United States Nuclear Regulatory Commission - Protecting People and the Environment

Technical Specifications for Generic Letter 83-28, Item 4.3 (Generic Letter No. 85-09)



                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                           WASHINGTON, D. C. 20555

                                May 23, 1985

TO ALL WESTINGHOUSE PRESSURIZED WATER REACTOR LICENSEES AND APPLICANTS 
Gentlemen: 

SUBJECT:  TECHNICAL SPECIFICATIONS FOR GENERIC LETTER 83-28, ITEM 4.3 
          (Generic Letter 85-09) 

Reference:     "Safety Evaluation, Generic Westinghouse Modifications for 
               Reactor Trip System Automatic Actuation Using Shunt Coil Trip
               Attachments;" August 10, 1983, Letter from Darrell G. 
               Eisenhut, Director, Division of Licensing to J. J. Sheppard, 
               Chairman, Westinghouse Owners Group. 

Item 4.3 of Generic Letter 83-28, "Required Actions Based on Generic 
Implications of Salem ATWS Events," established the requirement for the 
automatic actuation of the shunt trip attachment for Westinghouse plants. 
Also, licensees are to submit any needed Technical Specification change 
requests as goon as practical following staff review and approval of the 
modified design. 

In the staff's evaluation of the Westinghouse generic design modifications 
(reference), the staff concluded that Technical Specification changes should
c be proposed by licensees to explicitly require independent testing of the 
undervoltage and shunt trip attachments during power operation and 
independent testing of the control room manual switch contacts during each 
refueling outage. The staff concluded that these tests are necessary to 
ensure reliable reactor trip breaker operation. In the staff's review of the
plant-specific responses to the generic letter, some licensees have 
indicated that changes to the Technical Specifications are not required for 
their plants. In such cases, the staff has found that the existing Technical
Specifications do not address the concerns mentioned above and the staff 
has. indicated that the required Technical Specification changes should be 
submitted. 

Therefore, licensees are requested to submit proposed Technical 
Specification changes which are responsive to the guidance noted in the 
enclosure. The enclosed guidance will be used to revise the Standard 
Technical Specifications for Westinghouse plants, and it will be used by the 
staff as a basis to review changes to Technical Specifications submitted by 
licensees and for the review of proposed Technical Specifications for 
operating license applications. 

For plants which have implemented the shunt trip modifications, a schedule 
for submittal of proposed Technical Specification changes should be 
established through discussions with the individual Project Manager for each
facility. In addition, discussions with the individual Project Managers 
should establish a schedule for plants which have not implemented the shunt 
trip modifications. Proposed Technical Specifications should be submitted as
soon as practical Am following staff review and approval of the modified 
design. For operating license applicants, proposed Technical Specifications 
should include requirements which are responsive to the enclosed guidance. 

8505210122 

                                    - 2 - 

This request for information was approved by the Office of Management and 
Budget under clearance number 3150-0011 which expires April 30, 1985. Should 
you have any questions, the staff contact is Rudy Karsch. Mr. Karsch can be 
reached on (301) 492-8563. 


                              Hugh L. Thompson, Jr., Director 
                              Division of Licensing 

Enclosure: 
Sample Technical Specifications 
List, of Generic Letters

                                  ENCLOSURE
                       TECHNICAL SPECIFICATION CHANGES
                          FOR REACTOR TRIP BREAKERS
                            (WESTINGHOUSE PLANTS)

BACKGROUND 

As a consequence of the Salem ATWS event, Item 4.3 of Generic Letter 83-28 
established the requirement for the automatic actuation of the shunt trip 
attachment for reactor trip breakers. Further, licensees are to submit any 
needed technical specification change requests prior to declaring the 
modified system operable. A number of the responses from operating reactors 
have indicated that no technical specification changes are required. 

The staff has reviewed the guidance provided in the Standard Technical 
Specifications (STS) for Westinghouse Plants, NUREG-0452, and finds that 
additional clarification of both the limiting conditions of operation and 
surveillance requirements are appropriate as a result of the staff's 
evaluation of design modifications to include automatic actuation of the 
shunt trip attachments. The STS for Westinghouse plants will be revised to 
include the changes noted herein. Pending formal revision of the STS, this 
document provides guidance to licensees and operating license applicants on 
appropriate technical specifications in response to Item 4.3 of the Generic 
Letter. 

                                    - 2 - 

DISCUSSION 

The operability requirements for the reactor trip breakers are specified in 
Table 3.3-1 of the STS. The specification states that both reactor trip 
breakers shall be operable in Modes 1 and 2. In addition, both breakers are 
to be operable when in Modes 3, 4, and 5 if the breakers are in the closed 
position and the control rod drive system is capable of rod withdrawal. The 
action statements for an inoperable breaker require that the plant be in at 
least hot standby within six hours for Modes 1 and 2, and that the breaker 
be restored to operable status in 48 hours or opened in the next hour when 
operating in Modes 3, 4, or 5. 

With the addition of the automatic actuation of the shunt trip attachment 
(STA), diverse features exist to effect a reactor trip for each breaker. If 
one of these diverse trip features is inoperable, a decision would have to 
be made with regard to the operability status of the reactor trip breaker. 
The definition of OPERABLE-OPERABILITY in Section 1.0 of the STS states that
a component shall be operable or have operability when it is capable of 
performing its safety function. Since either trip feature being operable 
would initiate a reactor trip on demand, it would be overly conservative to 
treat a breaker as inoperable if one of these diverse trip features were 
inoperable. However, on the other hand, the reliability of the reactor trip 
system would be reduced if each diverse trip feature is not maintained in an
operable status. 
.

                                    - 3 - 

The reactor trip breaker surveillance test should independently verify the 
operability of the shunt and undervoltage trip features of the reactor trip 
breakers as part of a single sequential test procedure. Therefore, the 
surveillance test which identifies a failure of one diverse trip feature 
also confirms the operability of the other trip feature. As a consequence, 
there is a high degree of confidence that the operable trip feature would be
capable of initiating a reactor trip in the next 48 hours. Accordingly, an 
additional action statement will be included in the STS for the reactor trip
breakers to permit continued plant operation for up to 48 hours with one of 
the diverse trip features inoperable before further action needs to be 
taken. The additional action statement is as follows: 

     ACTION - With one of the diverse trip features (undervoltage or shunt 
     trip attachment) inoperable, restore it to OPERABLE status within 48 
     hours or declare the breaker inoperable and apply ACTION 12. The 
     breaker shall not be bypassed while one of the diverse trip features is 
     inoperable except for the time required for performing maintenance to 
     restore the breaker to OPERABLE status. 

The Westinghouse generic design modification includes test features which 
permit the independent testing to verify the operability of the shunt and 
undervoltage trip attachments. Some licensees have proposed changes to the 
surveillance requirements specified in Table 4.3-1 to specifically note the 
.

                                    - 4 - 

requirement for independent testing of the diverse trip features. As noted 
above, operability as applied to the diverse trip features of breakers may 
have different degrees of safety significance. In order to be consistent 
with the intent of the test features provided, the following notation will 
be included in Table 4.3-1 for reactor trip breakers: 

     "The TRIP ACTUATING DEVICE OPERATIONAL TEST shall independently verify 
     the OPERABILITY of the undervoltage and shunt trip attachments of the 
     Reactor Trip Breakers." 

In the evaluation of Westinghouse generic design, the staff noted that the 
procedures for testing the breakers did not include verification of the 
operability of the control room manual reactor trip switch contacts and 
wiring in the manual initiation circuits. However, it was noted that a 
procedure for this test was being developed by Westinghouse Owners Group. In
its conclusions, the staff noted that licensees should propose technical 
specification changes to explicitly provide for periodic independent testing
of the control room manual switch contacts during each refueling outage. 

Table 4.3-1 of the STS specifies that the manual reactor trip function be 
tested at least once per 18 months. However, unlike the modification for 
automatic actuation of the shunt trip attachments, test features are not 
incorporated in the design for most plants to facilitate the independent 
testing of the shunt and undervoltage trip circuits for the manual reactor 
trip function. As noted in the staff's evaluation of the Westinghouse 
generic 
.

                                    - 5 - 

design, the surveillance tests for the manual reactor trip may be performed 
in a manner to verify the operability of the reactor trip switch contacts 
and wiring to the circuit breakers. This test may be performed by voltage 
measurements at terminal blocks of the reactor trip breakers and it is not 
necessary to physically trip the breakers during this test. 

Two precautions are applicable if this method of testing is implemented. One
is that the "Block auto shunt trip" switch would have to be used to preclude
sensing the application of power to the shunt trip coil via the automatic 
shunt trip feature. The second is that with the breaker in a tripped 
condition, voltage would be measured across the combination of the shunt 
trip coil and series breaker "a" auxiliary contact due to the presence of 
the breaker closed position status light located in parallel with the 
normally open manual reactor trip switch contacts. If voltage measurements 
are used for this test, the indicating light would have to be removed or 
other appropriate action taken such that measurements would not be 
ambiguous. 

Therefore, the following notation will be added to Table 4.3-1 of the STS to
be consistent with the intent of the staff's evaluation of the manual 
reactor trip function: 

     "The TRIP ACTUATING DEVICE OPERATIONAL TEST shall independently verify 
     the OPERABILITY of the shunt and undervoltage trip circuits for the 
     Manual Reactor Trip Function." 
.

                                    - 6 - 

The current STS do not address surveillance requirements for the reactor 
trip bypass breakers. In the evaluation of the Westinghouse generic design 
modifications, the staff noted that it would require that the operability of
the bypass breakers be verified prior to it being placed into service. In 
response to this requirement, some licensees have noted that the bypass 
breakers are maintained in a racked out position during normal operation and
the required testing is performed by moving the breaker to the test 
position. In the test position, the operability of the shunt trip attachment 
is verified via the local shunt trip switch at the breaker. Following this 
test, the breaker is racked into the operate position and closed to pe mit 
testing of its associated reactor trip breaker. Since the operation of the 
undervoltage trip attachment for the bypass breakers are actuated by the 
opposite train of the protection systems, it has been proposed to test this 
feature during refueling outages. Finally it was noted that the testing of 
the manual reactor trip function which is performed during refueling outages
includes operation of the bypass breakers to verify the operability of the 
manual trip circuit(s). 

The staff conclusion is that the above proposed methods for testing bypass 
breakers is acceptable. The basis for this conclusion includes recognition 
of the fact that a readily available means does not exist to permit testing 
of the automatic trip feature of bypass breakers and that confirmation of 
the operability of the shunt trip attachment when the breaker is placed in 
service provides additional assurance that the bypass breaker could be 
tripped via a manual reactor trip. Therefore, if a bypass breaker is not 
tripped via its undervoltage trip attachment due to a valid automatic trip 
signal during breaker testing, or a manual reactor trip is intentionally 
initiated, greater assurance will be provided for the capability.to trip a 
bypass breaker. 
.

                                    - 7 - 

As a consequence of the staff review of Westinghouse plants with relay logic
it was recognized that for some plants the manual reactor trip function does
not actuate the shunt trip attachment of bypass breakers, but rather the 
undervoltage trip attachment. Further, the capability is provided from the 
protection system racks to individually trip each bypass breaker manually. 
Therefore, for plants with this design the bases for testing the operability
of bypass breakers, when they are placed in service for testing of reactor 
trip breakers, would be met by a trip of the undervoltage trip attachment of
the bypass breakers initiated manually from the protection system racks. 
Also with regards to the test of the manual reactor trip function for plants 
with this design, this test should confirm the operability of the 
undervoltage trip. 

Accordingly, Table 4.3-1 of the STS will be revised to include surveillance 
test requirements for reactor trip bypass breakers as follows: 

1.   Shunt trip attachment operability tests prior to placing the breaker in
     service. 

2.   Undervoltage trip attachment operability tests at least once per 18 
     months. 

3.   Manual reactor trip operability tests at least once per 18 months.

If the shunt trip attachment is actuated on a manual reactor trip, the 
     test shall independently verify the operability of the undervoltage and
     shunt trip circuits. 
.
                                   - 8 - 

For plants that do not actuate the shunt trip attachment of the bypass 
breakers on a manual reactor trip, item 1 would be replaced by a remote 
manual undervoltage trip attachment operability test when the bypass breaker
is placed in service for reactor trip breaker testing. 

Enclosed are marked-up pages of the applicable STS tables with these 
changes. Until such time that these changes are incorporated in the STS, 
proposed changes to plant specific technical specifications will be 
evaluated by the staff based on this guidance. 

For plants which do not have bypass breakers, technical specification 
changes are not required at this time. The need for any change to technical 
specifications will be identified on a plant specific basis following the 
staff review of licensee responses to Item 4.5 of Generic Letter 83-28. 
Page Last Reviewed/Updated Thursday, June 27, 2013