ML20196E303
| ML20196E303 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 12/05/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20196E299 | List: |
| References | |
| NUDOCS 8812090311 | |
| Download: ML20196E303 (6) | |
Text
/[
UNITED STATES y*
g NUCLEAR REGULATORY COMMISSION t.
.j WASMNGTON, D. C. 20555
%,..../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.22 TO FACILITY OPERATING LICENSE NO. NPF-42 KANSAS GAS & ELECTRIC COMPANY KANSAS CITY POWER AND LIGHT COMPANY KANSAS ELECTRIC POWER COOPERATIVE. INC.
WOLF C_ REEK GENERATING STATION DOCKET NO. 50-482
1.0 INTRODUCTION
By letter dated February 26, 1988 and supplemented on October 31, 1988, Wolf Creek Nuclear Operating Corporation (WCNOC), the licensee for Wolf Creek Generating Station Unit No. 1, provided a proposed revision to Technical Specifications (TS) 3/4.7.6, Control Room Emergency Yentilation System, 3/4.7.7, Emergency Exhaust System (Plant Systems), 3/4.9.1J Emergency Exhaust System Systems) g Operations), TS Bases B 3/4.7.7, Emergency Exhaust System (Plant (Rafuelin and B 3/4.9.13, Emergency Exhaust System (Refueling Operations).
The purposes of the proposed changes are to provide an optimum pressure balance between the control building and the auxiliary building and to provide for dirty filter differential pressures (dps) censistent with the system flow rate needed to achieve the optimum balance; identify the unique surveillance requiremants relevant to the use of the er.ergency exhaust system for minimizing radiatien releases following a loss-of-coolant accident (LC;A) versus follcwing a fuel handling accident in the fuel building; delete unnecessary and redundant surveillance requirements; and clarify the Bases accordingly.
The licensee identified the proposed changes as follows:
a.
The changes in TS 3/4.7.6 consist of: 1)increasingthecontrolroom prnsurization system flow rate from 500 cfm 10% to 750 cfm 210% in all applicable portions of 4.7.6; 2) chang (ing the pressurization system dirty filter dp from 3.8 inches Water Gauge W.G.) to 3.6 inches W.G. in all applicable portions of 4.7.6; 3) deleting the dirty filter dp requirements in 4.7.6.c.1; 4) adding a maximum allowable dp for the pressurization system filter unit in 4.7.6.e.1; 5) deleting the 0.05% in-place penetratien and bypass leakage testing for charcoal filters in 4.7.6.f which tests high-efficiency particulate air (HEPA) filter irtegrity; and 6) deleting the 1% in-place penetration and bypass leakage t sting for HEPA filters in 4.7.6.g which tests charcoal filter integrity, b.
The changes in TS 3/4.7.7 consist of: 1) adding "Auxiliary Building" in the identification title; 2) deleting all sections of 4.7.7 dealing with testing of the adsorber unit and fan flew rates and replacing with requirements to G312090311 881205 PDR ADOCK OS0004A2 P
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perform the same adsorber testing at the appropriate flow rates per 4.9.13;
- 3) in renumbered paragraph 4.7.7.b.1 changing "Fuel" to "Auxiliary" to correctly identify the appropriate building; and 4) renumbering as necessary due to deleted / transferred testing requirements.
c.
The changes in TS 3/4.9.13 consist of: 1) adding "Fuel Building" in the identification title; 2) reducing the required fan flow rate from 9000 cfm 110% to 6500 cfm 110% for all applicable sections of 4.9.13; 3) changing the dirty filter dp from 7.2-inches W.G. to 4.7-inches W.b. in all applicable sections of 4.9.13; 4) deleting dirty filter requirement in 4.9.13.b.1;
- 5) transferring 4.9.13.d.2 and 4.9.13.d.3 to new section 4.9.13.g as e.9.13.g.1 and 4.9.13.g.2 and renumbering 4.9.13.d as applicable; 6) leleting 0.05% in-place penetration and bypass leakage testing from charcoal adsorbert in 4.9.13.e; anc' 7) deleting the 1% in-place penetration and bypass leakage testing from HEPA filters in 4.9.13.f.
d.
The changes in the Bases consist of: 1) changes in the identification titles for 3/4.7.7 and 3/4.9.13; 2) changing "pump room" to "Auxiliary Building" in 3/4.7.7; and 3) adding that the surveillance requirements associated with the filtration unit for 3/4.7.7 are stated in TS 4.9.13.
No change is proposed to the TS surveillance requirements that the control room emergency ventilat*on system maintain the control room at a positive pressure of greater than or equal to 1-inch W.G. relative to the outside atmosphere or that the emergency exhaust system maintain the auxiliary building and the fuel building at a negative pressure of greater to or equal to 1-inch W.G. relative to the outside atmosphere.
2.0 BACKGROUND
The three Technical Specifications for which the licensee has requested the changes address the three safety-related ventilation systems associated with maintaining control room habitability and minimizing radioactivity releases to 1
the environment for postulated accidents involving irradiated fuel.
The licensee has pavided the following background information on the proposed changes:
TS 3/4.7.6 ensures a positive pressure envelope of filtered air to the control room to ensure habitable conditions in the control room under accident conditions.
The positive pressure envelope is created by the pressurization system discharging outside filtered air into the portions of the control building that provide the suction for the contiol room filtration system, which provides continual filtering of control room air.
TS 3/4.7.7 ensures that radioactive materials leaking from eme gency core cooling system (ECCS) pumps in the auxiliary building during LOCA conditions
are not allowed to :nigrate to the outside atmosphere without being filtered.
This is accomplished by creation of a negative pressure in the auxiliary building of greater than i-inch W.G. during safety injection actuation as the emergency exhaust system is aligned to take a suction on the auxiliary building.
The emergency exhaust system filters the air before discharging to the environment.
TS 3/4.9.13 ensures that radioactive material released from irradiated fuel assemblies will be filtered prior to release to the environment by creation of t
a negative pressure in the fuel building of greater than i-iach W.G. when the suction of the emergency exhaust system is aligned to the fuel building. The air is filtered through HEPA filters and charcoal beds prior to discharge to t5e environment. The filtration units and fan units identified as the emergency exhaust system in TS 3/4.7.7 and 3/4.9.13 are the same. Suc', ion isolation dampers within the system are aligned to either the duxiliary building or the fuel building as required by the specified initiating signal (Safety Injection or Fuel Building Isolation Signal).
With the present emergency exhaust flow of 9000 cfm 210% and the emergency exhaust system aligned to the auxiliary building, a negative pressure of approxi-mately 3-inches W.G. is created. This high negative pressure in the auxiliar, building reduces the positive pressure envelope in the control building to less than optimum levels due to leakage from the control building and control building filtration units into the auxiliary building. Reduction of emergency exhaust i
flow to 6500 cfm 10% and increasing the pressurization system flow from 500 cfm 210% to 750 cfm 210% provides adequate nagative pressure in the auxiliary butiding to ensure inleakage from the environment and establishes a more desirable positive pressure envelope within the control building.
Part of the function of the control room emergency ventilation system is to isolate the control building and provide a filtered supply of fresh air to the control room in the event of a Jesign basis accident (DBA). The safety-related i
filter units that are part of the control building heating, ventilation and air conditioning (HVAC) system are the control room filtration system filter adsorber units and the control room pressurization system filter adsorber i
units.
The control room flitration system filter adsorber units each consist of moderate efficiency prefilters HEPA filters, and charcoal adsorption beds.
Each control room pressurization system filter adsorber unit is comprised of a demister, electric heater, HEPA filters, and charcoal adsorption beds. A complete description of the system is provided in Section 9.4.1 of the Standardized Nuclear Unit Power Plant System (SNUPPS) Final Safety Analysis Report (FSAR).
The control room pressurization system will maintain a 1/4-inch W.G. positive pressure in the control room to ensure exfiltration and prevent excess quantities of unprocessed contaminants from entering the control room.
The operability of this system is based on Ifmiting the radiation exposure to personnel occupying the control room to 5 rems or less whule body, or its equivalent, which is i
consistent with general design crite.*ia (GDC) 19 of Appendix A to 10 CFR Part 50.
The emergency exhaust system is on standby for automatic startup af ter an initiation l
signal indicating fuel building isolation or a LOCA condition for the auxiliary l
l
building. The system maintains a 1-inch W.G. negative pressure in the fuel building to ensure that all leakage is into the building. The emergency exhaust system filter /adsorber units are located in the fuel building, and each filter train consists of moderate efficiency prefilters, HEPA filters, and charcoal adsorption beds.
The emergency exhaust system would operate after a LOCA to limit and reduce fission product releases from the auxiliary building.
The system would also operate after a fuel-handling accident to control and remove fission product releases from the fuel buildig. This system operates to ensure that the off-site radiation exposures after the above mentioned accider.ts are within the guidelines of 10 CFR Part 100.
3.0 EVALUATION The licensee stated the following in support of the proposed changes:
a.
The new flow rate for the pressurization system (TS 3/4.7.6) was evaluated to ensure: 1) compliance with Regulatory Guides 1.78 and 1.95 which limit chlorine concentration in the control room to 15 ppm or less during any postulated chlorine release and 2) compliance with Criterion 19 of Appendix A to 10 CFR Part 50, which limits control room personnel radiation exposure to less than 5 rem whole body for the duration of postulated accidents.
b.
The system flow rates at a given pressure drop are verified under TS 3/4.7.6.c.3 and 3/4.9.13.b.3, where the dirty filter dp was reduced to ensure that the flow rates stay within the specified range as the dp increases from the clean filter dp to the maximum allowable dirty filter dp.
The proposed changes concerning the deletion of dp verification across the filters for the filtration system and pressurization system under TS 3/4.7.6.c.1 and deletion of the dirty filter dp verification under TS 3/4.9.13.b.1 are in accordance with the current revision of the Westinghouse Technical Specifications (NUREG-0452) and meet the requirements of Generic Letter 83-13. "Clarification of Surveillance Requirements for HEPA Filters and Charcoal Adsorber Units in Standard Technical Specifications on ESF Cleanup Systems."
c.
The emergency exhaust system for the fuel buildirg and auxiliary building is served by the same fans ((dG02A and CGG028). Since a flow reduction from 9000 cfm 2 10% to 6500 cfm 10% is required for the auxiliary building, the same change must be made for the fuel building flow rates.
d.
The negative pressure level limits in the auxiliary building and fuel building are not affected by the proposed TS changes. The negative pressure requirements of i-inch W.G. ensures that exfiltration from the buildings does not occur. During accident conditions effluents from these buildings are processed through safety-telated filter /adsorber units prior to release via the unit vent.
The actual performed field testing in the
n.
.S.
fuel building and auxiliary building at the new rated flow of 6500 10%
ensures that an adequate margin of negative pressure in excess of 1-inch W.G. could be maintained.
(A nep tive pressure range of 0.3 inch W.G. to 0.5 inch W.G. was achieved during testing in both buildings),
e.
Wolf Creek Generating Station continues to ccmply with Position 31 of Reguidory Guide (R.G.) 1.52.
For the emergency exhaust system the proposed reduction in flow will result in an increase in the "residence time" of effluent in the charcoal bed (0.25 sec/2 inch minimum). Also, the control room pressurization system was designed to meet the Regulatory Guide (R.G.) 1.52 minimum residence time at a flow rate of 1000 cfm, which bounds the proposed increase in pressurization' flow from 500 cfm to 750 cfm.
f.
The other requested changes to TS 3/4.7.6, 3/4.7.7 and 3/4.9.13 serve to clarify wording, delete unnecessary wording, and tu clearly identify the required testing on the emergency exhaust system filtration unit. Current.ly, redundant identical testing requirements are contained under Surveillance Requirements 4.7.7 and 4.9.13 for the filters. The change eliminates confusion, and no testing requirements are deleted by any of the proposed changes.
The staff has reviewed the above changes and supporting rationale and concludes that 1) the resulting value ::f the iodine protection factor (IPF), for use in the radiological dose calculations for control room personnel, is not decreesed with the proposed flow changts in comparison to the IPF without these changes (The methodology and other assumptions in the calculation would otherwise be unchanged); and 2) the accident releases will be adequately controlled as before during the postulated accident conditions in the auxiliary buildino end fuel building since the negative pressure level limits and the iodine rsmoval efficicncy of the filters are not affected by the reduction in emergency exhaust system flow from 9000 cfm 10% to 6500 cfm i 10%.
In addition, the staff concludes that (1) the proposed Wolf Creek control room habitability system operation with the revised ventilation and exhaust air flow rates still meets the requirements specified in GDC 19 and standard review plan (SRP)
Section 6.4 for the protection of control room personnel under accident conditions and (2) the proposed Wolf Creek TS changes do not alter our conclusion provided in the Wolf Creek SER Section 6.4 Based on this, after a LOCA or a fuel-handling accident, offsite radiation exposures and radiation exposures to personnel occtpying the control room will not be increased due to the proposed changes.
In addition, other charges provide appropriate clarifications and/or deletion of unnecessary descriptions and are consistent with the Standard Technical Specifications.
Based on the above evaluation, the staff finds the proposed changes to the TS and Bases for the cotstrol room emergency ventilation system and emergency exhaust systems for thr eux111ary building and fuel building to be acceptable.
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4.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32 and 51.35, an environmental assessment and finding of no si nificant im act was published in the Federal Register on December 5. 1988 53 FR 48991.
Accordingly, based upon the environmental assessment, the Commission has determined that issuance of this amendment will not have e significant effect on the quality of the human environment.
5.0 CONCLUSION
2 A Notice of Consideration of Issuance of,*,mendrent to Facility Operating License and Opportunity for Hearing was published in the Federal Register on August 26, 1988 (52 FR 32804).
No requests for licensing or petitions /or leave to intervene was received.
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, i
and the issuance of the amendrent will not be inimical to the common defense and security or to the health and safety of the public.
Dated: December 5,1988
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Principal Contributors:
C. Nichols J. Raval J. Lee I
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