ML20196K482
| ML20196K482 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 07/06/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20196K479 | List: |
| References | |
| NUDOCS 9907080389 | |
| Download: ML20196K482 (7) | |
Text
I f tioq t UNITED STATES
[ j NUCLEAR REGULATORY COMMISSION
" t WASHINGTON, D.C. 20566-0001
. . . . . ,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION MAINE YANKEE ATOMIC POWER COMPANY MAINE YANKEE ATOMIC POWER STATION DOCKET NO. 50-309
1.0 INTRODUCTION
By letter of September 25,1997, Maine Yankee Atomic Power Company (MYAPC or the licensee) asked the Nuclear Regulatory Commission (NRC) to remove confirmatory orders issued by the NRC dated July 10,1981; March 14,1983; June 14,1984; and January 3,1996, because they are no longer warranted given the permanently shutdown and permanently defueled condition of the Maine Yankee Atomic Power Station (MYAPS).
2.0 EVALUATION On August 6,1997, the MYAPC Board of Directors decided to permanently cease further operation of the MYAPS. On August 7,1997, in accordance with 10 CFR 50.82(a)(1), MYAPC presented to the NRC certifications of permanent cessation of operations and permanent removal of fuel from the reactor vessel. These certifications modified the MYAPS license so that operation of the reactor and emplacement of fuelinto the reactor vessel are no longer authorized. in its letter of September 25,1997, the licensee proposed to eliminate several confirmatory orders that it believed were inappropriate for the permanently shutdown and defueled condition of the MYAPS facility. MYAPC stated that elimination of these provisions will allow plant staff to focus on those license provisions that are appropriate to the permanently shutdown and defueled plant conditions. The proposed changes are evaluated in the paragraphs that follow.
Confirmatory Order dated July 10.1981 This order confirmed licensee commitments relative to post-Three Mile Island (post-TMI) issues identified in NUREG-0737, Supplement 1. These requirements were relative to the prevention I and mitigation of postulated accidents and emergency preparedness associated with plant l operation. The licensee stated that this order is no longer appropriate in the permanently shutdown and defueled plant conditions and should be rescinded. The requirements of this order are discussed separately below.
9907000389 990706 PDR ADOCK 05000309 l W PDR c L.
4 (A) Shift technical advisor (STA) coversos and lona-term trainina oroaram. With the plant in a permanently shutdown and defueled condition, the type and complexity of potential accidents have been significantly reduced. Present technical specifications do not require an STA on shift when the plant is in a cold shutdown mode. The need for an STA
' has been eliminated. The licensee submitted proposed technical specification changes to permanently eliminate STA coverage. The licensee also submitted a Certified Fuel Handier Training Program and related changes to technical specifications to allow the training program to focus on the safe storage and handling of spent fuel. NRC approved these proposals in November 1997.
(B) Uoaraded operator trainina oroaram.' With the plant in a permanently shutdown and defueled condition, the operator training program is no longer warranted except as related to the safe storage and handling of spent fuel. As indicated above, NRC approved a Certified Fuel Handler Training Program and related changes to technical specifications to allow the training program to focus on the safe storage and handling of spent fuel.
(C) ' Accident procedures. With the plant in a permanently shutdown and defueled condition, there are no longer any credible design-basis accidents associated with an operating plant from startup through full-power operation. The design-basis accidants related to a permanently defueled facility are a small subset of those accidents considered for an operating facility. Those accident procedures that are in response to accidents associated with an operating plant are no longer necessary. This includes all the emergency operating procedures (EOPs) and most of the abnormal operating procedures (AOPs).
'(D) Imolementino orocedures for feedback of ooeratina exoerience. ' With the plant in a permanently shutdown and defueled condition, procedures for the feedback of operating experience are not warranted.
(E) Vital area shieldina. With the plant in a permanently shutdown and defueled condition, design-basis accidents that could make it necessary to shield remaining vital areas are not possible. Therefore, no vital area shielding is necessary.
(F) Egit-accident samolin.g. With the plant in a permanently shutdown and defueled condition, post-accident sampling of the RCS and containment atmosphere is not required.
(G) ' Trainina to mitiaate core damaae. With the plant in a permanently shutdown and defueled condition, the unit can no longer suffer core damage from an operating event.
' (H)- Performance testina of relief valves and safety relief valves. With the plant in a 1 permanently shutdown and defueled condition, this testing is no longer warranted.
(1) . Auxiliary feedwater initiation and flow. With the plant in a permanently shutdown and defueled condition, auxiliary feedwater is no longer needed.
l (J). Containment isolation oressure setooint With the plant in a permanently shutdown and defueled condition, containment isolation is no longer needed. ,
(K) Post-accident noble ans monitor and lodine /narticulate samolina. With the plant in a 1 permanently shutdown and defueled condition, postulated accidents that would warrant sampling of the reactor coolant system (RCS) are no longer possible.
(L)- inadeounte core cooling instrumentation With the plant in a permanently shutdown and defueled condition, design-basis accidents that could result in inadequate core cooling in the reactor vessel are no longer possible.
(M) Rooort on small-break loss-of-coolant accident (SBLOCA) and probability of failure of power ooerated relief valve / safety valve / relief valve (PORV/SV/RV). This report has been completed. Furthermore, these issues are no longer relevant as these components serve no function in the permanently shutdown and permanently defueled plant condition.
-(N) Reoort on safety relief valve and relief valve failures and challenoes. This report has been completed. Furthermore, these issues are no longer relevant as these components serve no function in the permanently shutdown and permanently defualed plant condition.
(O) Reoort on ECCS outanes. This report has been completed. Furthermore, these issues are no longer relevant as these components serve no function in t' 3 permanently )
shutdown and permanently defueled plant condition. l (P) Proaram for SBLOCA methodg. This program has been submitted. Furthermore, small-break loss-of-coolant accidents of the reactor coolant system are no longer possible.
I (Q) Post-accident in-olant iodine monitorina. With the plant in a permanently shutdown and defueled plant condition, the only design-basis accident that could result in the release of radioactive iodine is a fuel handling accident and, there' ore, the likelihood of a large release of radioactive iodine is significantly reduced. The longest lived iodine isotope, 1-131, has a half-life of 8.06 days. After 10 half-lives, a materialis considered to have decayed to a negligible quantity, as less than 0.1 percent of the initial material remains. j For 1-131,10 half-lives are reached after approximately 81 days. With a minimum decay time of the spent fuel of more than 24 months (730 days), the potential source term associated with a design-basis fuel handling accicent to which the plant continues to be vulnerable has been significantly reduced (to negligible levels) since the plant last operated. The reduced potential source term no longer warrants in-plant radioactive iodine monitoring capability.
(R) Contro! room habitability. With the plant in a permanently shutdown and defueled
- condition, the design-basis accidents that require the control room to be staffed and that would threaten the habitability of the control room are no longer possible. With the plant having been shut down for more than 24 months, the potential source term associated with a design-basis fuel handling accident to which the plant continues to be vulnerable does not challenge the habitability of the control room. Continued protection against
- other postulated incidents that could threaten the habitability of the control room (i.e.,
I hazardous gas release) are no longer warranted in the defueled plant condition. In the
l 1
defueled plant condition, continuous occupation of the control room is no longer necessary to ensure the safe handling and storage of spent fuel, and the control room could be evacuated, if necessary, in the event of a release of hazardous chemicals requiring such evacuation, without affecting the stored fuel.
The staff has determined that because of the permanently shutdown and defueled status of the l MYAPS facility, the requirements of this order are no longer necessary for safe operation or i maintenance of the plant. It is the staff's assessment that the rescission of this order does not pose any decrease in safety or any increase in the probability of accidents applicable in the permanently shutdown and defueled condition. Therefore, the staff finds rescission of the confirmatory order dated July 10,1981, acceptable.
Confirmatory Order dated March 14.1983 This order confirmed licensee commitments relative to post-TMl issues identified in NUREG-0737, Supplement 1. These requirements were primarily relative to the prevention and mitigation of postulated accidents and emergency preparedness associated with plant operotion, and not the remaining accidents identified in the FSAR to which the plant continues its vulnerability in its current condition. Therefore, the licensee stated that this order is inappropriate to the permanently shutdown and defueled plant condition and should be rescinded. The requirements of this order are discussed separately below.
(A) Simulator exams in operator license exams. With the plant in a permanently shutdown l and defueled condition, continued use of the plant simulator is no longer warranted.
(B) Plant shieldina for access to vital areas. With the plant in a permanently shutdown and defueled condition, postulated design-basis accidents that warrant shielding to remaining vital areas are no longer possible.
(C) Uoaraded post-accident samolina eauipment. With the plant in a permanently shutdown and defueled plant condition, design-basis accidents that warrant sampling of the reactor ,
coolant system (RCS) are no longer possible.
(D) Trainina for miticatina core damaag. With the plant in a permanently shutdown and defueled condition, core damage in the reactor vessel is no longer possible.
(E) Auxiliarv feedwater flow instrumentation to steam aenerator. With the plant in a permanently shutdown and defueled plant condition, auxiliary feedwater flow is no longer required.
(F) Lower containment oressure setooint. With the plant in a permanently shutdown and defueled condition, containment isolation is no longer required.
(G) Purae and vent valves on radiation sianal. With the plant in a permanently shutdown and defueled condition, the purge and vent valves are no longer required to function automatically.
e L
(H) Noble gas emuent monitors With the plant in a permanently shutdown and defueled condition, most design-basis accidents are no longer possible. The potential source term associate? with the remaining design-basis accidents to which the plant continues to be vulnerable has been significantly reduced by more than 24 months of radioactive decay
'since the plant last operated. Therefore, the capability to monitor noble gas from a postulated ful handling accident is no longer warranted.
(l) Effluent monitorina of iodine. With the plant in a permanently shutdown and defueled condition, most design-basis accidents are no longer possible. The potential source term associated with the remaining design-basis accidents to which the plant continues to be vulnerable (1-131, which undergoes 10 half-lives of decay in approximately 81 days) has
- been significantly reduced to negligible levels by more than 24 months (730 days) of radioactive decay since the plant last operated. Therefore, the capability to monitor iodine from a postulated fuel handling accident is no longer warranted.
(J) In-containment rediation monitor. With the plant in a permanently shutdown and defueled condition, most design-basis accidents are no longer possible. The potential source term associated with the remaining design-basis accidents to which the plant continues to be vulnerable has been significantly reduced by more than 24 months of radioactive decay since the plant last operated. Therefore, the continued requirement for an in-containment radiation monitor is not warranted.
(K)- Containment pressure indication. With the plant in a permanently shutdown and defueled condition, containment isolation is no longer required.
(L) Containment water level indication. With the plant in a permanently shutdown and defueled condition, conP'nment isolation is no longer required.
(M) Containment hydronen concentration. With the plant in a permanently shutdown and defueled condition, hydrogen generation from metal-water reaction is no longer possible.
(N) Eplicy on overtime limit. With the plant in a permanently shutdown and defueled plant condition, the need to have a limit on overtime for safety-related activities has been sharply reduced. Overtime limit policy is also addressed in the technical specifications.
In March 1998, the NRC approved a prnposed change to these technical specifications to better reflect the defueled plant condition. Overtime policies are discussed in Section 5.2.2 of the technical specifications (O) Reoort on the relief and safety valve oroaram. This report has been submitted.
(P) Report on the block valve test oroaram. This report has been submitted.
(Q) Control room habitability modifications. In a permanently shutdown and defueled condition, and with the plant having been shut down for more than 24 months, the design-basis accidents that require the control room to be staffed and that would threaten l
t the habitability of the control room are no longer possible. Continued protection against j other postulated incidents that could threaten the habitability of the control room are no longer warranted, since the control room could be safely evacuated if required.
The staff has determined that because of the permanently shutdown and defueled status of the MYAPS facility, the requirements of this order are no longer necessary for safe operation or maintenance of the plant. It is the staff's assessment that the rescission of this order does not pose any decrease in safety or any increase in the probability of accidents applicable in the
- permanently shutdown and defueled condition. Therefore, the staff finds rescission of the confirmatory order dated March 14,1983, acceptable.
Confirmatory Order dated June 14.1984 j l
This order confirmed licensee commitments relative to post-TMl issues identified in NUREG- I 0737, Supplement 1. These requirements were primarily relative to the prevention and mitigation of postulated accidents and emergency preparedness associated with plant i operation, and not the remaining accidents identified in the FSAR, to which the plant continues i its vulnerability in its current condition. Other requirements related to emergency preparedness are found in 10 CFR 50.47 and Appendix E to 10 CFR Part 50, forwhich MYAPC requested exemption in a separate request that was granted by the NRC in September 1998. Therefore, ,
the licensee stated that this order is no longer appropriate in the permanently shutdown and i defueled plant condition and should be rescinded. The requirements of this order are i discussed separately below. j i
(A) Safety parameter display system With the plant in a permanently shutdown and !
defueled condition, the safety parameter display system is no longer required. Postulated l design-basis accidents that would warrant its use are no longer possible.
(B). ' Detailed control room desian review. With the plant in a permanently shutdown and defueled condition, most of the plant's design basis-accidents are no longer possible.
The few remaining design-basis accidents are not complex and do not warrant the continued application of control room design criteria.
i (C) Reaulatory Guide 1.97 reauirements for instrument installation. W'ith the plant in a i permanently shutdown and defueled condition, most of the postulated design-basis j accidents for which the Regulatory Guide 1.97 instrumentation was intended are no l longer possible. Additionally, the potential source term associated with the remaining ;
design-basis accidents to which the plant continues to be vulnerable has been l significantly reduced by more than 24 months of radioactive decay since the plant last :
operated. Therefore, Regulatory Guide 1.97 instrumentation is no longer warranted. I (D) Unarade of emeroency operatina orocedures. With the plant in a permanently shutdown and defueled condition, the postulated design-basis accidents upon which the emergency operating procedures were based are no longer possible.
i (E) Emeroency response facilities. With the plant in a permanently shutdown and defueled condition, most of the plant's postulated design-basis accidents are no longer possible. ,
The potential source term associated with the remaining design-basis accidents to which
r-
- ', .m the plant continues to be vulnerable has been significantly reduced by more than 24 '
months of radioactive decay since the plant last operated. Requirements associated with -
emargency response facilities are also contained in 10 CFR 50.47 and Appendix E to 10 CFR Part 50, for which MYAPC requested exemption in a separate request that the -
NRC granted in September 1998.
The staff has determined that because of the permanently shutdown and defueled status of the MYAPS facility the requirements of this order are no longer necessary for safe operation or maintenance of the plant. It is the staff's assessment that the rescission of this order does not pose any decrease in safety or any increase in the probability of accidents applicable in the permanently shutdown and defueled condition. Therefore, the staff finds rescission of the confirmatory order dated June 14,1984, acceptable.
Confirmatory Order dated Januarv 3.1996 -
This order required that MYAPC limit power to 2440 MWt until the NRC reviewed and approved an SBLOCA analysis. The order also required the submittal of an integrated containment analysis. The licensee has stated that the containment building is not required to be operable in the permanently defueled plant condition and that the requirement for this analysis should be removed. Also, although not explicitly stated by MYAPC, in accordance with 10 CFR s 50.82(a)(2), upon docketing of the MYAPC certifications of permanent cessation of operations and permanent removal of fuel from the reactor vessel, the 10 CFR Part 50 license no longer authorizes operation of the reactor or emplacement of fuel into the reactor vessel. Therefore, any limitations on maximum reactor power have become moot. Consequently, the NRC staff finds the rescission of the confirmatory order dated January 3,1996, acceptable.
3.0 CONCLUSION
The staff has determined that because of the permanently shutdown and defueled status of the MYAPS facility, these orders are no longer necessary for safe operation or maintenance of the plant. It is the staff's assessment that the changes proposed in the licensee's submittat do not pose any decrease in safety or any increase in the probability of accidents in the permanently shutdown and defueled condition. Therefore, the staff finds the rescission of the confirmatory orders dated July 10,1981, March 14,1983, June 14,1984, and January 3,1996, to be acceptable.
Principal Contributor: Michael Webb Date: July 6, 1999