[Federal Register Volume 62, Number 176 (Thursday, September 11, 1997)]
[Notices]
[Pages 47835-47838]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24219]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-390]


Tennessee Valley Authority Watts Bar Nuclear Plant, UNIT 1; 
Environmental Assessment and Finding of No Significant Impact

    The U.S. Nuclear Regulatory Commission (the Commission or NRC) is 
considering issuance of an amendment to Facility Operating License No. 
NPF-90, issued to Tennessee Valley Authority (TVA), for operation of 
the Watts Bar Nuclear Plant, Unit 1 (WBN), located in Rhea County, 
Tennessee.

Environmental Assessment

Identification of the Proposed Action

    TVA has requested a change to the current WBN Technical 
Specifications (TSs) to provide for insertion of four lead test 
assemblies (LTAs) containing 32 tritium producing burnable absorber 
rods (TPBARs) into the WBN reactor during Fuel Cycle 2. After a single 
cycle of operation the TPBARs will be removed from the reactor and 
stored in the spent fuel pool. Then the TPBARs will be placed in 
shipping casks and transported off-site under Department of Energy 
(DOE) control.

The Need for the Proposed Action

    As discussed in the NRC staff report, NUREG-1607, ``Safety 
Evaluation Report related to the Department of Energy's proposal for 
the irradiation of lead test assemblies containing tritium-producing 
burnable absorber rods in commercial light-water reactors,'' May 1997, 
DOE is responsible for establishing the capability to produce

[[Page 47836]]

tritium, an essential material used in U.S. nuclear weapons, by the end 
of 2005, in accordance with a Presidential decision directive. Tritium 
is an isotope of hydrogen that decays at a rate of approximately 5 
percent per year (a 12.3-year half-life). The United States has not 
produced tritium for use in nuclear weapons since 1988, when DOE closed 
its production facility at Savannah River. Resumption of tritium 
production for weapons will be essential for maintaining the U.S. 
nuclear weapons stockpile and the U.S. nuclear deterrent. DOE has 
selected a dual-path strategy to meet its schedule, one of which 
proposes to produce tritium in commercial light water reactors (CLWRs), 
either through acquisition of reactor(s) under Government ownership or 
by contracting for target irradiation services at a plant under private 
ownership.
    DOE has developed a design for burnable poison rods using lithium, 
rather than the boron which is currently used in reactor fuel 
assemblies. As a result of irradiation by neutrons in the rector core, 
some of the lithium in the target rods would be converted to tritium. 
The irradiated burnable poison rods can then be removed from the fuel 
assemblies and shipped to another location for tritium extraction. The 
first phase of the tritium program involving CLWRs is a lead test 
assembly (LTA) demonstration. LTA irradiation would serve as a 
confirmatory test of the design for TPBARs that DOE has developed over 
the past 10 years. For this purpose, DOE has selected TVA as a host 
utility to perform LTA irradiation. Accordingly, TVA proposes to insert 
four LTAs into the WBN reactor during Fuel Cycle 2 to provide 
irradiation services to support DOE investigations into the feasibility 
of using commercial light water reactors to maintain the nation's 
inventory of tritium. The proposed action is in accordance with TVA's 
application for amendment dated April 30, 1997, as supplemented by 
letters dated June 18, July 21 (3 letters), and August 7 and 21, 1997.

Alternatives to the Proposed Action

    As stated in the NRC staff report, NUREG-1607, the second phase of 
DOE's tritium production program that would involve CLWRs and require 
NRC review would be DOE's submittal of a topical report for production 
irradiation in mid-1998. The staff plans to initiate review of that 
report concurrently with the irradiation of the LTAs and anticipates 
that it will document its review in a safety evaluation report to be 
issued in early 1999. DOE has stated that, because the primary purpose 
of the LTA demonstration is to build confidence among prospective 
licensees, completion of the LTA demonstration is not an essential 
precursor to submittal of the topical report. The NRC staff could 
initiate review of the production topical report independent of the LTA 
demonstration. However, the staff may need information from the LTA 
demonstration before it can complete its review of the production 
topical report.

No Action Taken

    The principal alternative would be to take no action to approve the 
LTA program in the WBN during Fuel Cycle 2. That alternative would 
avoid any environmental impacts which may be associated with this 
action, but as indicated herein, there are no significant environmental 
impacts associated with this action. Denial of this proposed action 
would have the result that further CLWR tritium production activities, 
including any NRC staff review of subsequent proposals for production 
of tritium in a CLWR, would then be made without the benefit of the 
results of the LTA program. This could result in additional 
uncertainties affecting DOE's choice of alternatives in the tritium 
production program, as well as the NRC staff's review, and is not 
considered a desirable option.

Environmental Impacts of the Proposed Action

Radiological Impact
    The WBN has waste treatment systems designed to collect and process 
waste that may contain radioactive material. The radioactive waste 
treatment systems were evaluated in the WBN Final Environmental 
Statement (FES) and its supplement. Results are reported in Tables 5.2 
and 5.3 of NUREG-0498, Supplement 1, April 1995. The proposed amendment 
will not involve any change in the radioactive waste treatment systems 
or flowrates described in the FES and its supplement.
    Tritium produces less dose per unit of radioactivity taken into the 
human body than many other nuclides because tritium (a) decays by the 
emission of a low-energy beta radiation, (b) passes through the human 
body in a short period of time, and (c) does not concentrate in a 
single organ. Furthermore, tritium in liquid effluents from Watts Bar 
is diluted to a relative low concentration before it reaches even the 
most highly exposed member of the public; i.e. the release of the 
entire 214 Ci (7.93 TBq) in a year's cooling water would produce an 
average concentration of only about 0.24 pCi/gm (8.9 Bq/kg) in the 
receiving water. Consequently, the maximum annual dose to a member of 
the public would be less than 0.02 mrem (0.2 micro-Sievert). This dose 
is less than 1 percent of the NRC criterion for liquid effluents and 
only about 0.007 percent of the average annual dose resulting from 
naturally occurring radionuclides.
    The tritium would be further diluted before it reached the 
substantial number of people (about 216,000) residing in population 
centers downstream of Watts Bar so the resulting individual doses would 
be small, averaging about 0.4 micro-rem (4 nano-Sievert). The resulting 
population dose would be less than 0.09 person-rem (person-cSv).
    A portion of the tritium might be released to the atmosphere. The 
amount would depend on plant conditions and the manner in which it is 
operated. If the entire 214 Ci (7.93 TBq) were released to the 
atmosphere, individuals could be exposed via a variety of pathways. 
These pathways include inhalation and skin absorption, as well as the 
consumption of meat, vegetables and milk. The total dose by all 
pathways to the most highly exposed member of the public is calculated 
to be less than 0.05 mrem (0.50 micro-Sievert). This is less than 1 
percent of the NRC criterion for airborne effluents and less than 0.02 
percent of the average person's annual dose resulting from naturally 
occurring radionuclides.
    Tritium in the atmosphere also could reach the more highly 
populated areas in the vicinity of Watts Bar, but the airborne tritium 
would be diluted even more than would water-borne tritium. Thus the 
population dose would be smaller from a release to the atmosphere than 
from a release to the river.
    It is concluded that the releases from Watts Bar, and the resulting 
off-site doses, will not be significantly affected by releases of 
tritium from the TPBPRs.
    The proposed amendment is not expected to significantly affect the 
doses to the workers in the fuel storage area. The TPBARs are designed 
to have minimal effect on plant operations, including refueling 
operations. Since the unirradiated TPBARs are essentially not 
radioactive, they will produce no increase in exposure, occupational or 
non-occupational. After irradiation, the TPBARs are expected to contain 
some 370,000 Ci (13.7 PBq) of tritium (\3\H). This is far more tritium, 
but far less radioactivity, than that produced by the reactor core. The 
tritium does not pose a particular threat because (1) tritium emits 
only a low-energy (Emax= 18.6 keV) beta and (2) the tritium 
is bound in the TPBARs. Some of the tritium beta

[[Page 47837]]

energy is converted into x-rays (bremsstrahlung) but 370,000 Ci of 
tritium produces less photon energy than is produced by 1 Ci (37 GBq) 
of 137 Cs and the 137 Cs radiation is much more 
penetrating. The spent fuel removed for refueling contains about a 
million curies of 137 Cs and many other nuclides. Thus, the 
effect of tritium as a source of external radiation in the reactor 
environment is negligible.
    The TPBARs are designed to minimize the leakage of tritium and DOE 
experience indicates that leakage will be less than 6.7 Ci (0.248 TBq) 
per rod annually. If all 32 of the TPBARs were to leak at this rate, 
the annual tritium release to the reactor coolant would be less than 
214 Ci (7.93 TBq). This quantity is consistent with the nominal amounts 
of tritium expected in pressurized water reactor (PWR) coolant systems. 
The NRC licensing calculation, the GALE code, predicts about 250 Ci 
(9.25 TBq) of tritium in the reactor coolant and tritium releases to 
the environment from large PWRs are averaging over 600 Ci (22.2 TBq) 
per year per reactor and ranging as high as 4,000 Ci (148 TBq) per year 
without exceeding regulatory limits. Thus, the TPBARs might produce an 
observable but not dramatic increase in the tritium concentration in 
the spent fuel pool. Increasing the tritium in the spent fuel pool 
could increase occupational exposure but, since tritium exposure is not 
an important contributor to occupational exposure (according to NRC 
data summarized in NUREG-0713, ``Occupational Radiation Exposure at 
Commercial Nuclear Power Reactors and Other Facilities, 1995'', January 
1997), the increase would be expected to be negligible. This is 
consistent with the results reported in the DOE report.
    The staff concludes that the TPBARs could cause some increase in 
occupational radiation exposure. However, this increase would be 
negligible and would not constitute a safety, or an ``as low as is 
reasonably achievable'' (ALARA) concern.
    Based on the above, the staff concludes that there are no 
significant radiological environmental impacts associated with the 
proposal.
Non-Radiological Impact
    The proposal does not affect non-radiological plant effluents and 
no changes to the National Pollution Discharge Elimination System 
(NPDES) permit are needed. The proposal does not result in any 
significant changes to land use or water use, or result in any 
significant changes to the quantity or quality of effluents and no 
effects on endangered or threatened species or on their habitat are 
expected. Therefore, no changes or different types of non-radiological 
environmental impacts are expected as a result of the amendment.

Accident Considerations

    In its application, TVA evaluated the possible consequences of 
postulated accidents and described the means for mitigating these 
consequences should they occur. This evaluation included the effects of 
a TPBAR on postulated accidents, including a TPBAR assembly dropped 
during refueling, radiological consequences of release of reactor 
coolant (steam generator tube rupture or steamline break), and TPBAR 
damage and radiological consequences during a design-basis loss-of-
coolant accident (LOCA). On the basis of its analysis, TVA concluded 
that the effect of the TPBAR on accident consequences would be small 
and that the calculated consequences are within regulatory requirements 
and staff guideline dose values.
    As TVA has reported in its application and the staff has previously 
evaluated in NUREG-1607, there are increases in the potential 
radiological consequences resulting from a design basis LOCA; and the 
LOCA is the most limiting accident with regard to TPBAR failure. The 
DOE report states that the effect of TPBARs and the additional tritium 
on the combustible gas inventory following a LOCA is negligible. In 
addition, the maximum stored inventory of tritium in TPBAR LTAs is a 
very small fraction of the hydrogen that would be released from a 
zirconium-water reaction. Consequently, TPBARs would have no 
significant contribution to combustible gas in a LOCA. The tritium 
released to the coolant would not be released as a gas and, therefore, 
would not produce an increase in hydrogen concentration. The resulting 
dose at the exclusion area boundary would be about 0.3 mrem (3 
Sv). The potential increase in the offsite radiological 
consequence as a result of accidents has been determined to be 
negligible. The environmental impacts of any credible accidents are 
found not to be significant.
Summary
    The Commission has completed its evaluation of the proposed action. 
The change will not significantly increase the probability or 
consequences of accidents, no changes are being made in the types and 
no significant increases are being made in the amounts of any effluents 
that may be released offsite, and there is no significant increase in 
the allowable individual offsite dose or cumulative occupational 
radiation exposure. Accordingly, the Commission concludes that there 
are no significant radiological environmental impacts associated with 
the proposed action.
    With regard to potential nonradiological impacts, the proposed 
action involves features located entirely within the restricted area as 
defined in 10 CFR Part 20. It does not affect nonradiological plant 
effluents and has no other environmental impact. Accordingly, the 
Commission concludes that there are no significant nonradiological 
environmental impacts associated with the proposed action.
Alternative Use of Resources
    This action does not involve the use of any resources not 
previously considered in the FES for WBN Units 1 and 2, dated April 
1995.
Agencies and Persons Consulted
    In accordance with its stated policy, on August 20, 1997 the staff 
consulted with the Tennessee State official, Mr. Eddy Nanney, of the 
Division of Radiological Health, regarding the environmental impact of 
the proposed action. The State official indicated that TVA and NRC 
should consider very carefully anything designed and fabricated by DOE 
that is to be put into the Watts Bar reactor. As stated herein, the NRC 
staff does believe that its review carefully considers the impacts of 
inserting the LTAs containing the TPBARs into Watts Bar during Fuel 
Cycle 2.

Finding of No Significant Impact

    The staff has reviewed the proposed lead test assembly program at 
WBN relative to the requirements set forth in 10 CFR Part 51. Based 
upon its environmental assessment, the staff has concluded that there 
are no significant radiological or non-radiological impacts associated 
with the proposed action and that the proposed license amendment will 
not have a significant effect on the quality of the human environment. 
Therefore, the Commission has determined, pursuant to 10 CFR 51.31, not 
to prepare an environmental impact statement for the proposed 
amendment.
    For further details with respect to the proposed action, see the 
licensee's letter dated April 30, 1997, as supplemented by letters 
dated June 18, July 21 (3 letters), August 7 and 21, 1997, which are 
available for public inspection at the Commission's Public Document 
Room, The Gelman Building, 2120 L Street, NW., Washington, DC, and at 
the local public document room located at the Chattanooga-Hamilton 
County Library, 1001 Broad Street, Chattanooga, Tennessee.


[[Page 47838]]


    Dated at Rockville, Maryland, this 8th day of September 1997.

    For the Nuclear Regulatory Commission.
Frederick J. Hebdon,
Director, Project Directorate II-3, Division of Reactor Projects--I/II.
[FR Doc. 97-24219 Filed 9-10-97; 8:45 am]
BILLING CODE 7590-01-P