ML20117P646
| ML20117P646 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/20/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20117P644 | List: |
| References | |
| NUDOCS 9609240402 | |
| Download: ML20117P646 (7) | |
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'4 UNITED STATES j
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2000H001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT ND.184 TO FACILITY OPERATING LICENSE NO. DPR-51 ENTERGY OPERATIONS. INC.
l ARKANSAS NUCLEAR ONE. LERIT NO.1 l
DOCKET NO. 50-313
1.0 INTRODUCTION
By letter dated May 19, 1995, as supplemented by letters dated July 21, 1995, and June 10, September 10 and 13, 1996, Entergy Operations, Inc. (the licensee) submitted a request for changes to the Arkansas Nuclear One, Unit No.1 (ANO-1) Technical Specifications (TSs). The requested changes would revise the technical specifications to permit the reactor building personnel airlocks to be open during fuel handling operations.
The July 21, 1995, and June 10, September 10 and 13,1996, letters provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
The containment at ANO-1 is provided with a personnel airlock, a personnel escape (emergency) airlock, an equipment hatch and other penetrations for piping and cables. The airlocks are provided with double doors to permit access while maintaining containment integrity. The double doors are provided with interlocks to ensure tnat only one door at a time can be open.
Per the existing specification, during cold shutdown and refueling the interlocks may be disabled and both doors may be opened, if irradiated fuel is not being moved in containment.
2.0 BACKGROUND
On August 31, 1994, the staff issued amendments to the Calvert Cliffs Nuclear Power Plant TSs revising the TSs to permit both doors in the personnel airlock to be open during fuel handling.
Prior to issuance of that amendment, at least one of the two doors was required to be closed during fuel handling.
Approval of the Calvert Cliffs amendments was based on:
(1) the findings of an analysis of radiological consequences of a fuel handling accident (FHA) that the calculated radiological doses are acceptable, and (2) commitments by the licensee that would ensure that containment closure would be promptly established following containment evacuation, in the event of an FHA.
Subsequently, similar applications were received and approved for other facilities.
It is the staff's policy to approve such applications if l
(1) confirmatory dose calculations by the staff indicate acceptable l
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9609240402 960920 PDR ADOCK 05000313 P
, radiological consequences and (2) the licensee has committed to implement administrative procedures that ensure that the open airlock can and will be promptly closed following containment evacuation in the event of a refueling accident (even though the containment fission product control function is not required to meet acceptable dose consequences criteria).
By application dated May 19, 1995, Entergy Operations, Inc. (the licensee) requested similar amendments for Arkansas Nuclear One, Units 1 and 2 (ANO-1 and ANO-2). Following review of supporting calculations associated with the consequences of a fuel handling accident, the staff on September 28, 1995, issued the amendment for ANO-2. By letter dated July 21, ?995, the licensee provided a cammitment for ANO-1 and ANO-2 to designate an individual at the open door to monitor the condition of the opened airlock during fuel handling and to assure closure of the airlock following containment evacuation. This commitment was acceptable for ANO-2, however, since that time, the NRC has decided that the commitment should be properly codifief, in the TSs. By letter dated September 10, 1996, the licensee provided the proposed TSs for ANO-1.
Additional information was needed for the ANO-1 review and by letters dated June 10 and September 13, 1996, the licensee provided analyses to support the assumption that only six rows of rods (82 fuel rods) are damaged in the drop.
The proposed ANO-1 amendment would revise the TSs to permit both doors in the personnel airlock to be open during handling of irradiated fuel in the j
containment as follows:
u TS 3.8.6 will be revised to reflect that at least one door on the e
emergency and personnel airlocks shall be capable of being closed during handling of irradiated fuel in the reactor building.
Administrative procedures must be established to:
a.
ensure that appropriate personnel are aware of the OPEN status of the containment during core alterations and fuel handling, b.
ensure that an open airlock is capable of rapid closure with quick disconnect and removal capability for hoses, cables, ramps, and door seal protective covers, and c.
ensure that an individal is designated and readily available to close the airlock following the evacuation that would occur in the event of an accident.
TS 3.8.6 is also revised to require at least 23 feet of water be maintained over the top of irradiated fuel seated within the pressure vessel during irradiated fuel handlir:Q.
t TS 3.8.11 is revised to require that irradiated fuel not be removed from the reactor vessel until the unit has been subcritical for at least 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />. The previous limit was 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
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! i The bases are modified to reflec, the above changes.
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The staff has evaluated the application to confirm that (1) confirmatory dose calculations indicate acceptable radiological consequences without taking credit for the containment's fission product control function, and (2) the j
licensee has adequate TSs that ensure that the open airlock can and will be l
promptly closed, following containment evacuation, in the event of a refueling l
accident.
The licensee's initial application did not explicitly confirm that l-administrative controls would be implemented to ensure that an open airlock can and would be promptly closed in the event of a fuel handling accident in the containment. After discussions with the staff, the licensee provided a letter dated July 21, 1995, stating that when the airlocks are opened during fuel handling and core alterations, an individual will be assigned to monitor the status of the door and close it following containment evacuation.
i Procedures will be implemented to ensure that the airlock passages are not i
obstructed in such a manner as to inhibit prompt closure. ANO-2 received it's l
September 28, 1995, amendment to operate on the basis of a commitment, however, the NRC now requires these provisions as part of the TSs. The licensee has proposed TSs in the September 10, 1996, letter for ANO-1.
j 3.0 EVALUATIONS The NRC staff has established the following generic criteria for the acceptance of proposed amendments that would allow both doors of the i
containment personnel airlock (PAL) to be open during fuel movement and core alterations:
1.
The radiological consequences for a fuel handling accident in containment (FHAIC) must meet Standard Review Plan (SRP) 15.7.4 acceptance criteria without credit for the mitigation effects of the primary containment.
l 2.
Administrative procedures must be established to:
a.
ensure that appropriate personnel are aware of the OPEN status of the containment during core alterations and fuel handling, i
b.
ensure that an open airlock is capable of rapid closure with quick disconnect and removal capability for hoses, cables, ramps, and door I
seal protective covers, and ensure that an individual is designated and readily available to l
c.
l close the airlock following the evacuation that would occur in the 1
event of an accident.
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i During core alterations and refueling operations, a FHAIC is the limiting i
event postulated for the purpose of design of accident mitigation features.
l This design basis accident assumes that a spent fuel bundle is dropped and j
fuel rods are ruptured. The licensee performed an analysis of a FHAIC with
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the airlock doors open.
In performing the analysis, the licensee used the assumptions in Regulatory Guide (RG) 1.4, and the review procedures specified in RG 1.25, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage j
Facility for Boiling and Pressurized Water Reactors." The licensee provided an analysis showing that only six rows of fuel pins (82 pins) would be damaged in the drop. The staff reviewed the licensee's analysis in the ANO-1 Safety j
Analysis Report (SAR), Section 14.2.2.3, Fuel' Handling Accident.
The staff concludes that the licensee's analysis is adequate to justify the number of fuel rods (six rows) assumed to be damaged in the fuel handling accident. A 100-hour decay time (TS 3.8.11), and 23 feet of water coverage (TS 3.8.6) are assumed in the analysis.
No credit is taken for the potential mitigating effects of the engineered safety feature (ESF) filtration system provided for the auxiliary building. The licensee's analysis demonstrated that the 0-2 hour site boundary thyroid dose will be 64 rem and the 0-2 hour whole body site boundary dose will be 0.9 rem. These calculated doses are within the SRP criteria of 75 rem to the thyroid and 6 rem to the whole body (WB). The licensee initially reported the doses to the control room personnel as being bounded by the loss-of-coolant-accident (LOCA) analysis for both ANO units. The LOCA doses are reported in Table 15.1.13-2 in the ANO-2 Safety Analysis Report as 20.7 rem to the thyroid and 1.12 rem to the whole body.
In discussions, the licensee indicated that the fuel handling accident in ANO-1 with 82 pins damaged in the fall would give control room doses of 3.28 rem to the thyroid and 0.026 rem to the whole body. These calculated doses to the control room personnel are within the appropriate dose acceptance criteria of General Design Criterion (GDC) 19.
The staff has completed its evaluation of the potential radiological consequences of a FHA at ANO-1 based upon the conditions of the proposed TS changes.
In addition to reviewing the licensee's submittal, the staff performed an independent analysis to confirm conformance with the acceptance criteria of 10 CFR Part 100 and GDC 19 of Appendix A to 10 CFR Part 50. The staff's analysis utilized the accident source term given in RG 1.4, the assumptions contained in RG 1.25, and the review procedures specified in SRP Sections 15.7.4 and 6.4.
The staff further assumed an instantaneous puff release of noble gases and radiciodines from the gap and plenum of the broken fuel rods. These released gas bubbics will pass through at least 23 feet of water covering the fuel, prior to reaching the containment atmosphere. All airborne activity reaching the containment atmosphere is assumed to exhaust to the environment within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. As stipulated in the proposed TS change, the activity of the gases in the fuel gap and plenum is assumed to have decayed for a period of 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />.
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t The staff computed the offsite doses for ANO-1 using the assumptions described above and NRC's ACTICODE computer code. Control room operator doses were i
determined using the methodology in Section 6.4, including the use of the Murphy-Campe meteorological factors. The computed offsite doses and control room operator doses are within the acceptance criteria given in SRP Section 15.7.4 and GDC 19. The resulting calculated values and the assumptions used in calculating those doses are presented in Tables 1 and 2.
The staff's dose calculation was based on the assumption that all of the radioactive material released to the containment escapes the containment within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. However, the staff has historically required plant TSs to i
maintain containment closure during core alterations and fuel handling as a defense-in-depth measure. Recently the staff has allowed channes to plant TSs to keep both doors to a containment airlock open during core a' terations and fuel handling. These changes contained provisions to close one door quickly, thereby reestablishing containment closure. The licensee proposed similar controls to reestablish containment closure for ANO-1. Administrative controls for TS 3.8.6 will ensure (1) that appropriate personnel will be readily available to close the airlock in the event of a FHA and (2) that any cables or hoses running through the open airlock will be designed for quick removal.
Therefore, the proposed administrative controls provide reasonable assurance that containment closure as a defense-in-depth measure can be reestablished quickly to limit releases much lower than assumed in the dose calculations.
TABLE 1 CALCULATED RADIOLOGICAL CONSE0VENCES (rem)
Exclusion Area Boundary Egig SRP 15.7.4 Guidelines Thyroid 52 75 l
Whole Body 0.2 6
Control Room Operator Qqig GDC-19 Guidelines j
Thyroid 2.5 Equivalent to 5 rem whole body *
.l Whole Body
<0.1 5
the thyroid.
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. TABLE 2 ASSUMPTIONS USED FOR CALCULATING RADIOLOGICAL CONSE0VENCES l-I Parameters Ouantity Power Level (Mwt) 2568 Number of Fuel Rods Damaged 82 i
Total Number of Fuel Rods 36816 Shutdown time, hours 100 Power Peaking Factor
- 1.65 Fission Product Release Duration 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Release Fractions
- Iodine 12%
Noble Gases 10%
Krypton Gas 30%
Iodine Forms
- Elemental 75%
Organic 25%
Core Fission Product Inventories per TID-14844 Receptor Point Variables Exclusion Area Boundary
- 3 Atmosphere Relative Concentration, X/Q (sec/M )
0-2 hours 6.8 x 10
Control Room Atmospheric Relative Concentration, X/Q (sec/m )
5.6 x 10-3 3
Control Room Volume, cubic feet 1.8 x 10' Recirculation Flow, cubic feet minute 1667 Unfiltered inleakage cubic feet minute 10 Iodine Protection Factor 144 Geometry Factor 33 Regulatory Guide 1.25 Note: Dose conversion factor from ICRP-30 were utilized for all calculations.
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4.0 TECHNICAL SLM1ARY l
The staff concluded that the radiological consequences associated with a FHA L
at ANO-1 during refueling operations with the containment airlocks open are l
within the acceptance criteria set forth in 10 CFR Part 100 and GDC 19 of Appendix A to 10 CFR Part 50. Additionally, administrative controls are in
. place to reduce the calculated radiological release substantially, if not completely, by closing the open airlock doors promptly after a FHA.
The staff, therefore, concludes that the proposed amendment is acceptable for ANO-1.
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5.0 STATE CONSULTATION
In accordance with the Comission's regulations, the Arkansas State official was notified of the proposed issuance of the amendment. The State official had no comments.
6.0 ENVIRONMENTAL CONFIDERATION 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 effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public coment on such finding (60 FR 39437). 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.
7.0 CONCLUSION
The Commission has concluded, bued 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 Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
J. Minns Date: September 20, 1996 I
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