IR 05000482/1984025
| ML20235G348 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 07/07/1987 |
| From: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Withers B WOLF CREEK NUCLEAR OPERATING CORP. |
| References | |
| RTR-NUREG-0654, RTR-NUREG-654 NUDOCS 8707140213 | |
| Download: ML20235G348 (5) | |
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JUL 7 1987 In Reply Refer To:
Docket:
STN 50-482 Wolf Creek Nuclear Operating Corporation ATTN:
Bart D. Withers President and Chief Executive Officer P. O. Box 411 Burlington, Kansas 66839
Subject:
Deficiencies in Wolf Creek Generating Station Emergency Classification Schemes In September 1984, NRC and certain contractors inspected the Wolf Creek Generating Station (WCGS) to determine the plant's emergency preparedness for licensing.
(NRC Inspection Report STN 50-482/84-25.) As indicated in that inspection, walk-throughs were used to determine the ability of control room j
personnel to implement the WCGS Emergency Plan.
The walk-throughs revealed deficiencies in implementation and also potential deficiencies in the Plan. Due to the Plan's novel approach to emergency classification, its potential weaknesses were identified at that time as an
" Improvement Item" rather than a " Deficiency." Specifically, Improvement Item 482/8425-92 recommended that all of the applicable initiating conditions specified in Appendix I of NUREG-0654 be included in EPP 01-2.1.
In retrospect, NRC's concern was understated.
It appears now that the NUREG-0654 initiating conditions have not been and perhaps cannot be accommodated by the WCGS Plan. This became evident during the NRC's January 26-30, 1987 emergency preparedness inspection during an annual exercise.
(Inspection Report 50-482/87-04)
Our concern that the WCGS Plan might be inadequate was heightened by the observation that:
"The DEM delayed making protective action recommendations af ter plant conditions (e.g., clad failure 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 protective action recommendations for the public at risk, even after the NRC Emergency Response Team informed him that in their opinion general emergency conditions were present (10:23 a.m.).
The decision for sheltering 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 human populations at the center zone (50-482/8704-04)."
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Wolf Creek Nuclear Operating Corp.
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To evaluate our concern, an NRC contractor was asked to review the WCGS EAL and classification scheme.
The enclosed summary of the review explains the Plan weaknesses that prevent WCGS from accomplishing the goals of NUREG-0654.
In short, the WCGS EALs can be expected to result in an emergency declaration of lower severity, or the same severity at a much later time than EALs prepared under the guidance in NUREG-0654.
Thus, the WCGS emergency classification scheme does not provide the equivalent level of protection that the guidance in NUREG-0654, if followed, would provide.
In addition, the WCGS EAL scheme does not include several example events of NUREG-0654, such as the loss of function needed for shutdown, security events, loss of power, natural events, and evacuation of the control room.
These are classified initially as unusual events, but are not escalated unless a fission product barrier is breached or a breach is imminent.
(Improvement Item 482/8425-92)
The enclosed summary is supported by detailed comments, not enclosed with this letter, which we would like to discuss with appropriate WCGS representatives in the Region IV Office at 9:00 a.m. on July 29, 1987. The goal of the meeting will be a mutually agreeable schedule for upgrading the Plan and EPIPs to achieve the level of protection intended by NUREG-0654.
Sincerely,
/f3/
Eric H. Johnson, Director Division of Reactor Safety and Projects cc w/ enclosure:
Wolf Creek Nuclear Operating Corporation ATTN: Otto Maynard, Manager of Licensing P. O. Box 411 Burlington, Kansas 66839 Gary Boyer, Plant Manager Wolf Creek Nuclear Operating Corporation P. O. Box 411 Burlington, Kansas 66839 Forrest Rhodes, Vice President, Nuclear Operations Wolf Creek Nuclear Operating Corporation P. O. Box 411 Burlington, Kansas 66839 Kansas Radiation Control Program Director bcc:
(see next page)
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Wolf Creek Nuclear Operating Corp.
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bcc distrib. by RIV:
RPB Myron Karman, ELD, MNBB (1)
RRI R. D. Martin, RA
. Section Chief (RPB/B)
DRSP RPSB R. P. Warnick, RIII RIV File Resident Inspector, RIII MIS System RSB RSTS Operator Project Inspector, RPB D. Weiss, RM/ALF R. Hall NRR Project Manager D. B. Matthews, NRR C. A. Hackney W. L. Fisher R. L. Bangart FEMA Region 7
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Enclosure SUM' MARY REVIEW OF WOLF CREEK GENERATING STAT?ON (WCGS)
EMikGENCY CLASSIFICATION SCHEMES i
The WCGS EAL scheme was reviewed against the regulatory requirements of 10 CFR 50.47(b)(4) and the guidance of NUREG-06E4/ FEMA-REP-1, Rev. 1, Appendix 1.
The WCGS classification procedure includes an event-oriented system for makir.g Notification of Unusual Event declarations, and a " symptomatic" scheme for the higher classifications.
This scheme analyzes event symptoms (i.e., instrument indications) that are " symptomatic" of the challenge or breach of the three fission product barriers (fuel clad, reactor coolant system, and containment).
No event-based EALs are included in the classifications of Alert or higher. An i
equivalency is established such that the challenge or breach of one fission
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product barrier constitutes an Alert, two barriers a Site Area Emergency, and three barriers a General Emergency.
However, in the absence of fuel or RCS barrier failure, a failure of containment is an Unusual Event.
A' direct correlation between the WCGS classification scheme and the NUREG-0654, Appendix 1, Example Initiating Conditions is not possible.
Most Appendix A, Unusual Event conditions are addressed by the WCGS scheme.
However, the conservative, early alerting intent of NUREG-0654 has been modified frequently in the WCGS scheme by adding a provision that if the applicable Action Statement of the Technical Specification can be met (e.g., " shutdown within 8 hrs"), then an emergency declaration will not be made.
Most Appendix 1, Alert, Site Area Emergency, and General Emergency example conditions of NUREG-0654 are omitted or are not directly addressed by the WCGS scheme.
In some cases, the more severe Appendix 1 conditions of Alert and Site Area ~ Emergency are classified as Unusual Events.
Many of the symptomatic EALs of the Alert and higher classifications are not quantified and objective, but are subjective, such as
" increase significantly" and " pervasive condition of high radiation intensity."
Although an emergency classification system with four degrees of severity has been implemented by the licensee, the scheme of EALs supporting the classifications is not consistent with the intent of NUREG-0654 A
mechanistic failure of the fission product barrier (s) must be observable by the plant emergency director, or a classification will not be declared.
As an example, a total loss of AC power is classified as an Unusual Event, without regard to time.
The licensee's philosophy is that since, by itself, a loss of
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Enclosure-2-power will not cause a loss of fission product barriers, a Site Area Emergency will not be declared 15 minutes after icss of all AC power, as NUREG-0654 recommends. According to the WCGS scheme, the loss of power alone does not provide the mechanism for failure of two fission product barriers; thus, a Site Area Emergency declaration is not warranted.
Further degradation that directly impacts the fission product barrier must occur before a Site Area Emergency will be declared.
A significant nonconservative aspect of the WCGS classification scheme is the
" Phase 2" concept, wherein a prediction is made of the time to failure of the next fission product barrier, the estimated evacuation time is subtracted, and the resultant interval is considered the time available to the operators to mitigate the event. The emergency classification corresponding to breach of that barrier is not declared unless the " interval" elapses without mitigation of the event. The licensee considers this delay in escalating the emergency classification necessary to avoid needlessly activating offsite authorities and the public, if mitigating efforts are effective.
In adopting this philosophy, the licensee's methodology does not retain the conservative, anticipatory intrnt of NUREG-0654.
Furthermore, the licensee's methodology does not include several example events of NUREG-0654 that are not readily classified with a purely symptomatic approach, such as the loss of power described above, loss of function needed for shutdown, security events, natural events, and "other" hazards. Until the " event" challenges or fails a fission product barrier, the " event" is always an " Unusual Event." Utilizing the symptomatic scheme as implemented by the licensee to analyze the events of NUREG-0654 usually results in an emergency declaration of the same severity level at a much later time than using the event-oriented schemes or a combination of symptomatic and event-oriented schemes employed by other utilities.
The procedure organization is unwieldy, due to listing of various combinations of barrier failure for the Site Area Emergency and not listing the EALs that constitute each of the three barrier failures / challenges.
This results in inconsistencies in the EALs for f ailure of the RCS barrier for Alert and for Site Area Emergency. The EALs should be the same. Additionally, the procedure does not consider inability to monitor a barrier as a challenge / failure of the barrier (e.g., the loss of valve position indication on containment isolation valves).