[Federal Register Volume 64, Number 226 (Wednesday, November 24, 1999)]
[Notices]
[Pages 66213-66214]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30645]
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NUCLEAR REGULATORY COMMISSION
Revised Criteria for Post Accident Sampling Systems
AGENCY: Nuclear Regulatory Commission.
ACTION: Request for comment.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is considering
modifying its criteria for post accident sampling systems (PASS). The
NRC has received two industry-developed topical reports which provide
justification for removal of PASS from the licensing basis for nuclear
power plants designed by Westinghouse and Combustion Engineering. The
NRC generally agrees with the conclusions in these reports and is
considering approving these reports. If the NRC approves these reports,
nuclear power plant licensees will be able to reference the reports to
support changes to their PASS, including the elimination of the system.
The NRC is requesting public comment on this pending action. In
particular, the NRC is seeking comment on whether the elimination of
information obtained from radionuclide sampling from PASS may affect
offsite emergency response organizations ability to respond to an
accident.
DATES: The comment period expires January 10, 2000. Comments received
from after this date will be considered if it practical to do so, but
the Commission is able to ensure consideration only for comments
received on or before this date.
ADDRESSES: Submit comments to: David L. Meyer, Chief, Rules and
Directives Branch, U.S. Nuclear Regulatory Commission, Washington, DC,
20555-0001, Attention: Rulemakings and Adjucations Staff.
Deliver comments to: 11555 Rockville Pike, Rockville, Maryland,
between 7:30 a.m. and 4:15 p.m. on Federal workdays.
The publications cited in this document, including the industry-
developed topical reports, are available for inspection and copying,
for a fee, through the NRC Public Document Room, 2120 L Street, Lower
Level, Washington, DC.
FOR FURTHER INFORMATION CONTACT: James O'Brien, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC.
20555-0001, telephone (301) 415-2919; e-mail [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
II. Description of Proposed Action
III. Evaluation of Proposed Action
IV. Request for Comment
I. Background
Following the accident at Three Mile Island Unit 2 (TMI-2) on March
28, 1979, the NRC formed a lessons-learned Task Force to identify and
evaluate safety concerns originating with the TMI-2 accident. NUREG-
0578, ``TMI-2 Lessons Learned Task Force Status report and Short-term
Recommendations,'' documents the results of the task force effort. One
of the recommendations of the task force was for licensees to upgrade
the capability to obtain samples from the reactor coolant system and
containment atmosphere under high radioactivity conditions and to
provide the capability for chemical and spectral analyses of high-level
samples on site. NUREG-0737, ``Clarification of TMI Action Plan
Requirements,'' which was issued to licenses in Generic Letter 80-90 on
October 31, 1980, contains the details of the TMI recommendations that
were to be implemented by the licensees. Additional criteria for post
accident sampling systems were issued by Regulatory Guide 1.97,
``Instrumentation for Light-water-cooled Nuclear Power Plants to Assess
Plant and Environs Conditions During and Following an Accident.''
Specific criteria for PASS capability delineated in NUREG-0737 and
Regulatory Guide 1.97 are:
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Sample location Measurement
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1. Reactor Coolant..................... Dissolved gases, Boron,
Chlorides, pH, Radionuclides
2. Containment Atmosphere.............. Hydrogen, Oxygen, Radionuclides
3. Containment Sump.................... Boron, Chlorides, pH,
Radionuclides
------------------------------------------------------------------------
All samples and measurements were to be taken and analyzed within 3
hours of the decision to do so except for chlorides which were to be
taken and analyzed within 24 hours.
In the mid 1980's, the NRC sponsored an assessment of selected
regulatory requirements that may have marginal importance to risk. One
of the issues reviewed was the PASS criteria. This assessment,
documented in NUREG/CR-4330, concluded that the PASS had marginal
benefits, but that the cost of maintaining the PASS was minimal.
On October 26, 1998, the Westinghouse Owners Group submitted a
topical report, WCAP-14986-P which provided justification for
elimination of the PASS from the licensing basis. By eliminating PASS
from the licensing basis, there would no longer be a licensee
commitment to maintain the system. On May 5, 1999, the Combustion
Engineering Owners Group
[[Page 66214]]
submitted a related topical report, CE NPSD-1157, which also provided
justification for elimination of PASS. Both of these topical reports
indicated that the cost of maintaining the PASS was high and justified
elimination of PASS based upon there being no benefit in the
information obtained via PASS. The topical reports conclude that the
sampling systems are not useful in supporting post accident mitigative
and emergency response actions and that most of the information, which
would be obtained from sampling, can be inferred from other indications
which will be available earlier in an event that the sample results. In
addition, the topical reports state that the samples are subject to
inaccuracies due to physical phenomena (e.g., deposition of fission
products in sample lines) involved in taking the samples.
II. Description of Proposed Action
The NRC is proposing to endorse the industry topical reports for
referencing in site-specific licensing actions to remove commitments
for maintaining PASS. This action, if taken, would allow nuclear power
plants to remove their commitments for maintaining PASS.
III. Justification for Proposed Action
The NRC concludes from its review of the topical reports that the
information to be obtained from PASS can be inferred to a large degree
from other indications which will be available earlier in an event than
the PASS samples due to the time needed to obtain and analyze the PASS
sample. In addition, the PASS samples are difficult to obtain and are
subject to inaccuracies due to physical phenomena (e.g., deposition of
fission products in sample lines) involved in taking the samples.
However, PASS can provide a measurement of radionuclides in reactor
coolant system, containment sump and containment atmosphere which may
be used in supporting emergency response decision making. This
information may be used to modify the assumed source term used in
offsite dose calculations which are considered in formulating
Protective Action Recommendations (PARs) during an accident. This
information is not needed to formulate initial PARs (which are most
likely based on plant conditions, e.g., reactor water level, core
temperatures, and containment radiation levels). Furthermore, other
information, such as area, process, and effluent radiation monitor
readings and field team data, can be used to support modification to
the initial PAR. The PASS information would potentially be most useful
in situations where an accident results in release of radioactive
material to the reactor coolant or containment, but a breach of either
of these systems/volumes does not occur within the first several hours
of the accident or occurs through an unmonitored release path. However,
even in these situations, PASS sample measurement information would not
be a real-time indication of the concentration of radionuclides within
the sampled volume (due to the time needed to analyze the samples) and
would be subject to the inaccuracies discussed above.
IV. Request for Comment
Before completing its review of the industry topical reports, the
NRC is seeking public comment from its stockholders. In particular, the
NRC is seeking comment from offsite emergency response organizations
who may have an interest in information regarding radionuclide
concentrations in the reactor coolant, containment sump or containment
atmosphere to support their emergency response activities (in
particular protective action decision making). Specifically, the NRC is
seeking comment on whether elimination of information obtained from
radionuclide sampling using the PASS may have an adverse effect on
offsite emergency response organizations' ability to respond to an
accident in view of (1) the availability of information provided by
plant conditions, plant radiation monitor readings and field monitoring
teams and (2) the limitations associated with the accuracy and
timeliness of information provided by the PASS.
Dated at Rockville, Maryland, this 18 day of November, 1999.
For the Nuclear Regulatory Commission.
Frank P. Gillespie,
Deputy Director, Division of Inspection Program Management, Office of
Nuclear Reactor Regulation.
[FR Doc 99-30645 Filed 11-23-99; 8:45 am]
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