ML20050B620
| ML20050B620 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 04/01/1982 |
| From: | Vandewalle D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20050B621 | List: |
| References | |
| GL-81-10, NUDOCS 8204060144 | |
| Download: ML20050B620 (5) | |
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Dennis M Crutchfield, Chief C,,
gg Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - SHIFT MANNING'.
EVA1UATION a
Enclosed are copies of two reports, " Assessment of Shift Staffing Requirements for the Big Rock Point Nuclear Plant", attachment 1, and " Operator Action Event Trees for the Big Rock Point Nuclear Plant", attachment 2.
Both of these reports were prepared for the purpose of providing a detailed PRA based evaluation of operator actions and skills required to respond effectivly to 4
transient and accident conditions at the Big Rock Point Plant.
The reports are provided in response to Generic Letter 81-10, dated February 18, 1981. Addressed to licensees of all operating plants, the NRC Generic Letter provided the. staff's position with respect to emergency response and included an endorsement of the on-site shift staffing levels recommended by NUREG-0654 for nuclear power plant emergencies. Repeating the minimum on-shift staffing level presented in these documents:
lct)T 1 Shift Supervisor (SRO) 1 Shift Foreman (SRO)
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2 Control Room Operators (RO)
/ pQ 2 Auxiliary Operators 1 Shift Technical Advisor 1 HP Technician 1 Rad / Chem Technician 1 Individual responsible for notification / communication 10 Minimum Total O.
In the 19 years of operating experience obtained at the Big Rock Point Plant, staffing to this level of on-shif t personnel had never been identified as 8204060144 820401 PDR ADOCK 05000155 PDR p
D M Crutchfield, Chief 2
Big Rock Point Plant Shift Manning Evaluation
,_s April 1, 1982 necessary.
Implementation of the staffing requirements of the Generic Letter would double the size of the shif t previously demonstrated to be adequate to safely and efficiently operate the plant.
Responding to Generic Letter 81-10 on April 8, 1981 Consumers Power Company notified the NRC that these minimum staffing requirements would not be met at Big Rock Point. This notification came shortly after formal submittal of the Probabilistic Risk Assessment which was based on historical shift staffing levels and did not explicitly identify the need to expand the shift in the manner required by the staff. Expansion of our position on Big Rock Point was provided on June 22 and July 7,1981 in the proposal of the following seven man shift:
1 Shift Supervisor (SRO) 2 Reactor Operator (RO) 2 Auxiliary Operators 1 HP-Rad / Pro Technician
_1_ Shift Technical Advisor 7 Minimum Total In these proposals, the Shif t Supervisor was responsible for insuring notification / communication duties are performed until the Site Emergency Director arrives and assumes these functions.
(As described in our January 11, 1982 submittal, our intent to relieve the Shift Supervisor of these s
responsibilities was specified by training a Security Officer to perform the required notifications until relieved by the Site Emergency Director.) In addition, our proposal stated that the on-shift position of Shift Technical Advisor was provisional pending' completion of an evaluation of staffing levels required to respond effectively to emergency situations.
This evaluation is now complete and is submitted for your review in the form the attached reports by Wood-Leaver and Associates, Inc.
These reports include 27 Operator Action Event Trees (OAET) developed using the methodology of NUREG/CR-1440, " Light Water Reactor Status Monitoring During Accident Sequence Conditions." The Operator Action Event Trees identify operator and maintenance activities which are potentially required to respond to and mitigate each of the more than eighty dominant accident sequences identified in the Big Rock Point PRA. These dominant sequences were tho9e which were quantified to have a probability of occurrence greater than 10 / year. The completeness of the 27 OAET's in adequately addressing operator and maintenance functions for all of the dominant sequences is developed and presented as a part of the reports.
An evaluation of all operator and maintenance activities identified in the OAETs is made to determine a) the time frame in which the actions are required; b) the time required to perform the action; c) skills required to perform the action; and d) the environmental conditions in which the action must be performed. Having determined the skills required as a function of time for each sequence further evaluation of on-shif t and on-call staffing needs is made.
It is assumed for this evaluation that those skills required oc0382-0041a142
D M Crutchfield, Chief 3
Big Rock Point Plant Shift Manning Evaluation March 31, 1982 early in the accident or transient sequence (ie, afi hr) need to be available on-shift to be effective. Those required late during the stages of a sequence (ie, ;> hours) are considered effective if they are available on-call. Every maintenance and operator action identified in the Operator Action Event Trees was classified in one of these two time frames.
A comparison of these skills as a function of time to existing on-shift and on-call staffing was made to evaluate the adequacy of current staffing levels.
Where skills were identified as being beneficial in responding to a dominant sequence but were not available in a timely manner within the plant staff as i
it exists, cost benefit analysis of providing personnel to fill these positions was performed.
The results of these evaluations are presented in dr. ail within the report.
These results can be summarized as follows:
The OAET evaluation of the plant as it is currently designed, concludes that all dominant accident sequences can be responded to effectively with the following plant staff:
1 Shift Supervisor (SRO) 2 Reactor Operators (RO) 2 Auxiliary Operators 1 HP-Rad / Chem Technician
-s 2 Security Guards (for the purpose of filling required
)
___ positions on the five-man fire brigade) g 8 Minimum Total The evaluation did not indicate a direct benefit in the mitigation of accident and transient sequences of staffing the following positions:
1 Shift Foreman (second SRO) 4 1 Shift Technical Advisor 1 Individual de 'icated to notification / communications responsibilities Further, the activities identified for the HP-Rad / Chem Technician within the early stages of a sequence were limited and primarily directed at the health physics / radiation protection aspects of his position. The limited chemical analyses associated with accident mitigation which can be performed at Big Rock Point occur late in the course of the sequence. These activities can be j
timely and adequately nerformed by on-call personnel substantiating our position that a single individual can provide a combined HP-Rad / Chem function on shift.
Consumers Power Company realizes the benefits of effective emergency notification in providing timely communication with appropriate individuals and off-site agencies during an accident or transient. Operator Action Event Tree Methodology does not readily lend itself to quantifying these benefits.
However, the results of this study indicates that the Shif t Supervisor is not an appropriate individual to be responsible for these duties early in a oc0382-0041a142
D M Crutchfield, Chief 4
Big Rock Point Plant Shif t Manning Evaluation
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April 1, 1982
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transient or accident sequence and that a potentially substantial benefit can be obtained by relieving him of notification activities. Consumers Power Company intends, as stated in our January 11, 1981 letter, to provide an individual not normally associated with accident mitigation functions to perform notifications / communications duties. Until the Site Emergency Director arrives and is able to relieve him, the notification function will be provided by a trained on-shift Security Officer.
With respect to the STA position Consumers Power Company has decided to maintain individuals on an on-call status. The Operator Action Event Trees do not demonstrate any direct benefit in the mitigation of accident and transient sequences. However, for personnel development and training, Consumers Power Company will continue to qualify a large portion of the plant's technical support staff in the areas of plant systems, PRA dominant accident and transient sequences and plant operating procedures. These individuals will serve on an on-call basis to support plant operations as necessary. This on-call status will be included in the Big Rock Point Plant Emergency Plan Implementing Procedures.
In conclusion, Generic Letter 81-10 recommends a shif t staffing level which is significantly greater than that historically required or than any which can be employed effectively at Big Rock Point. The size of the plant is accommodated in a reduced Emergency Planning Zone as compared to larger facilities.
However, the simplicity in the design of the plant and its size also have an tT effect on the manner in which transients and accidents progress, the time
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frame over which they progress, as well as operator and maintenance actions which can be accomplished in mitigation of the transients as they progress.
Generic application of the staffing recommendations of NUREG-0654 does not accommodate the differences in the size and design of Big Rock Point from larger facilities.
Consumers Power Company recognizes the need for on-shif t and on-call staffing which assures effective response to accident and transient situations.
It should also be recognized, however, that it is unreasonable to require staffing levels for all postulated accident scenarios regardless of their liklihood. Accident scenarios can be conceived though probabilistically insignificant which could overwhelm the size and skills of any proposed staff including that recommended by the NRC.
Therefore, Consumers Power Company has taken the initiative to provide a detailed technical evaluation on which the staffing of the Big Rock Point Plant will be based. This evaluation uses the Probabilistic Risk Assessment as its basis providing some assurance that staffing requirements are derived from relatively conceivable accident situations as well as accommodating the plants unique design. The methodology which is used in this evaluation involves the development of Operator Action Event Trees as is described in NUREG-CR-1440. This methodology provides a unique, logical and complete tool with which issues such as shift staffing can be explained. Using the OAET tool in this manner, Consumers Power Company concludes the Big Rock Point Plant staff it proposes is adequate to accommodate all of the dominant accident sequences identified in the PRA.
These sequences include all those f) with a probability of occurrence greater than once every ten million years.
v oc0382-0041al42
D M Crutchfield, Chief 5
Big Rock Point Plant 7s Shift Manning Evaluation April 1, 1982 As plant design changes occur and as new safety issues arise, this tool can be used to re-evaluate shift staffing requirements as well as other issues.
In the near future, Consumers Power Company will submit a Technical Specifica-tion revision which reflects the results of the attached evaluation.
In particular, this change will remove the STA from the shif t and place him on a 24-hour on-call basis.
We believe the attached reports represent a unique use of probabilistic techniques in dealing with an important regulatory issue. As such, we would like to ensure that the staff and its consultants have a relatively good understanding of the Operator Action Event Trees and know they were used in the evaluation of Big Rock Point shif t staffing requirements. Consumers Power Company proposes a presentation to appropriate members of the staff and its consultants at your convenience to discuss Big Rock Point staffing and 0AET methodology. We suggest that the meeting be held at the Big Rock Point Plant to allow the reviewers to walk through several accident sequences and possibly interview several plant operations personnel. We believe such a meeting will be beneficial for both assuring the NRC staffs consideration of our proposal as well as increasing understanding on the use of the Big Rock Point PRA in the regulatory environment.
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%dJ2 ad b David J andeWalle Nuclear Licensing Administrator CC Administrator, Region III, USNRC NRC Resident Inspector-Big Rock Point Attachments - 2 i
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