ML19211A251
| ML19211A251 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, Zion  |
| Issue date: | 11/21/1979 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912170261 | |
| Download: ML19211A251 (3) | |
Text
... %
/ } lr/ % 0 LJ /% / L4& -
S'O & Y
'[
Io,
+
UNITED STATES
/
N 8
NUCLEAR REGULATORY COMMISSION e,
g g
'. t WASHINGTON, D. C. 20555 NOVEMBER 2 1 1979
%.....p MEMORANDUM FOR:
Harold R. Denton, Director Of fice of Nuclear Reactor Regulation FROM:
Darrell G. Eisenhut, Acting Director Division of Operating Reactors
SUBJECT:
PROPOSED TASK FORCE TO REVIEW INDIAN POINT 2/3 AND ZION 1/2 BACKGROUND:
Following the Three Mile Island accident, the staff recognized an urgent need to conduct an in-depth review of the emergency preparedness capabilities of all nuclear power plants.
In July 1979, criteria were identified for upgrading the capabilities of such facilities and the goals for implementation. When this review effort along with implementation of the short term lessons learned actions are completed, it is believed that the ability of plant operators to determine the severity and follow the course of an accident as well as the responsiveness by various levels of government officials to an accident will be greatly enhanced.
Two operating nuclear power plant sites, however, because of the' location in areas of high population density, are considered to warrant a more in-depth and separate review to cetermine if the need exists for additional measures to further reduce the probability of a severe accident and to reduce the consequences of such an event, lhese two sites are at the Indian Point 2/3 and Zion 1/2 f acilities located near New York City and Chicago, respectively. A risk to the public, which is high relative to other operating nuclear power plant sites, is believed to exist because of the difficulties of evacuating large numbers of people in a short time period during an emergency and because of the additional potential health effects resulting from accidents of very low likelihood for which emergency actions would not be completely successful at any site.
PROPOSED PLAN In response to your request, we have outlined a review of the Indian Point 2/3 and Zion 1/2 facilities to study various alternatives that would be effective in reducing the probability and consequences of a severe accident. We propose that such a review be conducted by a small task group and would include a consideration of both preventive means as well as those for mitigating the consequences of a severe accident. Accordingly, we have developed a preliminary Action Plan cutlining such a re tiew effort. The plan is based upon the utilization of a multidiscipline review group involving other NRC Offices (principally RES and IE). The results of the group's efforts, while initially directed at Indian Point 2/3 and Zion 1/2, would have general applicability to other plants and sites.
1591 247 H.Mya
Harold R. Denton NOVEMBER 2 1 1979 The basic structure of the plan for these specific plants, is three fold:
(1) improved operational actions, (2) current licensing actions, and (3) an evaluation of various mitigating design features. The actions that are involved in items (1) and (2) are mainly directed toward accident prevention, whereas (3) deals principally with mitigation of the potential consequences of an unlikely but severe accident.
(1) Improved Interim Operational Actions: These actions involve, but are not necessarily limited to, such considerations as increased IE inspections, additional resident inspectors, augmented control room staffing and improved operator qualifications and training. Selected aspects from the Long Term Lessons Learned Report (NUREG-0585) may also be included as measures to further reduce the likelihood of a severe accident, e.g., corporate management accountability. In addition, a review of the emergency procedures would be included to improve operational capabilities. This effort will also include an examination of the derating of the plant during an interim period while the actions in items (2) and (3) below are reviewed.
(2) Current Licensing Actions:
The actions involved in this aspect of the plan will include implementation on a priority basis of those TM1-2 short term lessons learned actions stated in NUREG-0578 and Bulletin and Order review matters.
In addition prompt attention will be given to processing of outstanding amendments for these plants.
Subsequent actions would include implementation of any recommendations resulting from the resolution of unresolved safety items on a priority basis.
(3) Severe Accident Mitigation Features:
In addition to the increased preventive actions described in (1) and (2) above, there are several measures that may be effective in mitigating the consequences of a major reactor accident involving core melt. Additional means such as derating and measures to augment the existing ECCS via an independent system are considerations that fall between prevention and mitigation and may be effective agents against a major nuclear accident. Such means also would include a bunkered system with a dedicated heat removal system.
Present considerations for severe accident mitigation include such features as a core catcher (e.g., magnesium oxide), hydrogen control measures, and filtered containment venting.
These features, either singly or in combination could delay or prevent containment failure and provide varying degrees of protection against an early release of large quantities of fission products from the containment if a major accident involving a core melt should occur. Delaying the 1591 248
,h0VEMBER 21579 Harold R. Denton,
release of large quantities of fission products from the containment provides additional time to implement effective emergency plans and actions in regions aroung the subject plants as well as other plants where evacuations may become necessary in the event of a major nuclear accident. While all of the mitigation measures described have neither been fully evaluated nor developed sufficiently to quantify either their feasibility or effectiveness, the state-of-the-art technology appears adequate so that they may be given preliminary consideration for the indicateo applications.
To better assess their effectiveness, analyses would be necessary to bound such related core melt phenomena as steam and hydrogen explosions and the release of noncondensibles from the interaction between core melt products and the concrete basemat. These aspects as well as containment failure modes would be included in the overall studies of selected scenarios that would apply to several core melt type accidents.
Over the last week, we have had several NRC staff discussions and have developed the foregoing discussion that is in effect a proposed program.
We have also called the three affected licensees to inform them that this preliminary review is under way. We will also consider ACRS involvement as the program develops further.
We antir.jpate meeting with the three licensees involvea to discuss this prograra in general during the week of November 26 or December 3,1979. We will keep you informed as our program becomes more efined.
l sen u.,
{
I ing 0 rector re 2.
Division o Operating Reactors cc:
E. Case D. Vassallo R. Mattson S. Hanauer D. Ross 1591 249 D. Muller S. Levine T. Murley N. Moseley V. Stello R. Tedesco T. Telforo T. Speis