ML19345B045
| ML19345B045 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/14/1980 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | METROPOLITAN EDISON CO. |
| Shared Package | |
| ML19345B041 | List: |
| References | |
| ISSUANCES-OLA, NUDOCS 8011260027 | |
| Download: ML19345B045 (11) | |
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I UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of METROPOLITAN EDISON COMPANY, g d.
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Docket No. 50-320 OLA
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(Three Mile Island Nuclear Station,
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Unit 2)
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AMENDMENT OF ORDER 1
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Metropolitan Edison Company, Jersey Central Power and Light Company and Pennsylvania Electric Company (collectively, the Licensee) are the holders of Facility Operating License No. DPR-73, which had authorized operation of i
the Three ?'ile Island Nuclear Station, Unit 2 (TMI-2) at power levels up to 2772 megawatts themal.
The f acility, which is located in Londonderry Townshio, Dauphin County, Dennsylvania, is a pressured water reactor pre-viously used for the commercial generation of electricity, i
By Order for Modification of License, dated July 20, 1979, the Licensee's 1
authority to oDerate the facility was suspended and the Licensee's authority was li'nited to raintenance of the facility in the present shutdown cooling mode (at F.R. 45271). By further Order c.? tne Director, Office of Nuclear Reactor Regulation, dated February 11, 1980, a new set of femal license requirements was imposed to reflect the post-accident condition of the 80112.600 6
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, I facility and to assure the continued maintenance of the current safe, stable, long-term cooling condition of the facility (45 F.R.11282). These require-i ments, in the form of proposed Technical Specifications, would modify the i j facility operating license so as to:
(1) define operating parameters for the current safe, stable, long-term cooling mode for the facility (defined as the recovery mode), and delete all other permissible operating modes so as to assure that operation of the facility in other than the stable shutdown condition of the recovery mode is precluded; (2) impose functional, operability, redundancy and surveillance requirements as well as safety limits and limiting concitions with regard to those structures, systems, equipment and components necessary to maintain the facility in the current i
safe, stable shutdown condition and to cope with foreseeable off-normal conditions; (3) prohibit venting or purging or other treatment of [the approxi-mately 57,000 curies of krypton-85 in] the reactor building l
atmosphere, the discharge of water decontaminated by EPICOR-II system, and the treatment and disposal of high-level radio-actively contaminated water in the reactor building, until each of these activities has been approved by the NRC,1/
consistent with the Cor. mission's State ent of Policy and hotice of Intent to Prepare a Programmatic Environmental Impact Statement (44 F.R. 67738).
On the basis of the public health, safety, and interest, the requirements of the proposed Technical Specifications, attached to the February 11,1980 Order, w?re made effective imrediately.
Under the terms of the Order, since requests l
for a hearing are pending before an Atomic Safety and Licensing Board, the proposed formal license amendment -incorporating these proposed Technical a
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- i jf 5y Memorancum and Order, dated June 12, 1980, the Comr.fssion gave the d
approval contemplated by this restriction insofar as necessary for the Licensee to conduct a purging of the TMI-2 containt.ent in accordance with procedures approved by the NRC. CL I-80-25. This activity was completed on July 11, 1980.
. t Specifications will becore effective, in the event a hearing is granted, on the date specified in an order made following the hearing or, upon other final disposition of such proceeding.
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II.
Following the March 28, 1979 accident at TMI-2, it became necessary in late
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April 1979 to alter the preferred cooling mode for the reactor by a transition j
from use of forced circulation by the reactor coolant system pumps to natural convection circulation, i
By letters dated July 31,1980 (Reference 1) and August 5,1980 (Reference 2),
o the Metropolitan Edison Company (licensee) proposed changes to the Recovery 1
Moce technical specifications for Three Mile Island Unit 2 ' MI-2) providing for tne imple entation of the Mini Decay Heat Removal 5 stem (M3 HRS) for lon;-tem core coolin;.
although several nodes fte re oving decay heat would be available, the MDHRS woulc provida ; forced flow system for removing decay heat from the TMI-2 reactor fuel. Accordingly, the proposed changes would impose operability requirements for the MDHRS and would also delete the operability requirements for certain Balance of Plant (30P) systems which have been used since the March 28, 1979, accident, but would no longer be required, for removing the decay heat. The operability requirements for these 80? systems had been imposed by the Order of the Director of the
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Office of Nuclear Reactor Regulation on February 11,19'n (45 F.R.11282) in the fom of proposed Technical Specifications.
The proposed change would make available a newly installed MDHRS to remove l
decay heat rather than the present method which accomplishes this function by using the."A" steam generator in a steaming mode to the condenser.
The licensee's proposal required certain modifications to meet our recuirements.
With the incorporation of these staff required modifications, we have found the proposal to be an acceptable method for removing the decay heat and have therefore granted the licensee's request to modify the method used for long tem core cooling.
The TMI-2 Reactor Coolant System (RCS) is currently operating in a natural circulation heat removal mode with heat rejection from it being accomplisned by botn loss to ambient (reactor at.mosphere and sump water) and through the "A" steam generator.
The reactor building is in turn being coole: by the reactor building fan coolers while the "A" steam generator is steaming to the condenser through the turbine bypass valve.
This mode of core cooling-has been in effect since late April 1979. With passage of time and the associated redu: tion of decay heat generation rate (presently approximately 75 kw), the natural circulation #10w has changed from continuous to cyclic with increasing intervals between the cyclic flow " burps".
Feat rejection through the "A" steam generator by steaming to the condenser recuires the operation of several major S0psystems including: circulating 1
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5-nater syster, nain steam system and the "A" steam generator, condensate and feedwater systems, main condenser and package boiler.
Conversion to and use of the MDHRS for core cooling would simplify the plant operations since use of the MDHRS would eliminate the need for operating the previously noted SDP systers.
The MDHRS is classified as a nonsafety grade system but it is designed and installed to seismic Category I requirements up to and including the seccnd isolation valve in its supply and discharge lines.
The balance of the system is designed and installed to Operating Basis Earthquake requirements.
The MDHRS takes suction from the "B" loop of the Decay Heat System (DH) outlet frcr tre reactor vessel via a connection to the Alternate Decay Heat Remos al Syrtem ( ADH).
Af ter passing through one of the MDHRS's parallel heat exchangers and pumps, the reactor coolant is returned to the reactor coolant syste *nrough the "B" Core Floeding injection no::le via a conne-tion te tne ADH and DH systems.
Connection of the Ali to the DH was evaluated and accroved in NUREG-0557 The MDHRS is sized such that one pump and one heat exchanger (two of each are installed) could remove up to approximately 1 MW of decay heat.
Therefore the MDHRS has more than adequate cooling capacity for removing the present and futuc9 decay heat roacs.
The MDMES would be cooled by *.he Nuclear Services Closec Cycle Cooling System which is reouired to be operable by proposed Technical Specification 3.7.3.1.
The power supply for the MDHRS pumps and motor operated valves is from redundant Class 1E busses which would be manually loaded on the Class IE diesel generators in the event of a loss of off-site power.
. In the event the MDHRS is not used er becores inoperable, backup cooling modes are available for removing the decay heat from the RCS.
These backup cooling mdes include the long tem "B" steam generator cooling system and
" Loss to Ambient." The long tem "B" stearn generator cooling system has been previously evaluated and its operability would continue to be required by proposed Technical Specification 3.7.1.
The NRC staff has reviewed the licensee's results of the " Loss to Ambient" cooling node and has perfomed an independent analysis, the results of which are in agreement with the licensee's conclusion. Therefore, we have concluded that any one of these cooling n'ethods provides an acceptable means for long term cooling of the reactor core. The staf f's overall evaluation of the MDHRS is presented in tne concurrently issued Saf ety Evaluation Report (SER).
The W HRS has a design pressure of 235 psig. Therefore, consideration was giver. to possible sources of overoressuri:ation of the C 'RS.
Three poten-tial sources of MDHRS overpressurization were ider,tifiec. These sources (1) Makeup pump operation with MDHRS in operation, (2) Pressuri:er were:
heater operation and (3) Maifunction of the Standby Pressure Control (SPC)
System.
To preclude operation of a r.akeup purp during operation of the MDHRS, the licensee proposed to delete the recuirement for an operable makeup pump from the proposed Technical Specifications but to retain the option to operate the pump for certain operations (e.g., degassing).
The licensee further
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7-stated that the electrical power supply circuit breakers for the makeup i
pumps would be racked out" when valve DH-V1 or DH-V171 is open.
Since d
operation of a makeup pump may be required in ene or more of the backup p
cooling modes or for degassing operations, we will retain a requirement for its operability in preposed Technical Specification 3.1.1.1.
- However, to provide assurance that the MDHRS will not be overpressurized due to l
operation of a makeup pump, we propose to add a recuirement to proposed Technical Specifications 3.1.1.1 that all makeup pumps be made inoperable when valve DH-V1 or DH-V171 is open by " racking out" their electrical power supply circuit breakers. We wocid also 7 4d a surveillance requirement to i
the Recovery Operations Plan to periodically verify that these breakers are
" racked out."
These actions provide assurance that the MDHRS would not be overpressurized due to operation of the makeup pumps.
Operation of the pressurizer heaters while operating the R S in a ater solid node with the ICHRS in operation creates the potential for overpres-surization of the MDHRS due to volumetric expansion of the reactor coolant as a result of heat input to the reacter coolant.
The licensee has cal-2 i culated that the electrical energi:ation of all the pressurizer heaters l
(1638 kw) would result in a volumetric expansion on the reactor coolant which would require a compensating relief capacity of '-
gr. m.
The MDMRS has an installed relief valve capacity of 53.5 cr"-
tat NRC staff has reviewed the licensee's result of this potentia aver,, osurization event
~and has perforced an indeper. dent check, the results of which a.*g in agree-ment with the licensee's conclusion.. Therefore, we agree that operation cf l
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. 1 the pressurizer heaters while operating the MDHRS with a water solid RCS would not result in overpressurization of the MDHRS.
Overpressurization of the MDHRS due to a malfunction of the SPC system has s
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i been precluded by reducing the SPC in-service nitrogen bank pressure to a new operating range of 225 to 400 psig~ and by the installation of a SPC systems pressure relief valve (SPC-R14) which has been set to provide overpressure relief if che SPC system pressure exceeds 125 psig which is substantially below the MDHRS design pressure of 235 psig. The change in 4
the nitrogen bank pressure was approved on July 25,1980 (Reference 3).
i The licensee also proposed deleting from proposed Technical Specifica-t tion 3.1.1.1 the requirenents for t boric acid storage system and an asso-ciated flow pata to the RCS. We have reviewed this proposed change and since redundant boron injection flow paths from the BWST to the RCS via the makeup pump an? cecay heat removal pump exist, we find the pecposed change acceptable.
The licensee's proposed Technical Specification for the MDHRS would require only one operable MDHRS pump nd heat exchanger with an action statenent providing instructions to be taken in the event of their inoperability.
Our position is that this Technical Specification should require the operability of both MDHRS pumps and heat exchangers and the associated flow path and that applicable action statenents should be supplied dealing with the i
inoperability of the various conponents in the MDHRS. The staff's position
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I is consistent with the operability requirements for similar systens (e.g.,
-proposed Technical Specifications 3.7.2.1, 3.7.3.1 and 3.7.4.1) in which i
the redundant systems are required operable and action statements are pro-
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vided for when one or both systems are inoperable.
Unless both MDHRS pumps are required operable and periodically demsostrated so in accordance with applicable surveillance requirements, there is no assurance of the operability of the redundant pump should its use be required for any reason. We have therefore modified the Technical Specification proposed for the MDHRS to be in accordance with our position. The licensee has agreed with our position on this matter.
We have also added appropriate surveillance reouirements I
to the Operations Recovery Plan to periodically demonstrate the operability of the MLHRS.
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l Ine Licensee also proposed to delete from proposed Technical Specifica-tien 3.8.2.1, the operability requirements for several electrical power 5usses.
Its basis for proposing to celete these requirements was tnat they supplied electrical power to the various 80P systems which were proposed for deletion from the proposed Technical Specifications upon incorporation of the MDHRS. However, in our review of these proposed changes, we deter-I-
mined that four of the busses proposed for deletion (480 volt Busses 2-35, 2-36, 2-45 and 2-46) also supplied electrical power to the auxiliary build-ing and the fuel handling building air cleanup systems which are in turn required operable per proposed Technical Sepcification 3.9.12.
Therefore, to ensure the electrical power supply for these air cleanup systems, we
. have retained the oc-' ability requirements for these four busses in proposed Technical Specification 3.8.2.1.
The licensee has agreed that the opera-bility requirements ar these four busses should be retained in proposed j
Technical Specification 3.8.2.1.
We agree that the operability repuirements for the other busses can be deleted from tne proposed Technical Specifica-tions as proposed by the licensee since the other busses proposed for dele-tion do not supply electrical power to any systems required for maintain-ing the plant in its safe shutdown condition.
Based on the staff's review of accident considerations, as presented in the SER, the staff has concluded that use of the MDHRS does not increase tne probablity or consequences of an accident or malfunction previously considered or reduce a margin of safety, and, thus, does not involve a signi#icant hazards consideration.
Indeed, as described above, the staff considers that the use and availability of the MOHRS will enhance the licensee's ability to maintain the reactor in a safe shutdown cooling node by providing a simplified and aporopriately sized decay heat removal system.
We have also determined that the modification does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having mace this deter-mination, we have further concluded that the modification involves an action which is insignificant from the standpoint of environnental impact and, pursuant to 10 CFR Section 51.5(d)(4), that an environmental impact state-ment or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the modification, f
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. III.
Accordingly, pursuant to the Atomic Energy Act of 1954, as amended, the Director's Order of February 11, 1980 is hereby revised to incorporate the celetions, additions and modifications set forth in Attachment A hereto.
For furtner details with respect to this action, see (1) Letter to B. Snyder, USNRC, from R. C. Arnold, Met. Ed/GPU, Technical Specification Change Request No. 24, da ted July 31,1980, (TLL 372); (2) Letter to B. Snyder, USNRC, frm R. C. Arnold, Met. Ed/GPU, Technical Specification Change Request No. 24, da ted August 5,1980, (TLL 382); (3) Letter to R. C. Arnold, Met. Ed/GPU, from Jct.n T. Collins, USNRC, TMI-2 Recovery Operations Plan Change Reques:
No. 4, da ted July 25,1980, (NRC/TMI-SG-115); and (4) the Director's Order of February 11, 1980.
All of :ne above docu ents are available for inspection at the Commissior.'s Public Document Room,1717 H Street, N.W., Washington, D.C., and at the Commission's Local Public Document Room at the State Library of Pennsylvania, Government Publications Section, Education Building, Commonwealth and Walnut Streets, Harrisburg, Pennsylvania 17126.
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j FOR THE NUCLEAR REGULCORY COMMISSION Harold R. Denton, Director Office of Nuclear Reactor Regulation Effective date:
November 11., 1980 Dated at Bethesda, Marylanc