ML20113H627
| ML20113H627 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 07/27/1992 |
| From: | Chrzanowski D COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20113H628 | List: |
| References | |
| NUDOCS 9208050110 | |
| Download: ML20113H627 (7) | |
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July 27,1992 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulato Commission Washington, DC 2055 Attention: Document Control Desk =
Subject:
Byron Units 1 and 2, Application for Amendment to Facility Operating Licenses NPF-37 and NPF-66 NRC Docket Numbers 50-454 and 50-455
Dear Dr. Murley:
. Pursuant to 10 CFR 50.90 Commonwealth Edison (CECO) proposes to amend Appendix A, Technical Specifications of Facility Operating Licensas NPF-37 and NFP-66. The proposed amendment requests a change to Technical Specifications 3/4.7.6,3/4.7.7 and 3/4.9.12 to change ventilation flowrates, a heater dissipation rate, clarify a testing method, correct a ty:>ographical error and delete a footnote
- reference that is no longer applicable. CECO requests approval of this amendment in time for a June 1993 implementation.
' This proposed amendment request is subdivided as follows:
- 1. Attachment A gives a description and summary of the proposed changes in this amendment.
- 2. Attachment B includes the marked up Technical Specification pages with the requested changes indicated.
- 3. Attachment C describes Edison's evaluation performed in accordance with 10 CFR 50.92(c), which confirms that no significant hazards consideration is involved.
' 4. Attachment D provides the Environmental Assessment.
.This proposed amendment has been reviewed and aaproved by CECO On site and Off-site Review in accordance with Commonwealth Ecison procedures.
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Dr. T.E. Murley July 27,1992 To the best of my knowledge and belief, the statements contained in this
- document are true and correct. In some respects these statements are not based on my personal knc uledga, but on information furnished by other CECO employses, contractor employees, and/or cc,, suhants. Such information has been reviewed in accordance with company practice, and i believe it to be reliable.
CECO is notifying the State of Illinois of this application for amendment by transmitting a copy of this letter and its attachments to the designated State _ Official.
Please direct any questions you may have concerning this submittal to this office.
Sincerely, D.\
David J. Chrzanowski Nuclear Licensing Administrator Attachments: A Description and summary of the proposed changes B Marked-up Technical Specification pages C Evaluation of Significant Hazards Consideration D - Environmental Assessmerd cc: A. Bert Davis, Regional Administratoi Rill J. Hickman, Project Manager-NRR/PDill 2 W. Kropp, Senior Resident inspector (Byron)
Office of Nuclear Facility -IDNS
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- + ATTACHMENT A DESCRIPT)ON AND IMPACT GF PROPOSED CHANGES Summary _olthe_fuposedShanges c .The prooosed Technical Specification surveillance requirement 4.7.6.e.4 changes the acceptance value of the control room ventilation heater dissipation rate from 27.2 i
- 2.7 kW to greater than or equal to 24.0 kW. Changes are also proposed to Technical
'i Specification 3/4.7.7 to revise the nonaccessible area exhaust filter plenum system total flow rate from 66,900 cfm 210% to between 55,669 cfm and 68,200 cfm, and to delete the periodic bank flow rate test recuirements. Editorial changes are proposed to delete the._"*" and associated footnotes', and to correct a tymgraphical error.
Finally, in Technical Specification Surveillances 4.7.7.b.4 anc 4.9.12.b.4, the " cold DOP" testing requirement is being changed to require only "DOP testing". The marked ua Technical _ Specification pages indicating the pronosed changes are -
provided in Attachment B. A discussion of each change follows.
DelailedRescriptiottolthtLPapposedEbanges 1 Control Roc,m Ventilation Heater Dissipation .
DescaptiottandRaaes.olthe&prtantBeq uirement
-The current Technical Specification surve llance requirement 4.7.6.e.4 stipulates that verification of the control room ventilation heater dissipailon be performed every 18 months. The heaters are to dissipate 27.2 i 2.7 kW when
- tested in accordance with ANSI N510-1980, Testing of Nuclear. Air Cleaning-systems. UFSAR subsection 6.5.1.2.1.d.2 states that the emergency makeup air filter unit electric heaters are presently sized to reduce the humidity of the airstream to at least 70% relative humidity for the worst inlet conditions. For saturated air conditions ranging from -10 F to _104'F, a peak heating requirement of 27.2 kW (92,860 Btu /hr) was calculated.
DescdptiottsndEases of the Bequested Redaion The proposed amendment changes the control room ventilation heater dissipation rate to be greater than or equal to 24.0 kW. This rate is based on engineering analyses to determine the minimum heater dissipation to satisfy
' ANSI N509-1976 (Nuclear Power Plant Air Cleaning Units and Components) requirements and to fulfill the safety function. This document provides standards for design of air cleaning units.-
The turbine building air is the emergency source of the suction for the control room emergency air filter units The air within the turbine building was assumed to be identical with the atmospheric conditions for the design basis-accident condition. This' assumption is acceptabla based on NRC Meeting -
Report #50-456/88012(DRSS) that discusses an enforcement conference with Braidwood Station held in March,1988.
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Two calculations were performed to determine the most conservative worst case value. The first calculation uses actual worst case atmospheric periods that were identified by reviewing climatological data for a 20 year period and
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averaging them to obtain a statistically derived base, A minimum heater capacity M 21.1 kW was calculated to reduce the inlet air to 70% relative hum'dity .5ing this base and 110% of the design airflow rate.
The second calculation, which was more conservative, used UFSAR data to determine the worst case condition. The UFSAR outdoor design temperature given in Table 3.11-2 was used as the entering air temoerature. A minimum heater capacity of 23.8 kW was calculated using 110%'of the design air flow, and assurr ing the entering air is at 95*F and 100% relative humidity. Using a minimum heater capacity of 24.0 kW provides flexibility in performing the Technical Specification surveillance while satisfying the design function. ,
impactottinLP1pposed_ Change There is no impact on plant operation or the accident analyses in the UFSAR.
The control room emergency makeup air filter unit heaters are able to limit the relative humidity to 70% for the air entering the adsorbers in accordance with the design criteria of ANSI N509-1976. This optimizes filter efficiency. The changes do not affect the system's ability to perform its for .Jon of maintaining environmental conditions for selected equipment and histrumentation and maintaining the control room habitable following all credible accident conditions. 4
- 2. Nonaccessible Area Exhaust Fitter Plenum System Flow Rate Descnption_and Bases otthe_ Current Requirement The nonaccessible area exhaust filter plenum ventilation (VA) system ensures that radioactive materials leaking from the ECCS equipment within the pump rooms following a LOCA are filtered prior to reaching the environmerit.
Operation of the system and its effect on offsite dosage calculations were assumed in the safety analyses. The flow rate limit in Technical Specification 4.7.7 ensures that airborne contamination is minimized for ALARA and that area temperatures are maintained for Equipment Qualification.
The current Technical Specification surveillance requires nonaccessible area exhaust filter plenum flow to be 66,900 cfm i 10%, Original plant design calculations established a plenum design flow rate of 66,900 cfm based on calculated room heat loads. Air flow acceptance criteria of i 10% is the standard acceptance criteria from Westinghouse Standard Technical Specifications (NUREG-0452, Revision 4) and ANSI N510-1980.
RescriptioaandEases_ottbe.]equestedBevis. ion The proposed amendment changes the surveillance flow rate acceptance critena from 66,900 + 10% to between 55,669 cfm and 68,200 cfm.
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'. Byron Unit 2 startup test results for the VA system indicated that actual l
non accessible area exhaust system flow rates were less than originally calculated. The minimum acceptable air flow rate was recalculated based on revised calculated room heat loads and the air flow required to minimize airborne contamination. The revised system design flow rate was calculated to 1 be 62,730 cim. The calculated minimum acceptable system flow rate of 55,669
- cfm is the proposed Technical Specification surveillance lower bound. The proposed Technical Specification upper bound is 110% of the filter rated capacity of 62,000 cim. This is consistent with the acceptance critaria of ANSI N5101980. Based on these bounds, the proposed flow range is 88.7% to 108.7% of the revised system design flow.
Impact.otthe PJoposed_ Change The change does not affect the system's ability to perform its safety function.
The revised total system air flow rates for the VA nonaccessible area exhaust -
filter plenums ensure that radioactive materials leaking form the ECCS equiament l within the pump rooms following a LOCA are filtered prior to reac11ng the environment. The Standard i echnical S ecification for the ECCS pump room exhaust air cleanup systems and ANSI Nk10-1980 use an acceptance criteria of *10% of desigr> fie The slightly lower values proposed in this change are acceptable because the lower flow rates increase res dence time in the charcoal adsorbers, which
- 1mproves efficiency. Engineering calculations F-VA-430 and F-VA-431 show that the lower flow is acceptable. These two calculations are based on the total ventilation requirements and the sum of the individual room ventilation requirements, respectively. Therefore, the proposed change has no adverse
- impact on system performance or on the of: site dose calculations.
The proposed changes in VA system flow rates will not affect the differential pressere between the control room and adjacent areas. The absolute pressure in the auxiliary building is not significantly changed by the new flow range.
- 3. Eliminate Bank Flow Testing DescuptiortandEases of the CutrROLB9Qukemeut
' The proposed amendment eliminates the requirement for periodic bank flow testing and adds a requirement to perform bank flow testing after any structural maintenance or modification of the filter housing. This is consistent with the L guidelines in ANSI N510-1980. This is also consistent with the Standard y Technical Specification for ECCS pump room exhaust air cleanup systems (the -
L equivalent of Byron's nonaccessible area exhaust filter pienum ventilation system, or VA system). The correct flow distribution for the VA Nonaccessible alenums was achieved by installing permanently welded baffle plates during the o nitial construction.. There is no reason for the flow rates to change becauso L there are no variable dampers, and the baffle plates remain in a fixed position.
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The startup testing program verified that the flow distnbution was within the l acceptance criteria in tle ANSI guidelines. The flow distribution has been '
verified periodically in accordance with station procedures. The surveillance data verify.that the air flow distribution has remained uniform since the baffle plates were installed.-
The current Technical Specification 4.7.7.f requires the bank flows to be 22,000 cfm i 10% per bank. The proposed amendment adds a new survalliance, 4.7.7.g; to require bank flows to be between 18,566 and 22,733 cfm after <
structural maintenance changes. These flows were. calculated by dividing the total flow rate proposed in 4.7.7 by the number of banks. These flowrates
- ensure that the flow is evenly distributed, and that the total nonaccessible exhaust flows remain within their design requirements.
Eliminating the periodic testing requirement also enhances personnel safety.
The current bank flow rate testing requires that two test engineers work inside the plenums while the fans are in operation. The engineers must climb to different elevations within the plenum to gather the test data. After the data are collected, another person stationed outside, must assist the test er;gineers in
- opening the plenum door due to the differential pressure that develops during the test. Throughout the testing, the engineers are required to be in the exhaust stack air environment. The activities associated with this test method
- were identified as a safety concern.
- 1ImpacLQLtheffp20sedfhange Deleting the requ rement does not affect the operation or effectiveness of the VA exhaust filter plenum system. Eliminating the periodic bank flow testing -
. requirements does not affect any accident because the flow distribution through the plenums has been permanently set by the installation of baffle plates.
- 4. Edhorial Changes DeaC0 phoftand. Bases 1(the.QunienLBequirement Techn cal Specification 3.7.7 has a footnote stating that the requirement is not applicable prior to July 1,1985. A similar footnote in 4.7.7d.3 states that the requirement is not applicable to Unit 2 until October 1,1987. A' statement in
-4.7.7.b.2 refers to methyl "idodide".
DescriptionmiBases of.theJ3equested Revision The proposed amendment removes the two footnotes and associated asterisks because the referenced dates have passed and the footnotes are no longer required. The word:"idodide"is being corrected to " iodide".
ImpaolottbeftopoMMLChange Eliminating the footnotes and correcting the spelling of " iodide" are purely administrative changes and do not affect any accident analysis results.
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- 5. DOP Testing Description.anclBaserwLthtCurrentEequ.irement Technical Specification Surveillances 4.7.7 b.4 and 4.9.12.b.4 state that cold DOP (di 2-ethylhexyl phthalate) is used for testing the VA system.
Desctlption_and_ Bases o oltbeBequested Bevision The proposed change replaces " cold DOP" with "DOP" to provide a more accurate description of the VA System testing. ANSI N510-1980 allows either
" cold" or " hot" DOP for testing since both produce a polydisperse liquid aerosol with a droplet size distribution. No differentiation is needed and the deletion of the word " cold" allows testing consistent w!th the ANSI requirements without an unnecessary restriction to use cold DOP.
Impactoltbe_P_mposed_ Change There is no effect on any accident analyses because removal of the restriction to perform " cold" DOP testing is consistent with the ANSI ge!delines and the
- accident analyses results are unrelated to the specific test methodology employed.
ScheduleBeguifements' - -
Byron would like to imolement the changes prior to June 1993. The amendment supports a modificatio'n that wou'd replace charcoal delta pressure alarms with flow alarms to eliminate distraction alarms in the main control room. The proposed amendment affects the setpoints of the flow alarms.
In addition,'the nature of the bank flow testing is a personnel safety concern in that the pienum door cannot be opened by the engineers inside the plenum due to the differential pressure that develops during the test. Eliminating the bank flow testing limits the number of times that the test engineer must be inside the plenum in the exhaust stack air.- Provisions are made for testing following activities that may change the bank flow rates.
Identificati00_and.discussioILolaDyjfIDYemibklConSeque0ceS There would be no irreversible consequences as a result of the proposed changes.
It should be noted that UFSAR subsection 6.5.1.2.1.d.2 will be revised to reflect the new sizing criteria of the heaters.
Conclusion . -
Based upon the information presented above, it can be concluded that the proposed changes do not constitute an unreviewed safety question.
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