ML20078S796
| ML20078S796 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/22/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078S792 | List: |
| References | |
| NUDOCS 9502270201 | |
| Download: ML20078S796 (4) | |
Text
- .
\\
- 49 t
UNITED STATES J
y-g j
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066 4 001
% * * * * * [g SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.105 TO FACILITY OPERATING LICENSE NO. NPF-49 NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 DOCKET NO. 50-423
1.0 INTRODUCTION
By letter dated May 18, 1994, the Northeast Nuclear Energy Company (the licensee), submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 3 Technical Specifications (TS). The requested changes would more clearly define the period when the fuel building exhaust filter system is to be operable. Section 9.4.2.2 of the FSAR for Millstone 3 states that " fuel building filtration is required whenever heavy loads (fuel or other) are moved within or over the spent fuel pool and less than 60-day (decay time) fuel is in the pool." Operation of the filter system during other periods is considered unnecessary and will decrease charcoal adsorption efficiency.
The proposed amendment will result in a modification of the applicability, surveillance requirement, and bases sections to TS 3/4.9.12, " Fuel Building Exhaust Filter System."
The 3p.olicability section will be revised to state that the fuel building exhaust filter system is required to be operable whenever irradiated fuel with a decay time of less then 60 days is in the spent fuel pool.
TS 3.9.12, " Applicability," which currently reads:
Whenever irradiated fuel is in the storage pool.
will be revised to read:
Whenever irradiated fuel with less than 60 days decay is in the storage pool.
The surveillance reauirement will be revised to require that the system be tested and verified operable no more than 31 days preceding its required use.
The fuel building exhaust filter system is required to be operable wheriever irradiated fuel that has decayed less than 60 days is in the pool.
9502270201 950222 PDR ADOCK 05000423 P
~
, TS 4.9.12 which currently reads:
At least once per 31 days on a STAGGERED TEST BASIS by initiating, from the control room, flow through the HEPA filters and charcoal adsorbers and verifying a system flow that the system operates for at least 10 continuous hours with the heaters operating.
will be revised to read:
Within 31 days prior to moving fuel within or loads over the storage pool when irradiated fuel with less than 60 days decay is present by initiating, from the control room, flow through the HEPA filters and charcoal adsorbers, and verifying a system flow rate of 1
20,700 cfm 10% and that the system operates for at least 10 continuous hours with the heaters operating.
The bases section will be revised to reflect the key assumptions and results of the offsite dose calculation.
TS 3/4.9.12 will be revised to read:
The limitations on the Fuel Building Exhaust Filter System ensure that all radioactive iodine released from an irradiated ~ fuel assembly and storage pool water will be filtered through the HEPA filters and charcoal adsorber prior to discharge to the atmosphere. Operation of the system with the heaters operating for at least 10 continuous hours in a 31-day period is sufficient to reduce the buildup of moisture on the adsorbers and HEPA filters. The OPERABILITY of this system and the resulting iodine removal capacity are consistent with the assumptions of the safety analyses. ANSI N510-1980 will be used as a procedural guide for surveillance testing. The filtration system removes radiciodine following a fuel handling or heavy load drop accident. Noble gases would not be removed by the system. Other radionuclides would be scrubbed by the storage pool water.
Iodine-131 has the longest half-life:
-8 days. After 60 days decay time, there is essentially negligible iodine and filtration is unnecessary.
i 2.0 EVALUATION i
The staff evaluated the changes to Millstone 3 TS 3/4.9.12, " Fuel Building Exhaust Filter System," proposed by the licensee to modify the operability requirements for the fuel building exhaust filter system.
Currently, the system is required to be operable whenever irradiated fuel is in the spent fuel pool.
In addition, the surveillance requirement requires that the system be verified operable every 31 days. The proposed modification will require that the system be operable whenever irradiated fuel which has decayed,less
M
, than 60 days is in the spent fuel pool.
It will also require that the system be verified operable within 31 days of load movement or fuel movement over the pool that contains fuel which has decayed less than 60 days.
The licensee has reassessed the consequences of a fuel handling accident at two intervals:
(1) with irradiated fuel (decayed for 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />) in the pool and operation of the fuel building exhaust filter system, and (2) with irradiated fuel (decayed for 60 days) in the pool and no operation of the fuel building exhaust filter system.
The results of the licensee's calculated offsite thyroid doses are shown in Table 1 along with the staff's calculations. The offsite dose calculation for a 60-day decay time is significantly lower than for a 100-hour decay time.
All of the calculated doses are within the acceptance criterion of 75 rem stated in NUREG-0800, Section 15.7.4, " Radiological Consequences of Fuel Handling Accidents." Therefore, the staff finds that the licensee's proposed TS changes are acceptable.
TABLE 1 Offsite Dose Calculations for Thyroid Doses frem)
Decay Time 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> 60 days Staff Evaluation 1.8 (0.018 sievert) 0.36 (0.0036 sievert)
Licensee h (valuation E
- FSAR, 7.6 (0.076 sievert) 1.5 (0.015 sievert)
=
Section 9.4.2.2) i Acceptance Criterion (NUREG-0800, 75 (0.75 sievert) 75 (0.75 sievert)
Section 15.7.4)
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
g z
, 4.0 ENVIR0fMENTAL CONSIDERATION The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation. exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (59 FR 32234). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the
~
public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: J Minns Date: February 22, 1995 o
..