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See also: [[see also::IR 05000272/1986023]]


=Text=
=Text=
{{#Wiki_filter:' . * Corbin A. McNeill, Jr. Public Service Electric and Gas Company Public Service Electric and Ga? Company P 0. Box236. Hancocks Bridge. i\JJ 08038 609 339-4;300  
{{#Wiki_filter:' .
V:ce Pres*cen:  
Public Service Electric and Gas Company Corbin A. McNeill, Jr. Public Service Electric and Ga? Company P 0. Box236. Hancocks Bridge. i\JJ 08038 609 339-4;300 V:ce Pres*cen:
* February 13, 1987 NLR-N87017  
* February 13, 1987 NLR-N87017 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Attention:   Mr. Robert F. Heishman, Chief Vendor Programs Branch Division of Quality Assurance Vendor and Technical Training Center Programs Off ice of Inspection and Enforcement Gentlemen:
United States Nuclear Regulatory  
NRC INSPECTION 50-272/86-23 AND 50-311/86-23 REVISED RESPONSE TO INSPECTION REPORT SALEM GENE~TING STATION DOCKET NOS. 50-272 AND 50-311
Commission  
        ~  meeting was held on Fe~ruary 3, 1987 at NRC Region I to discuss our responses to those Salem EQ inspection findings subject to the 10CFR50.49 enforcement criteria delineated in Generic Letter 86-15. During the meeting, NRC staff representatives were notified of changes to our previous responses (dated November 7, 1986 and December 15, 1986) to the subject inspection report.
Document Control Desk Washington, DC 20555 Attention:  
Those changes are being formally submitted by this letter and its attachment.
Mr. Robert F. Heishman, Chief Vendor Programs Branch Division of Quality Assurance  
We first request that our previous response to Potential Enforcement/Unresolved Item 50-272/86-23-03: 50-311/86-23-03 regarding the qualification of Rockbestos EPR and Coaxial cahle be withdrawn. An in-depth review of our November 7_, 1986 response to this finding was performed by PSE&G prior to the meeting at NRC Region I. The results of the review determined that although PSE&G EQ personnel were knowledgeable of the additional tests which substantiated the results of the questionable Rockbestos test reports noted in IE Information Notice 84-44, these test reports had not been formally analyzed and referenced in the Rockbestos EQ file. As such, the inspection finding in this area is not disputed.
Gentlemen:
The review of the response to Potential Enforcement/Unresolved Item 50-272/86-23-04: 50-311/86-21-04 also uncovered certain discrepancies in the information presented with regard to the Limitorque gear case grease reliefs. Correction of these
Vendor and Technical  
 
Training Center Programs Off ice of Inspection  
Q *
and Enforcement  
. '   Document Control Desk           2                 2/13/87
NRC INSPECTION  
* discrepancies does not alter our position that tha grease reliefs were not required for the operability of the Limitorque operators in containment under Salem plant-specific post-accident conditions.
50-272/86-23  
The statement in Attachment B-2 to the November 7, 1986 letter with regard to the reasons for the clogging of the drains in FIRL Test Report F-C3441 were misinterpreted in that the drains were clogged with grease which had come out of the grease relief valve after the flooding of the test chamber. The grease actually came out of the relief valve prior to the flooding of the chamber. The grease used was not identified. This misinterpretation does not alter the overall analysis performed on the subject item and has been corrected in the "Revised Attachment B-2."
AND 50-311/86-23  
The grease referred to in the November 7, 1986 submittal, Mobil Grease 28, is used in the intermittent gear box (not the main gear box) and is valid for that application. The intermittent gear box has no grease relief valve. The grease used in the main gear box is EXXON Nebula EPO or EPl. Although it is not a synthetic lubricant like Mobil Greas~ 28, it has been evaluated and the results indicate that it would perform in a manner similar to that presented for Mobil Grease 28. Analysis of the in-containment post-accident conditions with respect to the warming of the gear box and the subsequent expansion of the grease have indicated that appreciable expansion would not occur and that the ~witch compartment would not be breached.
REVISED RESPONSE TO INSPECTION  
Also, the statement in the November 7, 1986 submittal with regard to "appreciable expansion" of the grease only occurring afier reaching the dropping point should not have been interpreted to mean that no expansion occurs until the dropping point is reached. It is understood that expansion will begin to occur upon the initial warming of the grease. To avoid any confusion, this statement has been withdrawn. A Revised Attachment B-2 is provided with this letter.
REPORT SALEM  
Please contact Mr. Bruce Preston at 609-339-5129 with any questions you may have* Your cooperation in this matter is appreciated.
STATION DOCKET NOS. 50-272 AND 50-311 meeting was held on  
Sincerely,
3, 1987 at NRC Region I to discuss our responses  
* Attachment
to those Salem EQ inspection  
 
findings subject to the 10CFR50.49  
Document Control Desk       3 2/13/87 C  Mr. D. C. Fischer Licensing Project Manager Mr. T. J. Kenny Senior Resident Inspector Dr. T. E. Murley Regional Administrator Region I
enforcement  
                                      - I
criteria delineated  
 
in Generic Letter 86-15. During the meeting, NRC staff representatives  
Revised Attachment B - 2 A potential enforcement item was identified by the NRC related to the absence of gear box grease reliefs on Limitorque actuators located in containment. The con~ention is that the gear box grease reliefs must be provided in the plant installation since they were installed in the Limitorque actuators subjected to the LOCA/MSLB test simulation. It is verbally stated by Limitorque that the relief valve provides for relief of grease and the pressure build-up which occurs due to thermal expansion at prolonged elevated temperatures.
were notified of changes to our previous responses (dated November 7, 1986 and December 15, 1986) to the subject inspection  
However, Limitorque also states in Report 80~58, pages 14 and 15, that "Limitorque actuators for Nuclear Plant applications are designed to operate in normal and accident conditions without depending on absolute sealing. In fact, the ambient is not absolutely restricted from entering the actuator. The seals, are of no importance for qualification and, therefore, require no consideration for the qualification".
report. Those changes are being formally submitted  
Mr. J. Drab of Limitorque stated in a telephone conversation with Ms. B. Horst of PSE&G on April 9, 1986, as documented in the Record of Verbal Discossions, "They are not an EQ require~ent and their absence does not adversely affect the qualification status of Limitorques", Mr. Drab and Limitorque have subsequently refused to issue this statement in a signed letter.
by this letter and its attachment.  
In FIRL test report F-C3441 prepared for Limitorque (used in their BWR Containment Report-60376A), it was identified that flooding of the test chamber occurred from a build up of steam condensate when the test chamber condensate trap became clogged.
We first request that our previous response to Potential  
This was attributed to a grease build up in the trap caused by grease that had evidently come out of the relief valve during the test. The test was stopped during the fifth day. Prior to the test discontinuation, the specimen had been subjected to 2, three hour transients at +340°F, 5 hours at +320°F and 4 1/2 days at
Enforcement/Unresolved  
+250°F.
Item 50-272/86-23-03:  
The Salem plant temperature profile for a Main Steamline Break (MSLB) shows a peak temperature of 347°F for 72 seconds, droppinq to approximately 260°F in less than 5 minutes. For a LOCA, a peak temperature of 268°F is reached and maintained for 12 1/2 minutes. Within 30 minutes the temperature will fall below 250°F. Each of these accidents produces a peak pressure of 43.2 psig for 170 minutes. Therefore, an external positive pressure is maintained for the duration of the temperature transient minimizing the pressure differential due to possible internal pressure buildup.
50-311/86-23-03  
da8/l
regarding  
 
the qualification  
' . The Superheat Temperature Test Report #B0027 was performed to determine the internal temperatures of components in the Limitorque valve actuators due to superheat ambient temperatures. It illustrates that exposure of the actuator to high environmental temperatures for short durations of time will not raise internal unit temperatures to an equal state. It was demonstrated by analysis that an*ambient temperature of 492°F in excess of 17 minutes would only result in a maximum internal temperature of 315°F for the electrical switch compartment components and motor windings. Actual testing indicates that an ambient temperature of 385°F was reached at 186 minutes and at this time the temperature inside the motor was only 282°F.
of Rockbestos  
It can therefore be concluded that the effects of high ambient temperatures over a short time period will not result in excessively high internal temperatures. As such, excessive internal pressure will not result.
EPR and Coaxial cahle be withdrawn.  
The grease utilized for lubrication of the intermittent gear box in the Limitorques at Salem is Mobil Grease 28. This. is a synthetic lubricant exhibiting high pressure characteristics at temperatures in excess of 350°F. This grease has a dropping point of approximately 500°F, which precludes its changing to a liquid state even under superheat conditions.
An in-depth review of our November 7_, 1986 response to this finding was performed  
The main gearbox utilizies a calcium complex base grease manufactured by Exxon and known as Nebula EPl (or EPO). This grease can be used for applications up to 400°F, it contains an Extreme Pressure (EP) additive to help increase the film strength of the oil, and has a dropping ~oint of approximately 500°F. The EPl grease exhibits similar characteristics to the Mobil 28 grease and both types of grease are approved by Limitorque for in-containment applications in the operators.
by PSE&G prior to the meeting at NRC Region I. The results of the review determined  
In Test Report B0003, an actuator containing Nebula EPl gearbox grease was exposed to a sustained temperature of 250°F for 24 hours. Grease relief valves were not installed on this actuator as Limitorque evidently determined that exposure to 250°F and 25 psig during an accident test was not sufficient to justify their usage ** The test unit actuator was a SMB-0 type, which is rather small, containing approximately 9.5 pounds of gearbox grease.
that although PSE&G EQ personnel  
Larger actuat9rs contain up to 75 pounds of grease (SMB-4 or 5 type). Given the small size of the test unit, it can be deduced that maintaining the temperature at 250°F for 24 hours will bring
were knowledgeable  
    .the entire unit to therma1 equilibrium, including the gearbox grease. It can therefore be determined that EPl type grease can be heated to 250°F and will not expand to any degree that would require the use of a grease relief on the actuator.
of the additional  
da8/2
tests which substantiated  
 
the results of the questionable  
... By utilizing the Salem accident profile for temperature and pressure for worst case Main Steam Line Break (MSLB) and Loss-of
Rockbestos  
    -Coolant Accident (LOCA), it can be determined by analysis that exposure to either condition inside containment will not cause the gearbox grease to exceed 250°F. This is due to the fact that the maximum LOCA temperature of 268°F is reached in approximately 4 minutes following the start of the accident, after which the temperature slowly begins to decrease. Thirty minutes following the start of the event the temperature has fallen below 250°F.
test reports noted in IE Information  
As is evident, the time duration is not sufficient to heat the grease above 250°F.
Notice 84-44, these test reports had not been formally analyzed and referenced  
During the MSLB event, a maximum temperature of 347°F is *reached in approximately 100 seconds. This temperature is maintained for 72 seconds, after which the temperature rapidly begins to decrease. Thirty minutes following the start of the event the temperature falls below 250°F. Again the time duration at the temperature above 250° is not sufficient to heat the grease above 250°F.
in the Rockbestos  
The characteristics of the grease would be a factor in determining the necessity of grease reliefs on the gear case housing. Since the greases utilized during the qualification tests were not identified, a correlation of actual parameters cannot be made. However, a temperature resistant grease such as the Nebula EPl appears to have been used.
EQ file. As such, the inspection  
As proven by test, the internal temperature of the operator, even un-der superheated ambient conditions, would not cause the internal temperature to exceed saturated conditions. This temperature is well within the design limits of the specified grease and would not be cause for it to exhibit appreciable expansion. A pressure buildup sufficient to breach tbe switch compartment is not possible under the Salem Station postulated accident conditions and therefore grease relief plugs are not required to maintain operability of the valve.
finding in this area is not disputed.  
It should be noted that PSE&G's position was, and still is, that a determination to not use grease reliefs was made from all known and available information. Based on the verbal information from Limitorque, the Salem PWR specific accident profiles and knowledge of the data in the test report; it was determined that the grease relief valves were not necessary; would not prevent the valves from performing their safety function; and their absence would not be in violation of the qualification status of the actuators.
The review of the response to Potential  
da8/3
Enforcement/Unresolved  
 
Item 50-272/86-23-04:  
  ~                                      .
50-311/86-21-04  
For information purposes, at the time of the inspection, there were 7 in-containment class lE actuators in Salem Unit 1 that were identified by Station QA personnel as not having grease
also uncovered  
*  . relief valves. Salem Unit 2 had grease relief valves installed on all in-containment actuators. In accordance with the recommendation to. utilize grease reliefs as good engineering practice, grease reliefs are now installed on all in-containment actuators at Salem.
certain *discrepancies  
da8/4}}
in the information  
presented  
with regard to the Limitorque  
gear case grease reliefs. Correction  
of these
Q * . ' * * Document Control Desk 2 2/13/87 discrepancies  
does not alter our position that tha grease reliefs were not required for the operability  
of the Limitorque  
operators  
in containment  
under Salem plant-specific  
post-accident  
conditions.  
The statement  
in Attachment  
B-2 to the November 7, 1986 letter with regard to the reasons for the clogging of the drains in FIRL Test Report F-C3441 were misinterpreted  
in that the drains were clogged with grease which had come out of the grease relief valve after the flooding of the test chamber. The grease actually came out of the relief valve prior to the flooding of the chamber. The grease used was not identified.  
This misinterpretation  
does not alter the overall analysis performed  
on the subject item and has been corrected  
in the "Revised Attachment  
B-2." The grease referred to in the November 7, 1986 submittal, Mobil Grease 28, is used in the intermittent  
gear box (not the main gear box) and is valid for that application.  
The intermittent  
gear box has no grease relief valve. The grease used in the main gear box is EXXON Nebula EPO or EPl. Although it is not a synthetic  
lubricant  
like Mobil  
28, it has been evaluated  
and the results indicate that it would perform in a manner similar to that presented  
for Mobil Grease 28. Analysis of the in-containment  
post-accident  
conditions  
with respect to the warming of the gear box and the subsequent  
expansion  
of the grease have indicated  
that appreciable  
expansion  
would not occur and that the  
compartment  
would not be breached.  
Also, the statement  
in the November 7, 1986 submittal  
with regard to "appreciable  
expansion" of the grease only occurring  
afier reaching the dropping point should not have been interpreted  
to mean that no expansion  
occurs until the dropping point is reached. It is understood  
that expansion  
will begin to occur upon the initial warming of the grease. To avoid any confusion, this statement  
has been withdrawn.  
A Revised Attachment  
B-2 is provided with this letter. Please contact Mr. Bruce Preston at 609-339-5129  
with any questions  
you may have* Your cooperation  
in this matter is appreciated.  
Sincerely, Attachment
Document Control Desk C Mr. D. C. Fischer Licensing  
Project Manager Mr. T. J. Kenny Senior Resident Inspector  
Dr. T. E. Murley Regional Administrator  
Region I 3 2/13/87 -I
Revised Attachment B -2 A potential  
enforcement  
item was identified  
by the NRC related to the absence of gear box grease reliefs on Limitorque  
actuators  
located in containment.  
The  
is that the gear box grease reliefs must be provided in the plant installation  
since they were installed  
in the Limitorque  
actuators  
subjected  
to the LOCA/MSLB  
test simulation.  
It is verbally stated by Limitorque  
that the relief valve provides for relief of grease and the pressure build-up which occurs due to thermal expansion  
at prolonged  
elevated temperatures.  
However, Limitorque  
also states in Report  
pages 14 and 15, that "Limitorque  
actuators  
for Nuclear Plant applications  
are designed to operate in normal and accident conditions  
without depending  
on absolute sealing. In fact, the ambient is not absolutely  
restricted  
from entering the actuator.  
The seals, are of no importance  
for qualification  
and, therefore, require no consideration  
for the qualification".  
Mr. J. Drab of Limitorque  
stated in a telephone  
conversation  
with Ms. B. Horst of PSE&G on April 9, 1986, as documented  
in the Record of Verbal Discossions, "They are not an EQ  
and their absence does not adversely  
affect the qualification  
status of Limitorques", Mr. Drab and Limitorque  
have subsequently  
refused to issue this statement  
in a signed letter. In FIRL test report F-C3441 prepared for Limitorque (used in their BWR Containment  
Report-60376A), it was identified  
that flooding of the test chamber occurred from a build up of steam condensate  
when the test chamber condensate  
trap became clogged. This was attributed  
to a grease build up in the trap caused by grease that had evidently  
come out of the relief valve during the test. The test was stopped during the fifth day. Prior to the test discontinuation, the specimen had been subjected  
to 2, three hour transients  
at +340°F, 5 hours at +320°F and 4 1/2 days at +250°F. The Salem plant temperature  
profile for a Main Steamline  
Break (MSLB) shows a peak temperature  
of 347°F for 72 seconds, droppinq to approximately  
260°F in less than 5 minutes. For a LOCA, a peak temperature  
of 268°F is reached and maintained  
for 12 1/2 minutes. Within 30 minutes the temperature  
will fall below 250°F. Each of these accidents  
produces a peak pressure of 43.2 psig for 170 minutes. Therefore, an external positive pressure is maintained  
for the duration of the temperature  
transient  
minimizing  
the pressure differential  
due to possible internal pressure buildup. da8/l
'< ' .. The Superheat  
Temperature  
Test Report #B0027 was performed  
to determine  
the internal temperatures  
of components  
in the Limitorque  
valve actuators  
due to superheat  
ambient temperatures.  
It illustrates  
that exposure of the actuator to high environmental  
temperatures  
for short durations  
of time will not raise internal unit temperatures  
to an equal state. It was demonstrated  
by analysis that an*ambient  
temperature  
of 492&deg;F in excess of 17 minutes would only result in a maximum internal temperature  
of 315&deg;F for the electrical  
switch compartment  
components  
and motor windings.  
Actual testing indicates  
that an ambient temperature  
of 385&deg;F was reached at 186 minutes and at this time the temperature  
inside the motor was only 282&deg;F. It can therefore  
be concluded  
that the effects of high ambient temperatures  
over a short time period will not result in excessively  
high internal temperatures.  
As such, excessive  
internal pressure will not result. The grease utilized for lubrication  
of the intermittent  
gear box in the Limitorques  
at Salem is Mobil Grease 28. This. is a synthetic  
lubricant  
exhibiting  
high pressure characteristics  
at temperatures  
in excess of 350&deg;F. This grease has a dropping point of approximately  
500&deg;F, which precludes  
its changing to a liquid state even under superheat  
conditions.  
The main gearbox utilizies  
a calcium complex base grease manufactured  
by Exxon and known as Nebula EPl (or EPO). This grease can be used for applications  
up to 400&deg;F, it contains an Extreme Pressure (EP) additive to help increase the film strength of the oil, and has a dropping  
of approximately  
500&deg;F. The EPl grease exhibits similar characteristics  
to the Mobil 28 grease and both types of grease are approved by Limitorque  
for in-containment  
applications  
in the operators.  
In Test Report B0003, an actuator containing  
Nebula EPl gearbox grease was exposed to a sustained  
temperature  
of 250&deg;F for 24 hours. Grease relief valves were not installed  
on this actuator as Limitorque  
evidently  
determined  
that exposure to 250&deg;F and 25 psig during an accident test was not sufficient  
to justify their usage ** The test unit actuator was a SMB-0 type, which is rather small, containing  
approximately  
9.5 pounds of gearbox grease. Larger actuat9rs  
contain up to 75 pounds of grease (SMB-4 or 5 type). Given the small size of the test unit, it can be deduced that maintaining  
the temperature  
at 250&deg;F for 24 hours will bring .the entire unit to therma1 equilibrium, including  
the gearbox grease. It can therefore  
be determined  
that EPl type grease can be heated to 250&deg;F and will not expand to any degree that would require the use of a grease relief on the actuator.  
da8/2
... * By utilizing  
the Salem accident profile for temperature  
and pressure for worst case Main Steam Line Break (MSLB) and Loss-of -Coolant Accident (LOCA), it can be determined  
by analysis that exposure to either condition  
inside containment  
will not cause the gearbox grease to exceed 250&deg;F. This is due to the fact that the maximum LOCA temperature  
of 268&deg;F is reached in approximately  
4 minutes following  
the start of the accident, after which the temperature  
slowly begins to decrease.  
Thirty minutes following  
the start of the event the temperature  
has fallen below 250&deg;F. As is evident, the time duration is not sufficient  
to heat the grease above 250&deg;F. During the MSLB event, a maximum temperature  
of 347&deg;F is *reached in approximately  
100 seconds. This temperature  
is maintained  
for 72 seconds, after which the temperature  
rapidly begins to decrease.  
Thirty minutes following  
the start of the event the temperature  
falls below 250&deg;F. Again the time duration at the temperature  
above 250&deg; is not sufficient  
to heat the grease above 250&deg;F. The characteristics  
of the grease would be a factor in determining  
the necessity  
of grease reliefs on the gear case housing. Since the greases utilized during the qualification  
tests were not identified, a correlation  
of actual parameters  
cannot be made. However, a temperature  
resistant  
grease such as the Nebula EPl appears to have been used. As proven by test, the internal temperature  
of the operator, even un-der superheated  
ambient conditions, would not cause the internal temperature  
to exceed saturated  
conditions.  
This temperature  
is well within the design limits of the specified  
grease and would not be cause for it to exhibit appreciable  
expansion.  
A pressure buildup sufficient  
to breach tbe switch compartment  
is not possible under the Salem Station postulated  
accident conditions  
and therefore  
grease relief plugs are not required to maintain operability  
of the valve. It should be noted that PSE&G's position was, and still is, that a determination  
to not use grease reliefs was made from all known and available  
information.  
Based on the verbal information  
from Limitorque, the Salem PWR specific accident profiles and knowledge  
of the data in the test report; it was determined  
that the grease relief valves were not necessary;  
would not prevent the valves from performing  
their safety function;  
and their absence would not be in violation  
of the qualification  
status of the actuators.  
da8/3   
. For information  
purposes, at the time of the inspection, there *were 7 in-containment  
class lE actuators  
in Salem Unit 1 that were identified  
by Station QA personnel  
as not having grease . relief valves. Salem Unit 2 had grease relief valves installed  
on all in-containment  
actuators.  
In accordance  
with the recommendation  
to. utilize grease reliefs as good engineering  
practice, grease reliefs are now installed  
on all in-containment  
actuators  
at Salem. da8/4
}}

Latest revision as of 08:04, 3 February 2020

Responds to Violations Noted in Insp Repts 50-272/86-23 & 50-311/86-23.Corrective Actions:Attachment B-2 Revised to Correct Misinterpretation of Grease Clogged Drains.Revised Attachment B-2 Encl
ML18092B435
Person / Time
Site: Salem  PSEG icon.png
Issue date: 02/13/1987
From: Corbin McNeil
Public Service Enterprise Group
To: Heishman R
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
GL-86-015, IEB-84-44, NLR-N87017, NUDOCS 8702260252
Download: ML18092B435 (7)
v • d • e


Text

' .

Public Service Electric and Gas Company Corbin A. McNeill, Jr. Public Service Electric and Ga? Company P 0. Box236. Hancocks Bridge. i\JJ 08038 609 339-4;300 V:ce Pres*cen:

  • February 13, 1987 NLR-N87017 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Attention: Mr. Robert F. Heishman, Chief Vendor Programs Branch Division of Quality Assurance Vendor and Technical Training Center Programs Off ice of Inspection and Enforcement Gentlemen:

NRC INSPECTION 50-272/86-23 AND 50-311/86-23 REVISED RESPONSE TO INSPECTION REPORT SALEM GENE~TING STATION DOCKET NOS. 50-272 AND 50-311

~ meeting was held on Fe~ruary 3, 1987 at NRC Region I to discuss our responses to those Salem EQ inspection findings subject to the 10CFR50.49 enforcement criteria delineated in Generic Letter 86-15. During the meeting, NRC staff representatives were notified of changes to our previous responses (dated November 7, 1986 and December 15, 1986) to the subject inspection report.

Those changes are being formally submitted by this letter and its attachment.

We first request that our previous response to Potential Enforcement/Unresolved Item 50-272/86-23-03: 50-311/86-23-03 regarding the qualification of Rockbestos EPR and Coaxial cahle be withdrawn. An in-depth review of our November 7_, 1986 response to this finding was performed by PSE&G prior to the meeting at NRC Region I. The results of the review determined that although PSE&G EQ personnel were knowledgeable of the additional tests which substantiated the results of the questionable Rockbestos test reports noted in IE Information Notice 84-44, these test reports had not been formally analyzed and referenced in the Rockbestos EQ file. As such, the inspection finding in this area is not disputed.

The review of the response to Potential Enforcement/Unresolved Item 50-272/86-23-04: 50-311/86-21-04 also uncovered certain discrepancies in the information presented with regard to the Limitorque gear case grease reliefs. Correction of these

Q *

. ' Document Control Desk 2 2/13/87

  • discrepancies does not alter our position that tha grease reliefs were not required for the operability of the Limitorque operators in containment under Salem plant-specific post-accident conditions.

The statement in Attachment B-2 to the November 7, 1986 letter with regard to the reasons for the clogging of the drains in FIRL Test Report F-C3441 were misinterpreted in that the drains were clogged with grease which had come out of the grease relief valve after the flooding of the test chamber. The grease actually came out of the relief valve prior to the flooding of the chamber. The grease used was not identified. This misinterpretation does not alter the overall analysis performed on the subject item and has been corrected in the "Revised Attachment B-2."

The grease referred to in the November 7, 1986 submittal, Mobil Grease 28, is used in the intermittent gear box (not the main gear box) and is valid for that application. The intermittent gear box has no grease relief valve. The grease used in the main gear box is EXXON Nebula EPO or EPl. Although it is not a synthetic lubricant like Mobil Greas~ 28, it has been evaluated and the results indicate that it would perform in a manner similar to that presented for Mobil Grease 28. Analysis of the in-containment post-accident conditions with respect to the warming of the gear box and the subsequent expansion of the grease have indicated that appreciable expansion would not occur and that the ~witch compartment would not be breached.

Also, the statement in the November 7, 1986 submittal with regard to "appreciable expansion" of the grease only occurring afier reaching the dropping point should not have been interpreted to mean that no expansion occurs until the dropping point is reached. It is understood that expansion will begin to occur upon the initial warming of the grease. To avoid any confusion, this statement has been withdrawn. A Revised Attachment B-2 is provided with this letter.

Please contact Mr. Bruce Preston at 609-339-5129 with any questions you may have* Your cooperation in this matter is appreciated.

Sincerely,

  • Attachment

Document Control Desk 3 2/13/87 C Mr. D. C. Fischer Licensing Project Manager Mr. T. J. Kenny Senior Resident Inspector Dr. T. E. Murley Regional Administrator Region I

- I

Revised Attachment B - 2 A potential enforcement item was identified by the NRC related to the absence of gear box grease reliefs on Limitorque actuators located in containment. The con~ention is that the gear box grease reliefs must be provided in the plant installation since they were installed in the Limitorque actuators subjected to the LOCA/MSLB test simulation. It is verbally stated by Limitorque that the relief valve provides for relief of grease and the pressure build-up which occurs due to thermal expansion at prolonged elevated temperatures.

However, Limitorque also states in Report 80~58, pages 14 and 15, that "Limitorque actuators for Nuclear Plant applications are designed to operate in normal and accident conditions without depending on absolute sealing. In fact, the ambient is not absolutely restricted from entering the actuator. The seals, are of no importance for qualification and, therefore, require no consideration for the qualification".

Mr. J. Drab of Limitorque stated in a telephone conversation with Ms. B. Horst of PSE&G on April 9, 1986, as documented in the Record of Verbal Discossions, "They are not an EQ require~ent and their absence does not adversely affect the qualification status of Limitorques", Mr. Drab and Limitorque have subsequently refused to issue this statement in a signed letter.

In FIRL test report F-C3441 prepared for Limitorque (used in their BWR Containment Report-60376A), it was identified that flooding of the test chamber occurred from a build up of steam condensate when the test chamber condensate trap became clogged.

This was attributed to a grease build up in the trap caused by grease that had evidently come out of the relief valve during the test. The test was stopped during the fifth day. Prior to the test discontinuation, the specimen had been subjected to 2, three hour transients at +340°F, 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> at +320°F and 4 1/2 days at

+250°F.

The Salem plant temperature profile for a Main Steamline Break (MSLB) shows a peak temperature of 347°F for 72 seconds, droppinq to approximately 260°F in less than 5 minutes. For a LOCA, a peak temperature of 268°F is reached and maintained for 12 1/2 minutes. Within 30 minutes the temperature will fall below 250°F. Each of these accidents produces a peak pressure of 43.2 psig for 170 minutes. Therefore, an external positive pressure is maintained for the duration of the temperature transient minimizing the pressure differential due to possible internal pressure buildup.

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' . The Superheat Temperature Test Report #B0027 was performed to determine the internal temperatures of components in the Limitorque valve actuators due to superheat ambient temperatures. It illustrates that exposure of the actuator to high environmental temperatures for short durations of time will not raise internal unit temperatures to an equal state. It was demonstrated by analysis that an*ambient temperature of 492°F in excess of 17 minutes would only result in a maximum internal temperature of 315°F for the electrical switch compartment components and motor windings. Actual testing indicates that an ambient temperature of 385°F was reached at 186 minutes and at this time the temperature inside the motor was only 282°F.

It can therefore be concluded that the effects of high ambient temperatures over a short time period will not result in excessively high internal temperatures. As such, excessive internal pressure will not result.

The grease utilized for lubrication of the intermittent gear box in the Limitorques at Salem is Mobil Grease 28. This. is a synthetic lubricant exhibiting high pressure characteristics at temperatures in excess of 350°F. This grease has a dropping point of approximately 500°F, which precludes its changing to a liquid state even under superheat conditions.

The main gearbox utilizies a calcium complex base grease manufactured by Exxon and known as Nebula EPl (or EPO). This grease can be used for applications up to 400°F, it contains an Extreme Pressure (EP) additive to help increase the film strength of the oil, and has a dropping ~oint of approximately 500°F. The EPl grease exhibits similar characteristics to the Mobil 28 grease and both types of grease are approved by Limitorque for in-containment applications in the operators.

In Test Report B0003, an actuator containing Nebula EPl gearbox grease was exposed to a sustained temperature of 250°F for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Grease relief valves were not installed on this actuator as Limitorque evidently determined that exposure to 250°F and 25 psig during an accident test was not sufficient to justify their usage ** The test unit actuator was a SMB-0 type, which is rather small, containing approximately 9.5 pounds of gearbox grease.

Larger actuat9rs contain up to 75 pounds of grease (SMB-4 or 5 type). Given the small size of the test unit, it can be deduced that maintaining the temperature at 250°F for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> will bring

.the entire unit to therma1 equilibrium, including the gearbox grease. It can therefore be determined that EPl type grease can be heated to 250°F and will not expand to any degree that would require the use of a grease relief on the actuator.

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... By utilizing the Salem accident profile for temperature and pressure for worst case Main Steam Line Break (MSLB) and Loss-of

-Coolant Accident (LOCA), it can be determined by analysis that exposure to either condition inside containment will not cause the gearbox grease to exceed 250°F. This is due to the fact that the maximum LOCA temperature of 268°F is reached in approximately 4 minutes following the start of the accident, after which the temperature slowly begins to decrease. Thirty minutes following the start of the event the temperature has fallen below 250°F.

As is evident, the time duration is not sufficient to heat the grease above 250°F.

During the MSLB event, a maximum temperature of 347°F is *reached in approximately 100 seconds. This temperature is maintained for 72 seconds, after which the temperature rapidly begins to decrease. Thirty minutes following the start of the event the temperature falls below 250°F. Again the time duration at the temperature above 250° is not sufficient to heat the grease above 250°F.

The characteristics of the grease would be a factor in determining the necessity of grease reliefs on the gear case housing. Since the greases utilized during the qualification tests were not identified, a correlation of actual parameters cannot be made. However, a temperature resistant grease such as the Nebula EPl appears to have been used.

As proven by test, the internal temperature of the operator, even un-der superheated ambient conditions, would not cause the internal temperature to exceed saturated conditions. This temperature is well within the design limits of the specified grease and would not be cause for it to exhibit appreciable expansion. A pressure buildup sufficient to breach tbe switch compartment is not possible under the Salem Station postulated accident conditions and therefore grease relief plugs are not required to maintain operability of the valve.

It should be noted that PSE&G's position was, and still is, that a determination to not use grease reliefs was made from all known and available information. Based on the verbal information from Limitorque, the Salem PWR specific accident profiles and knowledge of the data in the test report; it was determined that the grease relief valves were not necessary; would not prevent the valves from performing their safety function; and their absence would not be in violation of the qualification status of the actuators.

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For information purposes, at the time of the inspection, there were 7 in-containment class lE actuators in Salem Unit 1 that were identified by Station QA personnel as not having grease

  • . relief valves. Salem Unit 2 had grease relief valves installed on all in-containment actuators. In accordance with the recommendation to. utilize grease reliefs as good engineering practice, grease reliefs are now installed on all in-containment actuators at Salem.

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