ML20043E720
| ML20043E720 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/07/1990 |
| From: | Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Withers B WOLF CREEK NUCLEAR OPERATING CORP. |
| References | |
| NUDOCS 9006130317 | |
| Download: ML20043E720 (8) | |
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In~ Reply Refer To:
Docket: STN 50-482 Wolf Ereek Nuclear Operating Corporation ATTNi
' art D. Withers
' resident and Chief Executive Officer P.O. Box 411 Burlington, Kansas 66839 Gentlemen:
This is in response to your May 19, 1989, letter in reply to the NRC backfit questionnaire and letter dated April 7,1989, from E.
L._ Jordan to all licensees of operating reactors.
In your May 19, 1989, response to the questionnaire, the Wolf Creek Nuclear Operating Corporation (WCNOC),
identified several potential backfit items or items wherein the NRC staff practice was inconsistent with the guidance of Manual Chapter 0514.
The specific issues identified were:
a) vital area access, b) security compensatory measures, c) system operability related to ASME code requirements, and d) emergency action levels (EALs).
The Region IV backfit review panel critiqued these matters. As discussed with you previously, no backfits were confirmed for vital. area access, security compensatory measures, and system operability related to ASME code requirements. However, a backfit was confirmed for the issues involving EALs.
Therefore, the Region IV staff requested a regulatory analysis on the EALs issue and the Emergency Preparedness Branch of the Office of Nuclear Reactor Regulation performed the resulting regulatory analysis in the enclosure to this letter.
1 The enclosed regulatory analysis, performed in accordance with the guidance of
-10 CFR 50.109 and NRC Manual Chapter 0514, concluded that there was indeed a l
backfit on the issue of EALs and that such backfit provided a substantial increase in the overall protection of the public health and safety.
The regulatory analysis confirmed the inadequacy of your original barrier scheme
'that required the breach or serious challenge of one or more fission product barriers in order to reach an Alert or' higher emergency classification.
As a result of the above considerations, NRC has decided to permanently
Under NRC Manual Chapter 0514, you have the right to appeal-our decision, and request us to change or withdraw the EAL backfit.
To
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-Wolf. Creek Nuclear Operating Corporation: !
do so,-you.must provide arguments against the rationale for imposing the backfit as presented in the staff's regulatory analysis. Address the appeal to the Regional. Administrator, Region IV, with a copy to the Executive-
' Director for Operations.
' ORIGINAL GIGNED BY:.
Robert D. Martin 1'
Regional Administrator t
Enclosure:
As stated-cc-w/ enclosure:
Wolf Creek Nuclear Operating Corp.
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-ATTN: Gary Boyer, Plant Manager P.O. Box'411' i
Burlington, Kansas 66839
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Shaw, Pittman, Potts & Trowbridge
'c ATTN: -Jay Silberg, Esq.
1800 M Street, NW Washington, D.C.
20036 Public Service Commission
~ ATTN: :Chris R.- Rogers, P.E.
Manager, Electric Department O
P.O. Box 360 f
Jefferson City, Missouri 65102 U.S. Nuclear Regulatory Commission ATTN:
Regional Administrator, Region III
~ 799 Roosevelt Road Glen Ellyn, Illinois 60137 Wolf Creek Nuclear Operating Corp.
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-ATTN:
Otto Maynard, Manager Regulatory Services e
P.O. Box 411 Burlington, Kansas 66839 7
Kansas Corporation Commission p
ATTN:
Robert Elliot, Chief Engineer
- Utilities Division 4th Floor - State Office Building Topeka, Kansas 66612-1571 y
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' Wolf Creek Nuclear Operating Corporation,
-i Office of the Governor
'i State of Kansas Topeka, Kansas 66612 Attorney General i;
L Ist Floor - The Statehouse
. Topeka,' Kansas l 66612 2 Chairman,-Coffey County Commission Coffey County Courthouse
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Burlington, Kansas 66839 Kansas' Department'of Health
.and Environment Bureau of Air Quality &' Radiation
. Control
. ATTN:. Gerald Allen, Public
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Health Physicist Division of Environment t-T Forbes Field _ Building 321 Topeka, Kansas-66620 U.S. Nuclear Regulatory Commission J
ATTNi Senior Resident Inspector k
P.O. Box 311-Burlington, Kansas 66839 w
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lU.S.NuclearRegulatoryCommission
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Regional Administrator, Region IV 611LRyan Plaza Drive, Suite 1000 n
Arlington, Texas 76011 a
i Program' Manager FEMA'. Region 7 s
911 Walnut Street, Room 200 i
Kansas City, Missouri '64106 i
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Regulatory Analysis (Manual Chapter 0514)
Wolf. Creek Emergency Action Level Backfit a.
A Statement of the specific objective that the proposed backfit is designed to achieve. This should also include a succinct description of-the backfit proposed, and how it provides a substantial increase in overall protection.
The Wolf Creek Generating Station (WCGS) emergency action level (EAL) classitication procedure prior to 1988 was a " pure" fission product barrier i
scheme. -This seneme required the breach or serious challenge of one or more
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fission procact barriers (fuel clad, reactor coolant system, and containment) in order.to get to an Alert or higher emergency classification. Under this scheme, breach of one fission product barrier is an Alert, two barriers a Site i
Area Emergency and tnree barriers a General Emergency. However, in the absence-
. of fuel or reactor coolant system (RCS) barrier f ailure, a tailure of containmentisaNotificationofUnusualEvent(NOVE).
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.The " events" in the so-called event based emergency classification scheme in NUREG-0654 (loss of off site power, station blackout, fire, natural phenomenon and security. threat) would initially be classified as a NOUE under the WCGS seneme.
Subsequently, a mechanistic f ailure of the fission product barrier would have to be observable by the plant emergency director, or a higher clas-sification would not be declared, i.e., the plant would remain in a NOVE status.
Under the WCGS scheme,.the higher classifications of Alert and above would-also be delayed well beyond NUREG-0654' standards. Once an initial classification
.is made, for example, at a NOUE or an Alert, a prediction is required to be made of the-time to f ailure of the next fission product barrier. The higher emergency classification corresponding to breach of that barrier is not declared unless the interval elaspses without mitigation of the event. This is directly contradictory to the anticipatory nature of the guidance in NUREG-0654.
The WCGS plan itself describes this process as follows:
" Utilizing the WCGS Emergency Classification System (ECS), the DED is made a
aware of botn the current status of fission product barriers (intact /not intact) ano also probable mechanisms for subsequent unavoidable failures of acditional fission product barriers. The TSC staff, having determined probable and unavoidable mechanisms leading to the subsequent barrier failure, can also estimate the time to failure. Once the DED has been appriseo of a probable, credible, subsequent barrier f ailure and the estimated time to failure, he may consult the evacuation time estimates to determine the amount of time estimated to be required to complete a precautionary evacuation of the general public within the plume exposure emergency planning zone.
For those events in which conditions degrade rapidly, such that a significant release would mechanistically occur within the interval to implement evacuation, a reclassification of the event will be performed upon recognition of the degradation."
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Thus for a station blackout scenario, a General Emergency would be declared when the estimated evacuation time exceeded the estimated time to failure of l
tne thiro fission product barrier.
In contrast,.NUREG-0654 event based schemes would require declaration of an Alert at the initiation of station blackout, a Site Area Emergency after 15 minutes and a General Emergency after a total-loss of emergency f eedwater makeup' capability. for several hours.
, Protective action decision-making under the WCGS scheme depends upon the accuracy of the estimates of the time-to-f ailure of the third barrier and upon the accuracy of the estimates of evacuation times. Protective action decision-3 making under NUREG-0654 depends only on the severity of the event; for
.l example, fires or earthquakes substantially beyond the design basis which could cause massive common damage to plant systems woulo result in an immediate declaration of a General Emergency. Thus, under NUREG-0654 guidance tne declaration of a General Emergency would occur earlier and, nence, more conservatively from an emergency response standpoint, than under
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the WCGS scheme. This was graphically demonstrateo curing an emergency prepareoness exercise describec under item (f) below.
Af ter the backtit, the new WCGS EAL classification procedure became a hybrio scheme wherein the " events" in NUREG-0654 were added to the old WCGS fission product barrier scheme. Use of the new EAL classification scheme would result in an earlier classification at a higher level, hence alerting offsite authorities and the public earlier than the old pre-backfit scheme. This earlier classification and earlier alerting (especially for severe core damage events) of the offsite agencies and the public was, in fact, the specific objective of the backfit, as well as a reduction in reliance on estimates of the time-to-f ailure for plant systems (e.g., containment) and evacuation times, b.
A general description of the activity that would be required by the licensee in order to complete the backfit.
- The licensee nad reviseo its emergency plan and implementing procedures to include those events described in NUREG-0654 (loss of offsite power, station blackout,-fire, natual phenomenon and security threats) from NOUE through the higher emergency classifications. The licensee also had to train its operators on the new EAL scheme and provide guidance to State and local governments on the new EAL scheme.
c.
The potential safety impact of changes in plant design or operational complexity, including the relationship to proposeo and existing regulatory requirements.
The new EAL scheme was a modest change to the old scheme and brought the WCGS EAL seneme closer to existing guidance in NUREG-0654 and the philosophy of the NRC as expresseo in NUREG-1210.
d.
Whether the proposed backfit is interim or final and, it interim, the justification for imposit.g the proposed backfit on an interim basis.
The backfit was final. '
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A statement that describes the benefits to be achieved and the cost to be incurred.- _ Intormation should be used to the extent that it is reasonably
-available, and a qualitative assessment of benefits may be made in lieu of. the quantitative analysis where it would provide more meaningful insights, or is the only analysis practicable. This statement should include consideration of at least the following factors:
_j (1) The potential change in risk to the public f rom the accidental offsite release of radioactive material.
(2) The potential impact on radiological exposure of facility l
employees. Also consider the effects on other onsite workers,'due botn to installation of procedural or hardware changes and to the ef f ects of the changes, for the remaining lifetime of the plant.
(3) Tne installation ano continuing costs associated with the backfit, l
including the cost of f acility downtime or the cost of constuction delay.
u (4) The estimated resource buroen on the NRC associated with the proposed backfit and the availability of sucn resources.
The cost of amending tDe WCGS EAL scheme in the emergency plan and procedures
-ano the cost of trainir,g and other implementation measures is estimated to be less than 550,000. The'e are no incremental ongoing costs associated with this
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change tnat could be setarated f rom the ongoing costs of the emergency l
preparedness program. T,te resource burden on NRC was about $10,000 but this served to close out open items f rom the pre-licensing inspection and subsequent i
emergency preparedness exercise inspections.
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The' benefit to the public would only be realized-if WCGS experiences a. severe accident wherein their old EAL scheme might not have notified the public in as timely a fasnion as the new EAL scheme.
For example, during an actual station l
blackout under the old scheme, the site would be under a NOUE until fuel started to fail.
Under the new EAL scheme, an Alert would be declared immediately and 1
a' Site Area Emergency 15 minutes later. To the extent that this head start allows more time _for.offsite authorities to prepare for-the ultimate evacuation of_the public, there is a benefit. Since non-essential onsite' personnel are evacuated at the' Site Area Emergency, there would also be a benefit to them.
If tne containment were to f ail sooner than predicted or the evacuation took longer than estimated, under the old EAL scheme some members of the public could be caugnt in the plume while under the new scheme this is much less likely.
f.
A consioeration of important qualitative factors bearing on the-need for the backfit at the particular f acility, such as, but not limited to, operational trends, significant plant events, management effectiveness.
or results of performance reports such as the Systematic Assessment of Licensee Performance.
The prelicensing inspection revealed a problem with implementation of the WCGS EAL scheme.
In addition, a January 26-30, 1987 emergency preparedness exercise revealed a potential for significant delays in making appropriate protective action recommendations for the public under the old WCGS EAL classification procedure.
Inspection Report 50-4B2/87-04 states: e
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"The DEM deiayed making protective action recommendations af ter plant-conoitions (e.g., claa f ailure and core uncovering at 9:59 a.m.; 3.5 percent concentration of hydrogen in the containment at 10:30 a.m.;
continuous pressure buildup in the containment building; large LOCA and loss of coolant inventory) warranted it. The DEM postponed making Jprotective action recomendations for the public at risk, even af ter the NRC' Emergency Response Team informed him that in their opinion general emergency conditions were present (10:23 a.m.).
The decision for sneltering personnel within the center zone was not recommended by the DEM until 11:10 a.m.
At that time, the county decided for evacuation of numanpopulationsattnecenterzone(50-482/8704-04)."
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A, statement affirming appropriate interoffice-coordination related to the
_ proposeo backfit ano the plan for implementation.
The backtit was coordinated by the Region IV office with representetives of the NRR Emergency Planning Branch, and the NRR Project Manager in etcendance and in agreement.
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The basis ior requiring or permitting implementation on a particular schedule,
. including sufficient information to demonstrate that the schedules are realistic ano provide adequate time for in-depth engineering, evaluation, design, procurement, installation, testing, development of operating procedures, and training of operators and other plant personnel, as appropriate.
For those plants with approved integrated schedules, the integrated scheduling process can be used for implementing this step and the'following two procedural steps.
. Actual implementation of the backfit was at the licensee's pace over a period of a year or more.
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A schedule f or staf f actions involved in implementation and verification of' implementation of the backtit, as appropriate.
The backfit nas been implemented ano inspected by the Regica IV office, j.
Importance of tne proposed backfit consicered in light of other
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safety-related activities underway at the aff ected f acility.
The backfit was accomplished at a deliberate pace consistent with its perceived s af ety ' significance. The safety implications in the interim were mitigated by
- NRC regional and headquarters staff awareness of the limitations of the old
=WCG5' scheme.
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A statement of the consideration of the proposed plant-specific backfit as a-potential generic backtit.
As a backfit, this was not generic because WCGS had the only " approved" pure fission product barrier seneme. One other licensee attempted to implement an~
identical scheme under 10 CFR 50.54(q) but it was not approved by the NRC. We have not had other applications for the pure fission product barrier schemes although approved hybrid (i.e., event based-fission product barrier) EAL schemes are in place at several licensees including WCGS.
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