                       Accession No.: 
                                                       8011040283 
                                                       IEB 81-02 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555
                                     
                                April 9, 1981

IE Bulletin No. 81-02:   FAILURE OF GATE TYPE VALVES TO CLOSE AGAINST 
                         DIFFERENTIAL PRESSURE 

Description of Circumstances: 

As a part of its pressurized water reactor (PWR) Safety and Relief Valve 
Testing Program, the Electric Power Research Institute (EPRI) conducted 
limited testing of a number of valves used on PWRs as power-operated relief 
valve (PORV) isolation or block valves. These tests indicate a number of 
cases in which certain of these valves failed to fully close under 
conditions that approximated those of their intended service (i.e., 
saturated steam at approximately 2,400 psi). The valves that failed to fully 
close are gate type motor-operated valves that may be used in various 
safety-related applications in addition to PORV block valves. 

Background on EPRI Testing: 

The proposed full-scale qualification testing of PORV block valves, with a 
completion date of July 1, 1982, was first provided to the utilities in a 
September 5, 1980, draft of NUREG-0737. The item was formally issued, with 
Commission approval, in NUREG-0737 on October 31, 1980. 

The block valve qualification testing was proposed in NUREG-0737 primarily 
as an additional means of reducing the number of challenges to the emergency
core cooling system and the safety valves during plant operation. 

In anticipating a request for PWR block valve testing, EPRI decided to make 
provisions for the installation of block valves between the test steam 
source and the test PORV in July 1980 at the Marshall test facility. The 
Marshall test facility is a full-flow steam test facility owned by Duke 
Power Company. Test PORVs had been carefully selected, with close 
coordination between EPRI, its consultants and PWR utilities, to assure that 
PORVs representative of those in service or intended for service would be 
tested. However, for the block valves that have been tested concurrently, 
this selection process was not followed because an NRC block valve test 
program had not been formulated. Therefore, seven readily available valves 
were obtained and tested by EPRI, primarily to obtain some general baseline 
information on block valve closure capability. 

For the block valves that were tested, EPRI had not established, at least at
the time of testing, the population of plants, either operating or under 
construction, that might have a valve of the type needed for testing. In 
addition, it should be noted that the test conditions used at Marshall to 
date were only those that were determined to be applicable for steam testing
of PORVs. 
.

                                                           IEB 81-02 
                                                           April 9, 1981 
                                                           Page 2 of 4 

These test conditions were selected after review by EPRI, utilities, and PWR
NSSS vendors. NRC staff also reviewed and concurred with the test 
conditions. To date, there has been no similar specific determination by 
EPRI or the NRC staff as to the relevance of the Marshall block valve test 
conditions to the conditions in any specific PWR plant under which a block 
valve should be able to close to isolate a stuck-open PORV. 

To date, EPRI has tested a total of seven PORV block valves, all at the 
Marshall facility. During these tests, the following valves failed to fully 
close during the EPRI PORV block valve testing: 

1.   Westinghouse Electro-Mechanical Division (W-EMD) 3-inch Valves - These 
     valves, which are manufactured by W-EMD, can be identified by the 
     yokemounted nameplates that are stamped "WESTINGHOUSE" and include 
     "VALVE IDENT." and "VALVE I.D." numbers given in Table 1. Supplemental 
     analyses and water testing, performed by W-EMD, determined that a 
     4-inch valve also would not close fully and therefore is included in 
     this bulletin. The nameplate data on this valve are given in Table 1. 
     These analyses and tests also determined the threshold differential 
     pressure across the valves above which closure cannot be assured. These 
     values are given in Table 1. A list of power reactor facilities 
     believed to have the affected valves is given in Table 2. It is our 
     understanding that W-EMD has notified these facilities of the failure 
     of these valves to fully close. 

2.   Borg-Warner Nuclear Valve Division (BW-NVD) 3-inch 1500-pound Motor-
     Operated Gate Valves - These valves can be identified by BW-NVD part 
     numbers 75460, 77910, and 79190. Supplemental testing to determine 
     threshold differential pressures for less severe service has yet to be 
     completed. A list of power reactor facilities believed to have the 
     affected valves is given in Table 3. BW-NVD has submitted a 10 CFR Part
     21 report in which they indicated that they have notified these 
     facilities of the failure of these valves to fully close. (Note: 
     Similar valves with BW-NVD part numbers 74380 and 74380-1 have been 
     modified, retested, and demonstrated to close under test conditions. As 
     a result, they are not included in this bulletin.) 

3.   Anchor Darling 3-inch 1540-pound Double-Disc Valve - This valve, the 
     first of a series of specially designed valves, has been modified, 
     retested, and demonstrated to close under test conditions. The 
     remaining valves will be similarly modified during manufacture. As a 
     result, they are not included in this bulletin. 

It must be cautioned that Tables 2 and 3 may not be complete. For example, 
the staff is aware of one power reactor facility that obtained affected 
valves from another inventory. For this reason, this bulletin is applicable 
to all power reactor, facilities with an operating license or construction 
permit. 

The tests and analyses performed to date raise doubts as to the ability of 
the affected valves to close under less severe service conditions. These 
valves have also been supplied for utilization in a number of safety-related
.

                                                           IEB 81-02 
                                                           April 9, 1981 
                                                           Page 3 of 4 

applications. In the case of the W-EMD valves, they are also provided as 
spares or replacements through direct sales from the manufacturer. For this 
reason, this bulletin is applicable to the affected valves that are required
to close with a differential pressure across them in safety-related systems 
or as PORV block valves. 

The responsibility for notification and corrective actions based on adverse 
test results continues to lie with the utilities and vendors in the 
industry. NRC will continue to monitor the progress of the qualification 
program. All adverse test data will continue to be evaluated on a 
case-by-case basis.  NRC staff will take appropriate action, if necessary, 
to assure that the necessary corrective actions are made in a timely manner.

Actions to be Taken by Licensees: 

1.   Within 30 days of the issuance date of this bulletin, ascertain whether
     any of the affected valves have been installed, or are maintained as 
     spares for installation, where they are required to close with a 
     differential pressure across them in safety-related systems or as PORV 
     block valves. The differential pressures of concern include the 
     following: 

     a.   For the W-EMD manufactured valves, values in excess of the 
          threshold values in Table 1. 

     b.   For the BW-NVD valves, any value. 

2.   If no affected valves are identified, report this to be the case and 
     ignore the items below. 

3.   If any affected valves are identified as being installed, take 
     corrective action and evaluate the effect that failure to close under 
     any condition requiring closure would have on system(s) operability 
     pursuant to the facility technical specifications for continued 
     operation. 

4.   If any affected valves are identified as spares, either modify the 
     valves so that they are qualified for the intended service or obtain 
     qualified replacements prior to installation. 

5.   Within 45 days of the issuance date of this bulletin, submit a report 
     to NRC listing the affected valves identified, their service or planned
     service, the maximum differential pressure at which they would be 
     required to close, the safety consequences of the valve's failure to 
     close, the corrective action taken or planned, and the schedule for 
     completing the corrective action. 

Actions to be Taken by Construction Permit Holders: 

1.   Ascertain whether any of the affected valves are or will be installed 
     or maintained as spares for installation where they are required to 
     close 
.

                                                           IEB 81-02 
                                                           April 9, 1981 
                                                           Page 4 of 4 

     with a differential pressure across them in safety-related systems or 
     as PORV block valves. The differential pressures of concern include the
     following: 

     a.   For the W-EMD manufactured valves, values in excess of the 
          threshold values in Table 1. 

     b.   For the BW-NVD valves, any value. 

2.   If no affected valves are identified, report this to be the case and 
     ignore the items below. 

3.   If any affected valves are identified, either modify the valves so that
     they are qualified for the intended service or obtain qualified 
     replacements prior to startup. 

4.   Within 90 days of the issuance date of this bulletin, submit a report 
     to NRC listing the affected valves identified, their planned service, 
     the maximum differential pressure at which they would be required to 
     close, the safety consequences of the valve's failure to close, the 
     corrective action taken or planned, and the schedule for completing the
     corrective action. 

For those cases in which reports have already been submitted in accordance 
with the Technical Specification, 10 CFR Parts 21 and/or 50.55(e), this 
information need not be resubmitted. Rather, licensees or construction 
permit holders should reference this earlier report and submit only the 
additional information requested above. 

Reports, signed under oath or affirmation under the provisions of Section 
182a of the Atomic Energy Act of 1954, shall be submitted to the Director of
the appropriate NRC Regional Office and a copy shall be forwarded to the 
Director of the NRC Office of Inspection and Enforcement, Washington, D.C. 
20555. 

If you need additional information regarding this matter, please contact the
appropriate NRC Regional Office. 

This request for information was approved by GAO under blanket clearance 
number R0072 that expires November 30, 1983. Comments on burden and 
duplication should be directed to Office of Management and Budget, Room 
3201, New Executive Office Building, Washington, D.C. 20503. 

Attachments: 
1.   Table 1 - Identification of W-EMD 
       Manufactured Valves and Differential 
       Pressure Limits for Operation 
2.   Table 2 - Partial List of Plants With 
       Affected Valves Manufactured by W-EMD 
3.   Table 3 - Partial List of Plants With 
       Affected Valves Manufactured by BW-NVD 
4.   Recently issued IE Bulletins 
.

                                                           Attachment 1 
                                                           April 9, 1981 
                                                           IEB 81-02 
  
   TABLE 1. IDENTIFICATION OF W-EMD MANUFACTURED VALVES AND DIFFERENTIAL 
                    PRESSURE LIMITS FOR VALVE OPERATION 

Nominal        W-EMD 
Valve          Model          "VALVE                             ***
Size (in.)     Reference      IDENT."*       "VALVE I.D."**      (psid)

 3             3GM88          03OOOGM88   3GM58 or 3GM78 or 3GM88    1500
               3GM88          03002GM88   3GM58 or 3GM78 or 3GM88    1500
               3GM99          03001GM99   3GM58 or 3GM78 or 3GM88     750

 4             4GM88          04OOOGM88   4GM78 or 4GM88              750
               4GM88          04002GM88   4GM78 or 4GM88              750

 4             4GM87          04OOOGM87   4GM77                       750
               4GM87          04002GM87   4GM77                       750

  *  This number is found on the yoke-mounted nameplate and occupies the
     first nine positions of a 24-position number. It is used in evaluating 
     the functional P requirements. 

 **  This number is found on the yoke-mounted nameplate and occupies the 
     first three positions of a six-position number. Valves sold as spares 
     or replacements may not contain this number. 

***  Pressure below which valve will close (as shipped). 

Notes:    A "position" may contain more than one character. The 
          three-position "VALVE I.D." number consists of five digits in the 
          three positions; for example, 3 GM 78. 

          All nameplates have "VALVE IDENT." numbers, but those sold as 
          spares or replacements may not have "VALVE I.D." numbers. The 
          "VALVE IDENT. " number includes the manufacturer's model 
          reference, and the "VALVE I.D." number is a reference to the valve 
          system application. The "VALVE I.D." number also appears on 
          Westinghouse valve indexes and system flow diagrams. There is no 
          reference to the "VALVE IDENT. " number on these indexes or flow 
          diagrams. 
.

                                                           Attachment 2 
                                                           April 9, 1981 
                                                           IEB 81-02 

                   TABLE 2.  PARTIAL LIST OF PLANTS WITH 
                   AFFECTED VALVES MANUFACTURED BY W-EMD 

                            "VALVE IDENT." Number

                                                       04OOOGM88
                                                       04002GM88
                    03OOOGM88                          04OOOGM87
                    03002GM88           03001GM99      04002GM87

Plant 
Operating plants (supplied as spares or replacements except as noted):

Beaver Valley 1          X
Connecticut Yankee       X 
Farley 1, 2                                  X* 
Indian Point 2           X 
Kewaunee                 X 
North Anna 1, 2          X 
Oconee 1, 2, 3           X                                  X 
San Onofre 1             X 
Surry 1, 2               X                   X              X 
Zion 1, 2                                                   X 

Nonoperating plants (supplied as original scope of supply except as noted):

Beaver Valley 2          X                                  X 
Braidwood 1, 2           X                                  X 
Byron 1, 2               X                                  X 
Callaway 1, 2            X                                  X 
Comanche Peak 1, 2       X                                  X 
Harris 1, 2, 3, 4                            X              X 
Jamesport 1, 2                               X              X 
Marble Hill 1, 2         X                                  X 
San Onofre 2, 3                              X** 
Seabrook 1, 2                                X              X 
South Texas 1, 2                                            X 
Summer                   X                                  X 
Vogtle 1, 2                                  X              X 
Watts Bar 1, 2           X                                  X 
Wolf Creek               X                                  X 


  *  Transferred from inventory at another plant. 

 **  Spares or replacements. 
.

                                                           Attachment 3 
                                                            April 9, 1981 
                                                            IEB 81-02 

                   TABLE 3.  PARTIAL LIST OF PLANTS WITH 
                   AFFECTED VALVES MANUFACTURED BY BW-NVD 

Plant                                                       NVD-P/N

Arkansas Nuclear One, Unit 2                                75460
Bellefonte                                                  79190
Palo Verde                                                  77910
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