ML20078F061
| ML20078F061 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/27/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078F059 | List: |
| References | |
| NUDOCS 9502010294 | |
| Download: ML20078F061 (7) | |
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o WASHINGTON, D.C. EMBE SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 4
RELATED TO ANENDNENT No.167 TO FACILITY OPERATING LICENSE N0. DPR-46 NEBRASKA PUBLIC POWER DISTRICT COOPER NUCLEAR STATION
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DOCKET N0. 50-298
1.0 INTRODUCTION
In a letter dated July 26, 1994, Nebraska Public Power District submitted an amendment request for the Cooper Nuclear Station. This request involved a design change to the control room emergency filter system and a revision to Technical Specifications (TS) 3/4.12.A. The proposed design change would increase the pressurization flow of the control room emergency filter system from 341 cubic feet per minute (cfs) to 1,000 cfm. The change was proposed as
-an interim resolution to the continuous problem Cooper has experienced with respect to maintaining the control room envelope at a positive pressure with respect to all adjacent areas.
The proposed design change necessitates a revision to the existing control room emergency filter system TS.
In the July 26,1994, submittal the licensee proposed the following changes:
1.
In Limiting Condition for Operation (LCO) 3.12.A.1, the term
" containment" would be clarified to indicate " primary or secondary".
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Existing LCOs 3.12.A.2.a and 3.12.A.2.b would become Surveillance Requirements (SRs) 4.12.A.2.c and 4.12.A.2.d, respectively.
In addition, the flow rate of 341 cfm specified in LCO 3.12.A.2.c i
would be deleted and it would be specified that the DOP and i
halogenated hydrocarbon tests would be performed at the system design flowrate.
In LCO 3.12.A.2.d, the inlet condition for the velocity in the laboratory test of charcoal would be changed from i
22 fpm to 39 fpm to account for the addition of the third tray of 3
charcoal to the enntrol room emergency filter system.
3.
LCO 3.12.A.2.c would become the last sentence in LC0 3.12.A.I.
However, it would be altered to indicate that the flow rate for the emergency bypass fan should now be < 1,000 cfm.
Previously, 3
it had been 341 +/- 10%.
In addition, the verb "shown" would be replaced with the verb " demonstrated."
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9502010294 950127 PDR ADOCK 05000298 P
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As a result of the deletion of LC0 3.12.A.2, LCOs 3.12.A.3 and i
3.12.A.4 would be renumbered.
5.
All of the existing SRs of 4.12.A would be renumbered.
6.
The reference to LC0 3.12.A.2 would be changed to refer to SRs 4.12.A.I.: and 4.12.A.I.d.
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A new SR, 4.12.A.I.i would be added to state that at least once per operating cycle, demonstrate that the control ruos emergency filter system can maintain positive pressure relative se adjacent areas at a flowrate of < 1,000 cfm.
In a letter dated December 27,.1994, the licensee proposed a revision to their July 26, 1994 submittal. The changes proposed were intended to address the lack of specificity for the system flowrate. The licensee proposed to delete the last sentence of LC0 3.12.A.2, which read, "The emergency bypass fan shall be demonstrated to provide < 1000 cfm." In addition, the term " system design flowrate" was replaced in SRs 4.12.A.I.a and 4.12.A.I.c to indicate "at a flowrate of 900 cfm i 10%." The maximum flowrate specified in SR 4.12.A.I.i was revised from "< 1000 cfm" to "s 990 cfe" to correspond to the 900 cfm i 10%.
To support the increase in the quantity of pressurization flow, the licensee performed calculations to demonstrate that the increase in pressurization flow would not result in the control room operator doses exceeding 10 CFR Part 50 Appendix A General Design Criteria (GDC) 19. The whole body and thyroid doses l
were calculated. These calculations, which were part of the July 26, 1994, submittal were revised by the licensee as presented to the staff on January 19, 1995.
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2.0 BACKGROUND
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On April 18, 1994, the Cooper Nuclear Station received from the staff a Notice of Enforcement Discretion from the Cooper TS LCO 3.12.A.3 due to the j
licensee's inability to establish the control room envelope at a positive pressure with respect to all adjacent areas. The design of the control room
-i emergency filter system at Cooper is to draw outside air at 341 cfm and to pass it through a HEPA filter and a charcoal adsorber to remove radioiodine and particulates.
It was intended that the 341 cfm would be sufficient to maintain the control room envelope at a positive pressure relative to all adjacent areas, thereby limiting the quantity of unfiltered inleakage into the i
envelope. The degree to which the envelope must be maintained positive has l
been an issue between the staff and the licensee.
In the licensee's s
December 30, 1980, response to TMI Action Item III.D.3.4, the licensee provided information which indicated that the control room envelope was I
designed to maintain a positive pressure of 1/4 inch w.g. relative to all i
adjacent areas.
In an October 14, 1987, letter to the staff the licensee stated that the design basis for the control room envelope re, quired a minimum positive pressure of 0.1 inch w.g.
In Bases Section 3.12 of the TSs, it is stated that the control room envelope only needs to be maintained at a positive pressure with respect to all adjacent areas.
i Because of problems associated with the pressurization of the control room I
during the first six months of 1994, the licensee met with the staff on July 7, IM4. At that meeting, the staff and the licensee agreed to an interim resolution to the control room envelope pressurization value.
It was agreed that at control room envelope pressures less than 0.03 inches w.g., the envelope would be considered ihoperable, (i.e., incapable of performing its intended function). At control room differential pressures (Ap) <0.04 inches w.g., but 20.03 w.g., additional surveillance testing to demonstrate the control room pressurization capability would be required.
Although the licensee concluded t' the integrity of the control room envelope was such that a pressu-ation flowrate of 341 cfm would produce a
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control room envelope 4 of 0.C. inches w.g., they indicated that it was their I
intent to achieve an increase in the positive pressure margin, both in the i
l interim and long term. The licensee investigated various solutions to improve the capability of the control room to obtain a significant positive 3ressure.
While a final solution has not been determined, an interim solution tas.
Tu pressuritation flow of the control room emergency filter system will be increased to 1,000 cfm. This increase will require replacement of the existing control room emergency filter system fan and the addition of a third tray to the charcoal in the control room emergency filter system. Currently the charcoal only has the capability to handle 666 cfm. With the addition of the third tray, the control room emergency filter system will have sufficient capacity to treat the new pressurization flowrate of 1,000 cfm.
The licensee's July 26, 1994, letter indicated that with the design change to 1,000 cfm, the operability and administrative limits for control room op would become 0.04 inches w.g. and 0.05 inches w.g., respectively. This was an increase from the operability and administrative values of 0.03 a.d 0.04 which the staff had previously agreed. As aroposed by the licensee, when the control room envelope op is 20.05 incies w.g., the surveillance testing for pressurization would be performed monthly.
If the op was in the range of 0.04
< op < 0.05 inches w.g., an accelerated testing frequency would be instituted to ensure that the limit of 0.04 was met. Testing frequency would be once every two weeks. Two successive biweekly tests with the pressure 20.05 inches w.g. would allow the licensee to return to the monthly test frequency.
The licensee has indicated that the long term solution may require additional modifications and that they are evaluating the final fix to this problea. The 1
licensee has committed to making any additional modifications during the next refueling outage and to submitting any additional changes to the TSs including a fixation of the value for op.
3.0 EVALUATION 1
The staff reviewed the licensee's submittal of July 26, 1994. As a result of this review, a conference call was held between the licensee and the staff on December 20, 1994, to discuss the proposed TS changes r.nd the dose calculation
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assumptions. On December 27, 1994, the licensee revised their original TS amendment request submittal. On January 19, 1C95, the licensee presented a j
revised dose ass 9ssment which incorporated assumptions different than those I
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i previously contained in their analysis to support the TS change proposed.in their July 26, 1994 letter. The licensee's assessment of the control room operator doses indicated that the limiting accident was the loss-of-coolant i
-accident (LOCA), but an analysis had also been performed for a fuel handling accident.
The NRC staff has independently calculated the control room operator doses for the LOCA.and two other postulated accidents, the main steamline break and a i
control rod drop. The staff performed such an evaluation to determine if the increase in makeup filtration flow and in unfiltered inleakage would alter their previous conclusion that the control room operator doses were within the i
limits of GDC 19.
The staff conc 1cded that, while the licensee's design change to increase pressurization flow improved the iodine protection factor for the control room operator, the requirements of GDC 19 could not be met without some compensatory actions. Therefore, in a letter dated January 27, 1995, to the staff, the licensee committed to ensuring the availability of 1
potassium io< tide (KI) thyroid-blocking tablets to the Cooper control room l
operators in the event of an accident involving core damage. With this i
compensatory action, the staff has concluded that the requirements of GDC 19 i
will be met.
Therefore, the change in the control room emergency filter l
system design to increase pressurization flow is acceptable to the staff.
In addition, the staff finds that the proposed changes to the TSs for the control i
room emergency filter system are appropriate, k
However, it should be noted that the use of the compensatory action is only for an interim period. The staff expects a proposed resolution to the use of l
the compensatory action and to the question of the appropriate op relative to all adjacent areas to be forthcoming from the licensee by the next refueling i
outage.
4.0 EMERGENCY CIRCUMSTANCES The Commission's re ulations in 10 CFR 50.91 contain provisions for issuance of amendments with ess than a 30-day comment period if emergency circumstances are determined to exist.
Emergency situations involve those cases in which failure to act in a timely i
way results in the derating or shutdown of a nuclear power plant or prevents either resumption of operation or increase in power outsut up to the plant's licensed power level. Under emergency circumstances, tie Commission may issue a license amendment involving no significant hazards consideration without prior notice and opportunity for a hearing or for public comment.
In such a situation, the Commission publishes a notice of issuance under 10 CFR 2.106, providing for opportunity for a hearing and for public comment after issuance.
For emergency circumstances, the licensee is required to explain the reason for the condition and why it could not be avoided. This requirement is intended to prevent the abuse of the special provisions of 10 CFR 50.91(a)(6).
The Commission has previously issued a proposed finding that the amendment, based on the licensee's July 26, 1994, application involves no significant
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hazards consideration and there has been no public coment on such finding (59 FR 45026. On January 19, 1995, at the request of the NRC staff, the licensee pres)ented a revised dose assessment which incorporated assumption f.
different than those previously contained in their analysis to support the TS l
change proposed in their July 26, 1994 application. Based on the NRC staff review of the dose assessment, and during a series of teleconferrences held i
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with the licensee during the period January 20-25, 1995. it was detemined i
i that the licensee and tie NRC staff were in disagreement over various assumptions used in the licensee's dose calculation. The NRC staff's evaluation indicated that additional protective measures are needed to ensure that GDC 19 criteria are met.
The licensee's January 27, 1995, letter supplementing the July 26, 1994, application committed to an interim measure that was determined to be necessary based on disparities between the licensee and the NRC staff's evaluations of the control room operator dose consequences for a LOCA whie results in core damage. Although the contents of this supplement do not l
affect the conclusions previously reached by the staff's significant hazards l
l analysis, the licensee's commitment to the stated interim measure represents j
changes to the intent of the July 26, 1994, application.
The licensee requested that the NRC staff consider the January 27, 1995, submittal as an emergency request for approval of the original TS amendment application, to support the performance of the reactor vessel hydrotest on January 29, 1995, which is required prior to startup from the current outage.
Failure to grant this amendment promptly could result in preventing restart of the plant.
Based upon the above considerations, the staff concludes that there are emergency circumstances present that warrant issuance of the amendment pursuant to 10 CFR 50.91(a)(5).
5.0 NO SIGNIFICANT HAZARDS CONSIDERATION The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards consideration if the operation of the facility in accordance with the amendment would not:
(1)
Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2)
Create the possibility for a new or different kind of accident from any accident previously evaluated; or (3)
Involve a significant reduction in the margin of safety.
The Commission has pteviously issued a proposed finding that the amendment, based on the licensee's July 26, 1994, application involves no significant hazards consideration and there has been no public comment on such finding (59 FR 45026). The licensee's proposed changes to the July 26, 1994,
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' application dated December 27.-1994, do not change the intent of the application nor affect the conclusions reached by the significant hazards analysis. These changes simply clarify a reasonable value for the system design flowrate, and ensure through Technical Specification controls that the surveillance tests will reflect actual perfomance capability for the control room emergency filter system.
The licensee's January 27, 1995, letter supplementing the July 26, 1994,
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application committs to an interim measure that was detemined to be necessary based on disparities between the licensee and the NRC staff's evaluations of the control room operator dose consequences for a LOCA which results in core l
damage. This interin measure (providing operators with KI for use as blocking l
agent) forms part of the basis for the staff's conclusion that the licensee j
will comply with the criteria of 10 CFR Part 50 Appendix A, GDC 19. Because this interim measure will not affect plant hardware or operations, and will only be implemented as a compensatory action to mitigate dose consequences to i
operators in the very unlikely event of a LOCA with core damage, the staff concludes that the additional interim measure committed to in the January 27, 1995, letter also does not:
(1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (dent 2) create the possibility for a new or different kind of accident from any acci l
previously evaluated; or (3) involve a significant reduction in the margin of i
safety.
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Based upon the above considerations, the staff concludes that the &mendment
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meets the criteria of 10 CFR 50.92. Therefore, the staff has made a final determination that the proposed amendment does not involve significant hazards l
considerations.
6.0 STATE CONSULTATION
i In accordance with the Commission's regulations, the Nebraska State official was notified of the proposed issuance of the amendment. The State official had no comment.
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7.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to increased flow capacity of i
the control room emergency filter system. The NRC staff has determined that j
the amendment involves no significant increase in the amounts, and no signi-l ficant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has made a final no significant hazards consideration determination with respect to this amendment. !ccordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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8.0 CONCLUSION
The Commission 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J. Hayes l
Date: January 27, 1995 f
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