ML20215C888
| ML20215C888 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 09/30/1986 |
| From: | Withers B PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20215C726 | List: |
| References | |
| TAC-63157, NUDOCS 8610100513 | |
| Download: ML20215C888 (12) | |
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f o-1 PORTLAND CENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LICHT COMPANY Operating License NPF-1 Docket 50-344 License Change Application 142 This License Change Application requests modifications to Appendix A of Operating License NPF-1 for the Trojan Nuclear Plant regarding control room habitability by proposing changes to:
(1) TTS 3/4.3.3.6, Chlorine Detection Systems; (2) TTS 3/4.3.3.12 SO2 Detection Systems; and (3) TTS 3/4.7.6.1, Control Room Emergency Ventilation System.
PORTLAND GENERAL ELECTRIC COMPANY By
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Bart D. Withers Vice President Nuclear Subscribed and sworn to before me this 30th day of September 1986.
OMyCommission k
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Notary Public of Ore ((on
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8610100513 860930 DR ADOCK 0500 4
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A LCA 142 Page 1 of 11 DESCRIPTION OF CHANGE-The following changes to the Trojan Technical Specifications (TTS) are proposed:
1.
TTS 3.3.3.6, Chlorine Detection Systems - This TTS is revised to be applicable in ALL MODES instead of MODES 1 through 4.
- Also, reference to the detectors being located in the control room duct is deleted.
2.
TTS 3/4.3.3.12, S02 Detection Systems - This TTS and associated Bases are deleted.
3.
TTS 3/4.7.6.1, Control Room Emergency Ventilation System (CB-1) -
This TTS is revised to:
(a) be applicable in ALL NODES, (b) incorporate the ACTION statement from the W-STS'(NUREG-0452 Rev. 4), (c) perform a monthly flow test for 15 minutes, (d) reduce the frequency of the monthly cooling capability 2
test to annually, (e) increase the HEPA and charcoal filter test efficiency to 199.95 percent from 1.99 percent, (f) specify a system flow rate of 3000 cfm, (g) incorporate the Regulatory Guide 1.52 test guidelines for laboratory charcoal analysis, (h) delete reference to an S02 signal for control room isolation, and (i) perform testing every 18 months to demonstrate a positive pressure can be maintained relative to adjacent spaces.
The above changes are shown in Attachment 1.
I REASON FOR CHANGE In References 1 through 3. PGE committed to evaluate the TTS that affect
' control room habitability. This evaluation was committed to based on NRC inspections of Trojan in January and February 1986, and a series of dis-i cussions and meetings held subsequent to these inspections. Our evalua-tion has concluded that changes to the TTS are needed as identified above and further described below.
1.
TTS 3.3.3.6, Chlorine Detection Systems - The change to make this TTS applicable in ALL NODES conforms with the W-STS (NUREG-0452, Rev. 4) and provides greater assurance of protection for the control room operators from chlorine gas releases. The change t
deleting reference to the chlorine detectors as being in the L
intake ducts is done for consistency since the detectors are located immediately outside the normal intake location.
2.
TTS 3/4.3.3.12, SO2 Detection Systems - This TTS is being deleted because the revised toxic gas analysis provided in Reference 4 justifies deletion of the SO2 detectors.
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a LCA 142 Page 2 of 11 J
3.
TTS 3/4.7.6.1, Control Room Emergency Ventilation System - The change to make this TTS. applicable in ALL MCDES conforms with the M-STS (NUREG-0452, Rev. 4),and provides greater assurance the control room will remain habitable. The change to incorporate the M-STS ACTION is done to provide ACTION statements for MODES 5 and 6, for which there previously were none, to be consistent with the above change in APPLICABILITY to ALL MODES.
The change to Surveillance Requirement 4.7.6.1.a and the addition of Surveillance Requirement 4.7.6.1.b are proposed because the CB-1 system prehesters (VE-161A & B, FSAR Figure 9.4-1) are to be disconnected and no longer utilized. As discussed in Reference 1, PGE committed to perform an evaluation of the need for the preheaters. The complete evaluation is provided in Reference 5.
The results of this evaluation demonstrate that the humidity of the air entering the CB-1 filtration unit is
<70 percent under any condition. Since the air entering the CB-1 flitration unit is <70 percent relative humidity, there is no need to utilize the preheaters to control the humidity to
<70 percent.
The deletion of the preheaters is reflected in the TTS by the proposed change to Surveillance Requirement 4.7.6.1.a and the addition of Surveillance Requirement 4.7.6.1.b.
The proposed Surveillance Requirement 4.7.6.1.a deletes the requirement to perform a monthly 10-hour test with the preheaters on.
Instead a monthly test for 15 minutes will be performed to ensure that CB-1 starts and initiates flow through the system. Since the preheaters are to be deleted, the provision in Regulatory Guide 1.52 Position C.4.d, to operate each Engineered Safety Feature I
(ESP) HVAC system for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month with the preheaters on is no longer applicable. Therefore, the test duration of 15 minutes is proposed. The proposed test duration of 15 minutes is the same as similar tests performed on the spent fuel exhaust system (TTS 4.9.12.2), the Containment Cooling System (TTS 4.6.2.3.a.2), and the Hydrogen Vent System (TTS 4.6.4.3.a).
In addition, the proposed test duration and frequency is the same as similar tests performed on the Control Room Emergency Ventilation System at other nuclear plants where preheaters are not utilized.
The proposed Surveillance Requirement 4.7.6.1.b requires perfor-mance of an annual test of the capability of CB-1 to maintain the control room <110*F.
This test differs from the current test in that the preheaters are not required to be on since they are to
r LCA 142 Page 3 of 11 l
be deleted. In addition, this change proposes to reduce the test frequency from monthly to annually.
The basis for reducing the test frequency is twofold. First, since the preheaters are to be deleted, the monthly test to dry-out the charcoal adsorbers required by Regulatory Guide 1.52 discussed above is no longer necessary. Secondly, an annual test is dermed adequate to determine if the cooling capability of CB-1 has degraded.
In conjunction with the above requested change in test frequency, control room temperature testing is to be completed by the end.of this year. This test program consists of locating thermoccuples throughout numerous control room' cabinets. The thermocouples input to a computerized data acquisition system. Testing will be performed during operation of CB-1 and CB-2 to identify temperature sensitive cabinets and determine the extent of heat-up in these cabinets. The test results will be used in determining the effectiveness of cabinet modifications to improve local ventilation and components which may be subject to accelerated thermal aging.
In addition, control room cooling modifications are being evaluated. These modifications and a schedule for implementation are provided in Reference 6.
The change to specify a total flow rate for CB-1 of 3000 cfm ensures that the residence time for radioactivity in the filter units is 1 25 seconds as assumed in the control room dose cal-0 culations.
The change to increase the HEPA filter and charcoal filter test removal efficiency to 99.95 percent conforms with the M-STS (NUREG-0452, Revision 4) and Regulatory Guide 1.52.
In addition, this will make the TTS consistent with the assumptions in the control room dose calculations.
The change to incorporate the Regulatory Guide 1.52 test require-ments for laboratory charcoal analysis into the TTS conforms with the M-STS (NUREG-0452, Rev. 4).
In addition, this will make the TTS consistent with the assumptions in the control room dose calculations.
The change which deletes reference to the SO2 signal in TTS 4.7.6.1.d.2 is done to be consistent with the deletion of the SO2 detectors and associated TTS 3/4.3.3.12, as previously discussed.
The change to TTS 4.7.6.1.d.3 to demonstrate a positive pressure is maintained to adjacent spaces provides assurance that unfiltered inleakage into the control room is minimized, consistent with the control room dose calculation.
LCA 142 Page 4 of 11 SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION TTS 3.3.3.6. Chlorine Detection Systems - Detectors OPERABLE in ALL MODES. This change does not involve a significant increase in the proba-
-bility or consequences of an accident because the change is a more restrictive limitation not presently included in the TTS.
Requiring the chlorine detectors to be OPERABLE in ALL NODES does not change the probability of an accident. However, it does reduce the probability of the detectors being inoperable when needed.to respond to a chlorine release because the proposed change requires OPERABILITY in ALL MODES J
instead of just MODES 1 through 4.
This in turn reduces the consequences
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of a chlorine release accident because the detectors will be OPERABLE to respond in MODES 5 and 6, when previously they were not required to be OPERABLE.
This change does not create the possibility of a new or different kind of accident because OPERABILITY of the chlorine detectors is not relevant to accident creation since they function to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because requiring the chlorine detectors to be OPERABLE in ALL MODES instead of only MODES 1 through 4 enhances safety.
TTS 3.3.3.6. Chlorine Detection Systems - Detectors located immediately outside normal intake location. This change does not involve a significant increase in the probability or consequences of an accident because it is an administrative change. The present TTS implies that the
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chlorine detector is physically located in the duct. In actuality, the detectors and sensor tubing inlet are located immediately outside the normal makeup air intake location.
This change does not create the possibility of a new or different kind of accident because the location of the chlorine detectors is not relevant to accident creation since they function to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because this change is administrative.
TTS 3/4.3.3.12, S09 Detection Systems - Deletion of this TTS.
This change does not involve a significant increase in the probability or consequences of an accident because OPERABILITY of the S02 detectors is not relevant to accident probability. The purpose of the SO2 detectors is to mitigate the consequences of an accident after it has occurred. The consequences of an SO2 release have been evaluated in Reference 4.
This evaluation demonstrates that automatic isolation of 5
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LCA 142 Page 5 of 11 the control room outside air supply is not required in the event of an 30' release. Because control room operators have adequate time to don 2
self-contained breathing apparatus and manually isolate the control room outside air supply in the event of an SO2 release, this change does not increase the consequences of an accident.
This change does not create the possibility of a new or different kind detectors is not relevant to of accident because OPERABILITY of the SO2 accident creation since they function to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety, because as demonstrated in Reference 4, control room operators have adequate time to don self-contained breathing apparatus and manually isolate the control room outside air supply in the event of an SO2 release.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - CB-1 OPERABLE in ALL MODES. This change does not involve a significant increase in the probability or consequences of an accident because the change is a more restrictive limitation not presently included in the TTS.
Requiring CB-1 to be OPERABLE in ALL MODES does not change the probability of an accident. However, it does reduce the probability of CB-1 being inoperable when needed to respond to an accident because the proposed change requires OPERABILITY in ALL MODES instead of just MODES 1 through 4.
This in turn reduces the consequences of an accident because CB-1 will be OPERABLE to respond in MODES 5 and 6, when previously it was not required to be OPERABLE.
This change does not create the possibility of a new or different kind of accident because OPERABILITY of CB-1 is not relevant to accident creation since it functions to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because requiring CB-1 to be OPERABLE in ALL MODES instead of only MODES 1 through 4 onhances safety.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Incorporate W-STS ACTION statements.
This change does not involve a significant increase in the probability or consequences of an accident because the change is a more restrictive limitation not presently included in the TTS.
Presently, there are no ACTION statements for this TTS in MODES 5 and 6 because OPEPABILITY is only required in MODES 1 through 4.
How-ever, to'be consistent with the change above which requires OPERABILITY in ALL MODES, the additional ACTION statements for MODES S and 6 are proposed.
4 LCA 142 Page 6 of 11 This change does not create the possibility of a new or different kind of accident because.0PERABILITY of CB-1 is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because providing the additional ACTION statements for MODES 5 and 6 enhances safety since there previously was no action required in these MODES.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Performance of a monthly flow test for 15 minutes. This change does not involve a significant increase in the probability or consequences of an accident.
The surveillance performed on CB-1 to demonstrate system OPERABILITY does not affect accident probability because CB-1 functions to mitigate the consequences of an accident after it has occurred. The consequences of an accident are not significantly increased sines the test frequency is unchanged. Furthermore, the purpose of this test is to establish flow through the CB-1 filtration unit. Since the preheaters are to be deleted, the provision in Regulatory Guide 1.52 to operate each ESF HVAC system for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month with the heaters on is no longer appli-cable. Therefore, the test duration of 15 minutes is proposed which is (1) an adequate duration to determine that flow has been established, and (2) the same duration as similar tests performed on the spent fuel pool exhaust system (TTS 4.9.12.2), the containment Cooling System 4
(TTS 4.6.2.3.a.2), and the Hydrogen Vent System (TTS 4.6.4.3.a).
This change does not create the possibility of a new or different kind 4
of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions 4
to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because the ability to establish flow through CB-1 in the same manner and at the same frequency as the existing TTS is still demon-strated.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Reduction in CB-1 cooling test frequency. This change does not involve a significant increase in the probability or consequences of an accident. The surveil-
' lance performed on CB-1 to demonstrate system OPERABILITY does not affect accident probability because CB-1 functions to mitigate the consequences of an accident after it has occurred. The consequences of an accident could be affected if CB-1 was unable to maintain the design basis temper-ature. Therefore, testing to demonstrate that CB-1 can maintain the control room 1110*F is prudent. However, the current TTS requiring a monthly cooling test instead of the proposed annual test is considered to be an excessive test frequency for the following reasons:
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LCA 142 Page 7 of 11 1.
Since the preheaters are to be deleted, the provision in Regulatory cuide 1.52 to operate each ESF HVAC system for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month is no longer applicable.
2.
The current monthly testing contributes to control room equipment aging.
CB-1 was not designed to keep the control room at 75'F like the normal control room ventilation system (CB-2).
The elevated control room temperature experienced during testing of CB-1, while well within design limits, is considered more detrimental to control room habitability than the marginal increase in cor.f1dence in CB-l's cooling ability provided by frequent monthly testing.
3.
Modes of possible failure of the CB-1 service water coolers, such as fouling do not occur rapidly enough to justify testing on a monthly basis. Annual testing is considered adequate to detect any decrease in the capacity of the service water coolers.
In addition, since testing is proposed on a STAGGERED TEST BASIS, at least one train of CB-1 will be tested every 6 months. There-fore, any significant degradation in the cooling capability of one trrain would result in investigations being performed on the other train. Since it is unlikely that significant degradation in the cooling capability of one train, e.g.,
fouling, would occur without also occurring in the other train, the effective sur/veillance frequency is equivalent to every 6 months.
G 4.
CB-1 has never failed to maintain temperature within design con-ditions during all testing performed to date. Test results show that the control room temperature has never exceeded approxi-mately 87'F during summer conditions. This is significantly less than the design basis of 110*F and indicates that gradual degradation of the CB-1 cooling capability between tests could be accommodated with available margin.
5.
The proposed monthly flow tests performed in accordance with TTS 4.7.6.1.a would provide indication of a major failure in the capability of CB-1 to cool the control room. This would prompt immediate corrective investigation.
This change does not create the possibility of a new or different kind of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because no change to the Limiting Condition for Operation nor control room design basis temperature is proposed.
Based on the above, this change does not pose a significant hazard.
4 LCA.142 Page 8 of 11 TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Reduction in CB-1 flow rate to 3000 cfm. This change does not involve a significant, increase-in the probability or consequences of an accident. The surveil-lance performed on CB-1 to demonstrate system OPERABILITY does not. affect accident probability because CB-1 functions to mitigate the consequences of an accident after it has occurred. The consequences of an accident are not significantly increased because the reduction in CB-1 flow rate to 3000 cfm ensures that the residence time for radioactivity in the filter units is 10.25 seconds as assumed in the control room dose calcu-lations.
This change dose not create the possibility of a new or different kind of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
2 This change does not involve a significant reduction in a margin of safety.because flow will still be established through CB-1 in the same manner and at the same frequency as the existing TTS, albeit at a slightly lower flow rate. Based upon past measurements, flow rates have actually been about 3000 cfm. Therefore, the lower specified flow rate of 3000 cfm is no different than actual performance of CB-1.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Increased HEPA and charcoal filter test efficiency. This change does not involve a significant increase in the probability or consequences of an accident because this change is a more restrictive limitation not presently included in the TTS.
This change imposes more restrictive requirements en the removal of particulates by the HEPA and charcoal filters.
This change does not create the possibility of a new or different kind of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
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This change does not involve a significant reduction in a margin of i
safety because testing the HEPA and charcoal filters to demonstrate a greater efficiency in the removal of particulates increases the margin between the as-tested and as-analyzed performance of the filters.
TTS 3/4.7.6.1. Control Room Emermancy Ventilation System - Revised labo-ratory charcoal analysis.
This change does not involve a significant increase in the probability or consequences of an accident because this changa is a more restrictive limitation not presently included in the TTS.
This change imposes more restrictive requirements on the removal efficiency of radioiodine by the charcoal adsorbers and also imposes more restrictive test conditions.
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LCA 142 Page 9 of 11 This change does not create the possibility of a new or different kind of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because subjecting the charcoal adsorbers to more restrictive test conditions and operating efficiencies increases the margin between the as-tested and as-analyzed performance of the filters.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Deletion of SO2 signals. This change does not involve a significant increase in the probability or consequences of an accident because OPERABILITY of the SO2 detectors is not relevant to accident probability. The purpose of the 302 detectors is to mitigate the consequences of an accident after it has occurred. The consequences of an SO2 release have been evaluated in Reference 4.
This evaluation demonstrates that automatic isolation of the control room outside air supply is not required in the event of an SO2 release. Because control room operators have adequate tioe to don self-contained breathing apparatus and manually isolate the control room outside air supply in the event of an S02 release, this change does not increase the consequences of an accident.
This change does not create the possibility of a new or different kind of accident because OPERABILITY of the SO2 detectors is not relevant to accident creation since they function to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety because as demonstrated in Reference 4, control room operators have adequate time to don self-contained breathing apparatus and manually isolate the control room outside air supply in the event of an SO2 release.
TTS 3/4.7.6.1. Control Room Emergency Ventilation System - Positive pres-sure relative to adjacent spaces. This change does not involve a signi-ficant increase in the probability or consequences of an accident because this change is a more restrictive limitation not presently included in the TTS.
The surveillance performed on CB-1 to demonstrate system OPERABILITY does not affect accident probability because CB-1 functions to mitigate the consequences of an accident after it has occurred. The consequences of an accident are not significantly increased because main-taining a control room positive pressure relative to adjacent spaces as opposed to only outside air provides greater assurance that unfiltered inleakage into the control room is minimized.
9 LCA 142 Page 10 of 11 This change does not create the possibility of a new or different. kind of accident because the surveillance performed on CB-1 to demonstrate OPERABILITY is not relevant to accident creation since CB-1 functions to mitigate the consequences of an accident after it has occurred.
This change does not involve a significant reduction in a margin of safety, but rather involves an enhancement of safety since the proposed change requires a positive pressure be maintained relative to adjacent spaces as opposed to the existing TTS which only requires maintaining a positive pressure relative to outside air. Maintaining a positive pressure in the control room in relation to adjacent spaces provides assurance that radioactivity which may enter adjacent spaces following an accident is prevented from entering the control room.
In the April 6, 1983 Federal Remister, the NRC published a list of examples of amendments that are not likely to involve a significant hazards consideration. Example No. 2 from this list states:
4 "A change that constitutes an additional limitation, restriction, or control not presently included in the technical specifications, eg, a more stringent surveillance requirement".
This example applies to the following proposed changes:
]
1.
Requiring the chlorine detectors to be OPERABLE in ALL MODES, 2.
Requiring CB-1 to be OPERABLE in ALL MODES, 3.
Implementing ACTION statements for CB-1 in MODES 5 and 6, l
4.
Increasing the HEPA and charcoal filter test efficiency, 5.
Specifying a CB-1 flow rate of 3000 cfm, 6.
Incorporating the Regulatory Guide 1.52 charcoal testing guide-lines and, 7.
Maintaining a control room positive pressure relative to adjacent spaces.
Based on the above evaluation, these changes do not pose a significant i
hazard.
Example No. 6 from the above cited Federal Register listing states:
l "A change which either may result in some increase to the probability or consequences of a previously analyzed accident or may reduce in
LCA 142 Page 11 of 11 some way a safety margin, but whers the results of the change are clearly within all acceptable criteria with respect to the system or component specified in the Standard Review Plan, e.g., a change resulting from the application of a small refinement of a previously used calculational model or design method."
This example applies to the following proposed changes:
1.
Deletion of the SO2 detectors, and 2.
Deletion of automatic isolation of the control room HVAC upon high SO -
2 Based on the above evaluation, these changes do not pose a significant hazard.
Example No. 1 from the above cited Federal Register listing states:
"A purely administrative change to technical specifications, eg, a change to achieve consistency throughout the technical specifica-
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tions, correction of an error, or a change in nomenclature."
This example applies to the following proposed changes:
4 1.
Correction of the chlorine detector location, and 2.
Performance of a monthly CB-1 flow test for 15 minutes, Based on the above evaluation, these changes do not pose a significant hazard.
REFERENCES 1.
PGE to NRC letter regarding control room habitability, May 19, 1936.
2.
PGE to NRC letter regarding CB-1 action plan, June 4, 1986.
3.
PGE to NRC letter regarding CB-1 action plan, June 13, 1986.
4.
Bechtel to PGE letters regarding toxic chemical study, June 10 and September 19, 1986.
5.
Bechtel to PGE letter regarding CB-1 preheaters, July 18, 1986.
6.
PGE to NRC letter regarding control room habitability design changes, September 30, 1986.
BLK/djh 1008W.0786
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