ML20041D236
| ML20041D236 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/31/1982 |
| From: | Morken D EG&G, INC. |
| To: | Donohew J Office of Nuclear Reactor Regulation |
| References | |
| CON-FIN-A-6429 EGG-EA-5750, TAC-42126, NUDOCS 8203040607 | |
| Download: ML20041D236 (18) | |
Text
_
EGG-EA-5750 JANUARY 1982 TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY, RANCHO SEC0 NUCLEAR GENERATING
- SId A)(*/9 STATION, UNIT N0. 1 D. J. Morken act h e (L JA M &
PRELIMINARY U.S. Department of Energy Idaho Operations Office
- Idaho National Engineering Laboratory C
7 e t; D-1, % g ;
N 3, h, ' j
' r '!
~
~
,b6MgrK c
I "M.
^
m
?
II;Nh
(
,) _ ~ '" - r,
_ _ m'
- yg 55d@%t M4lir*T.1;> -: %(
I
'A W prg y
%@y % i [ _
y+ +
s s m - - - -- _ _
\\
(',e =,.
j gs c__
{
=f.
~b 27 (;
t 2
II t
,.W This is an informal report intended for use as a preliminary or working document Prepared for the U.S. Nuclear Regulatory Commission Under DOE Contract No. DE-AC07-76ID01570 FIN No. A6429 8203040607 020131 PDR RES 8203040607 PDR
hEGsG,......
FORM EG4G 390 INTERIM REPORT Accession No.
Report No.
EGG-EA-5750 C:ntract Program or Project
Title:
Selected Operating Reactur issues Program (Illi Subject of this Documents s
Technical Specifications for Redundant Decay Haat Removal Capability, Rancho Seco Nuclear Generating Station, Unit No. 1 Type of Document:
Informal Report Author (s):
D. J. Morken D;te of Document:
January 1982 Responsible NRCIDOE Individual and NRCIDOE Office or Division:
J. N. Donohew, Division of Licensing, NRC This document was prepared primarily for preliminary or internal use. it has not received full review and approval. Since there may be substantive changes, this document should not be considered final.
EG&G Idaho, Inc.
Idaho Falls, Idaho 83415 Prepared for the U.S. Nuclear Regulatory Cr. mission Washington, D.C.
Under DOE Contract No. DE-AC07-761D01570 NRC FIN No.
A6429 INTERIM REPORT
i 0033j TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY RANCHO SEC0 NUCLEAR GENERATING STATION, UNIT N0. 1 Docket No. 50-312 January 1982 D. J. Morken Reliability and Statistics Branch Engineering Analysis Division EG&G Idaho, Inc.
i' i
ABSTRACT l
In response to D. G. Eisenhut letter dated June 11, 1980, Sacramento Municipal Utility District submitted " Proposed Revisions to Technical l
Specifications" for the Rancho Seco Nuclear Generating Station Unit 1.
These proposed revisions would provide for redundancy in decay heat removal capability in all nodes of operation.
FOREWORD i
This report is supplied as part of the " Selected Operating Reactor Issues Program (III)" being conducted for the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Licensing, by EG&G Idaho, Inc., Reliability and Statistics Branch.
The U.S. Nuclear Regulatory Commission funded the work under the authorization, B&R 20-19-01-06, FIN No. A6429.
f 1
l 1
e 1
l l-1 I
i 11
CONTENTS
1.0 INTRODUCTION
I 2.0 REVIEW CRITERIA.................................................
1 3.0 DISCUSSIONS AND EVALAUTION......................................
1 3.1 Startup and Power Operations..............................
2 3.2 Hot Standby...............................................
2 3.3 S h u td o w n..................................................
2 3.4 Refnaling.................................................
3 4.0 CONCLU,, i.....................................................
3 5.0 R E F E R EN C E S......................................................
3 APPENDIX A--NRC MODEL TECHNICAL SPECIF ICATION........................
5 b
iii
T TECHNICAL EVALUATION REPORT TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY RANCHO SEC0 NUCLEAR GENERATING STATION, UNIT NO. I
1.0 INTRODUCTION
A number of events have occurred at operating PWR facilties where decay heat removal capability has been seriously degraded due to inadequate administrative controls during shutdown modes of operation.
One of these InIEBulletin80-12,gavis-occurred at the events, described in IE Information Notice 80-20, dated Besse, Unit No. I plant, on April 19, 1980.
May 9,1980, licensees were requested to immediately implement administra-tive controls which would ensure that proper means are available to provide redundant methods of decay heat removal. While the function of the bul-letin was to effect immediate action with regard to this problem, the NRC considered it necessary that an amendment of each license be made to pro-vide for permanent long-term assurance that redundancy in decay heat By letter dated June 11 1980 removal capability will be maintained.
allPWRlicenseeswererequestedtoproposeTechnicalSpecificaf. ions {TS) changes that provide for redundancy in decay heat removal capability in all modes of operation; use the NRC model TS which provide an acceptable solu-tion of the concern and include an appropriate safety analysis as a basis; and submit the proposed TS with the basis by October 11, 1980.
Sacramento Municipal Utility District (SMUD) submitted proposed revi-sions to their TS for Rancho Seco, Unit 1 for decay heat removal on October 27, 1980.4 2.0 REVIEW CRITERIA The review criteria for this task are contained in the June 11, 1980 letter from the NRC to all PWR licensees. The NRC provided the model tech-nical specifications (MTS)5 which identify the normal required redundant coolant system and the required actions when redundant systems are not available for a typical four-loop plant (Appendix A).
The general review criteria are:
1.
Two independent methods for 'scay heat removal are required in the plant TS for each operating mode.
2.
Periodic surveillece requirements should insure the operability of the systems.
3.0 DISCUSSION AND EVALUATION Rancho Seco Unit 1 is a two-loop, Babcock-Wilcox (B&W) PWR plant.
The Rancho Seco TS differ in format from the Nuclear Regulatory Commissions (NRC) MTS for B&W PWRs. Limiting conditions for operation start with Sec-i-
tion 3 of the Rancho Seco TS.
Section 3 does not delineate the limiting l
. conditions by applicable modes as in the MTS.
The modes identified in this 1
1 l
f
report are based on definitions found in Section 1 of Rancho Seco TS.
Similarly, section 4 of the Rancho Seco TS does not define the surveillance requirements based on applicable modes.
3.1 Startup and Power Operation--Modes 1 and 2 (Toperating)
SMUD's present TS6 requires that both reactor coolant loops and both reactor coolant pumps be in operation at startup or at full power. With i
one coolant pump not in operation, the current Rancho Seco TS requires a decrease to 75% of full operating power. This is in agreement with the MTS. The following reactor protection system monitors reduce setpoints automatically upon loss of a coolant pump:
A.
Nuclear overpower based on reactor coolant flow and axial power imbalance.
B.
Nuclear overpower based on pump monitors.
The Rancho Seco TS do not require the setpoints for nuclear overpower flux monitors to be reduced.
The proposed Rancho Seco TS do not contain requirements for surveil-lance of the coolant loops and coolant pumps on a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> basis or require verification of the reactor protection system setpoint changes within a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period.
3.2 Hot Standby--Mode 3 (T
>525*F and Keff = 1.00) ave No changes to the existing Rancho Seco TS are proposed by SMUD for moge3. The accompanying letter to the proposed Amendment 74 to Rancho Seco TS states the requirements are already met in Sections 3.1.1.2A, 3.4 and l
3.1.1.1B of the existing Rancho Seco TS.
Section 3.1.1.2A requires one steam generator to be operable whenever the reactor coolant temperature is above 280*F.
Section 3.4 identifies the systems that must be capable of supplying feedwater to the steam generator.
Section 3.1.1.lB restricts dilution of boron concentration in the reactor coolant system unless at least one reactor coolant pump or one decay heat removal (DHR) pump is operating.
No mention is made of having both coolant loops and one coolant pump in each loop operable, which is a requirement of the MTS.
The requirements for surveillance were not included in the proposed amendment 74 or Section 4 of the existing Rancho Seco TS.
3.3 Shutdown--Mode 4 (TAVG>525*F), Mode 5 (TAVG4200*F),Keff10.99 The proposed Rancho Seco TS satisfy the requirements for the shutdown modes 4 and 5.
The proposed TS do not specifically require having at least one of the coolant loops in operation. However, the bases for the require-e ments states that "when T is below 280*F a single reactor coolant loop orDHRloopprovidessuffbentheatremovalcapabilityforremovingdecay 2
i
l heat." Further, a reactor coolant pump or DHR pump is required to be in operation before boron concentration is reduced by dilution wit 5 makeup water.
Neither the proposed Amendment No. 74 nor Section 4 of the eristing Rancho Seco TS contain requirements for surveillance of the operability of the DHR, reactor coolant pumps or the steam generator loops as identified in the MTS.
3.4 Refueling Operations--Mode 6 A proposed change to the Rancho Seco TS will require two OHR pumps and coolant loops to be operable when the transfer canal water is above 37 ft.
The bases include the proposed modification to the Rancho Seco TS that states at least one DHR loop will be in operation to ensure that:
(1) suf-ficient cooling capacity is available to remove decay heat and maintain water in the reactor pressure vessel below 140 F, and; (2) sufficient cool-ant circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.
Rancho Seco TS require the containaent isolation valves to be operable but do not require closing all penetration within a time period as required in the MTS.
Neither the proposed amendment No. 74 nor Section 4 of the existing Rancho Seco TS contains the requirements for surveillance to verify a DHR loop is operating and circulating reactor coolant flow as required in the j
MTS.
4.0 CONCLUSION
S The Rancho Seco existing and proposed TS do not agree with the MTS in the following areas:
(1)
It does not follow the MTS format in defining'the limiting condi-tions by applicable modes, (2)
It differs from the MTS in Modes 1 and 2 by not requiring reduc-tion of nuclear power monitor setpoints when operating with less than four coolant pumps, (3) Mode 3 does not require having both coolant loops and one coolant pump in each loop operable, (4) Mode 6 does not require closing of containment penetrations when less than one DHR loop is operating, (5)
Neither the proposed Amendement 74 nor Section 4 of the existing Rancho Seco TS require the surveillance as identified in the MTS in Modes 1 through 6.
i
5.0 REFERENCES
l 1.
NRC Information Notice 80-20, May 8,1980.
i I
3
2.
NRC IE Bulletin 80-12, May 1980.
3.
NRC letter, D. G. Eisenhut, To All Operating Pressurized Water Reac-tors (PWR's), dated June 11, 1980.
4.
SMUD letter, J. J. Mattimoe to NRC, D. G. Eisenhut, " Proposed Amend-ment No. 74", dated October 27, 1981.
5.
Standard Technical Specifications for Babcock and Wilcox Pressurized Water Reactors, NUREG-0103-Rev. 3, July 1979.
6.
Appendix A to Operating License No. DPR-54, Technical Specifications for the Rancho Seco Unit 1, Sacramento Municipal Utility District, dated May 19, 1976.
m O
4
)
r l
i s
e 9
APPENDIX A MODEL TECHNICAL SPECIFICATIONS FOR REOUNDANT DECAY HEAT REMOVAL FOR BABC0CK & WILC0X PRESSURIZED WATER REACTORS (PWR's) 4 5
r 3/4.4 REACTOR COOLANT SYSTEM 3/4.4.1 COOLANT LOOPS AND COOLANT CIRCULATION STARTUP AND POWER OPERATION LIMITING CONDITION FOR OPERATION 3.4.1.1 Both reactor coolant loops and both reactor coolant pumps in each loop shall be in operation.
APPLICABILITY: MODES 1 and 2.*
ACTION:
With one reactor coolant pump not in operation, STARTUP and POWER OPERATION may be initiated and may proceed provided THERMAL POWER is restricted to less than ( )% of RATED THERMAL POWER and within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> the setpoints for the following trips have been reduced to the values specified in Specification 2.2.1 for operation with three reactor coolant pumps operating:
i 1.
(Nuclear Overpower).
2.
(Nuclear Overpower based on RCS flow and AXIAL POWER IMBALANCE).
3.
(Nuclear Overpower based on pump monitors).
SURVEILLANCE REQUIREMENT 4.4.1.1 The above required reactor coolant loops shall be verified to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
4.4.1.2 The Reactor Protective Instrumentation channels specified in the applicable ACTION statement above shall be verified to have had their trip setpoints changed to the values specified in Specification 2.2.1 for the
~
applicable number of reactor coolant pumps operating either:
a.
Within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after switching to a different pump combination if the switch is made while operating, or b.
Prior to reactor criticality if the switch is made while shutdown.
i See Special Test Exception 3.10.4.
7
REACTOR COOLANT SYSTEM HOT STANDBY LIMITING CONDITION FOR OPERATION 3.4.1.2 a.
The reactor coolant loops listed below shall be OPERABLE:
1.
Reactor Coolant Loop (A) and its associated reactor coolant pump, 2.
Reactor Coolant Loop (B) and its associated reactor coolant pump, b.
At least one of the above Reactor Coolant Loops shall be in operation.*
APPLICABILITY: MODE 3 ACTION:
a.
With less than the above required reactor coolant loops OPERABLE, restore the required loops to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, b.
With no reactor coolant loop in operation, suspend all operations involving a reduction in boron concentration of the Reactor Coolant System and immediately initiate action to return the required coolant loop to operation.
S_URVEILLANCE REQUIREMENT 4.4.1.2.1 At least the above required reactor coolant pumps, if not in operation, shall be determined to be OPERABLE once per 7 days by verifying correct breaker alignments and indicated power availability.
4.4.1.2.2 At least one cooling loop shall be verified to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
0 All reactor coolant pumps may be de-energized for up to I hour provided (1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and (2) core outlet temperature is maintained at least 100F below saturation temperature.
8 c.
REACTOR COOLANT SYSTEM SHUTDOWN LIMITING CONDITION FOR OPERATION 3.4.1.3 a.
At least two of the coolant loops listed below shall be OPERABLE:
1.
Reactor Coolant Loop (A) and its associated steam gen-erator and at least one associated reactor coolant pump, 2.
Reactor Coolant Loop (B) and its associated steam gen-erator and at least one associated reactor coolant pump, 3.
Decay Heat Removal Loop (A),*
4.
Decay Heat Removal Loop (B),*
b.
At least one of the above coolant loops shall be in opera t ion. **
APPLICABILITY: MODES 4 and 5.
ACTION:
4 With less than the above required loops OPERABLE, immediately a.
initiate corrective action to return the required loops to OPERABLE status as soon as possible; be in COLD SHUTDOWN within 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />, b.
With no coolant loop in operation, suspend all operations involving a reduction in boron concentration of the Reactr~
Coolant System and immediately initiate corrective action to return the required coolant loop to operation.
I j
The nornal or emergency power source may be inoperable in MODE 5.
All reactor coolant pumps and decay heat removal pumps may be de-energized for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> provided (1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and (2) core outlet temperature is maintained at least 10 F below saturation 0
temperature.
l 9
l
1 REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENT 4.4.1.3.1 The required residual heat removal loop (s) shall be determined OPERABLE per Specification 4.0.5.
4.4.1.3.2 The required reactor coolant pump (s), if not in operation, shall be determined to be OPERABLE once per 7 days by verifying correct breaker alignments and indicated power availability.
4.4.1.3.3 The required steam generator (s) shall be determined OPERABLE by verifying secondary side level to be greater than or equal to (
)%.
4.4.1.3.4 At least one coolant loop shall be verified to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
4 0
h 10
REFUELING OPERATIONS 3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRCULATION ALL WATER LEVELS LIMITING CONDITION FOR OPERATION 3.9.8.1 At least one residual heat removal (DHR) loop shall be in operation.
APPLICABILITY:
MODE 6 O
ACTION:
a.
With less than one DHR loop in operation, except as provided in
- b. below, suspend all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of
._. - _ ~,._..--the Reactor Cool ant System.
Close all containment penetrations providing direct access from the containment atmosphere to the outside atmosphere within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
b.
The DHR loop may be removed from operation for up to I hour per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period during the performance of CORE ALTERATIONS in the j
vicinity of the reactor pressure vessel (hot) legs.
i t
c.
The provisions of Specification 3.0.3 are-not applicable.
SURVEILLANCE REQUIREMENT 4.9.8.1 At least one DHR loop shall be verified to be in operation and circulating reactor coolant at a flow rate of greater than or equal to (2800) gpm at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
d i
11
l REFUELING OPERATIONS LOW WATER LEVEL LIMITING CONDITION FOR OPERATION i
3.9.8.2 Two independent DHR loops shall be OPERABLE.*
APPLICABILITY: MODE 6 when the water level above the top of the irradiated fuel assemblies seated within the reactor pressure vessel is less than 23 feet.
i ACTION:
a.
With less than the required DHR loops OPERABLE, immediately initiate corrective action to return the required loops to 1
OPERABLE status as soon as possible.
b.
The provisions of Specification 3.0.3 are not applicable.
SURVEILLANCE REQUIREMENT 4.9.8.2 The required DHR loops shall be determined OPERABLE per Specifica-tion 4.0.5.
4 i
i I
i i
- The normal or emergency power source may be inoperable for each DHR loop.
12
3/4.4 REACTOR COOLANT SYSTEM BASES 3/4.4.1 COOLANT LOOPS AND COOLANT CIRCULATION The plant is designed to operate with both reactor coolant loops in operation, and maintain DNBR above (1.32/1.30) during all normal operations and anticipated transients. With one reactor coolant pump not in operation in one loop, THERMAL POWER is restricted by the Nuclear Overpower Based on RCS Flow and AXIAL POWER IMBALANCE and the Nuclear Overpower Based on Pump Monitors trip, ensuring that the DNBR will be maintained above (1.32/1.30) at the maximum possible THERMAL POWER for the number of reactor coolant pumps in operation or the local quality at the point of minimum DNBR equal to (22/15)%, whichever is more restrictive.
In MODE 3, a single reactor coolant loop provides sufficient heat removal capability for removing decay heat; however, single failure con-siderations require that two loops be OPERABLE.
In MODES 4 and 5, a single reactor coolant loop or DHR loop provides sufficient heat removal capability for removing decay heat; but single failure considerations require that at least two loops be OPERABLE.
- Thus, if the reactor coolant loops are not OPERABLE, this specification requires two DHR loops to be OPERABLE.
The operation of one Reactor Coolant Pump or one DHR pump provides adequate flow to ensure mixing, prevent stratification and produce gradual reactivity changes during boron concentration reductions in the Reactor Coolant System. The reactivity change rate associated with boron reduction will, therefore, be within the capability of operator recognition and control.
e 13
REFUELING OPERATIONS BASES 3/4.9.8 DECAY HEAT REMOVAL AND COOLANT CIRCULATION The requirenent that at least one DHR loop be in operation ensures that (1) sufficient cooling capacity is available to renove decay heat and 0
maintain the water in the reactor pressure vessel below 140 F as required during the REFUELING MODE, and (2) sufficient coolant circulation is main-tained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.
The requirement to have two DHR loops OPERABLE when there is less than 23 feet of water above the core ensures that a single failure of the oper-ating DHR loop will not result in a complete loss of decay heat removal capab il ity. With the reactor vessel head removed and 23 feet of water above the core, a large heat sink is available for core cooling. Thus, in the event of a failure of the operating DHR loop, adequate time is provided to initiate emergency procedures to cool the core.
6 D
14 I
.