ML19345H323
| ML19345H323 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 05/14/1981 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Morisi V BOSTON EDISON CO. |
| References | |
| NUDOCS 8105200109 | |
| Download: ML19345H323 (7) | |
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UNITED STATES V
NUCLEAR REGULATORY COMMISSION 3$.k)c([,nI wAsmwoTom, o. c. 20ssa (o
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May 14,1981 7/
en,cb Docket No. 50-293 g
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Mr. A. Victor Morisi, Manager Z
1,' AY 151981 * ~~ l Nuclear Operations Support Dept.
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comum Boston Edison Company M/C Nuclear A
y 800 Boylston Streat 47 Boston, Massachusetts 02199 m
Dear Mr. Morisi:
RE: Fire Protection - Appendix R (III G & L), Alternate Shutdown Capability By letters dated January 1,1980, August 15, 1980, September ll,1980, March 9,1981, March 18,1981 and by telephone comunications you provided information on an alternate safe shutdown system at Pilgrim I.
Enclosure No.1 provides our Interim Safety Evaluation. Our Final Safety Evaluation will be issued after our review of your submittal of the design descrip-tion required by 'O CFR 50.48(c)(5). You are requested to resolve the concerns raised in the enclosed evaluation. The schedule requirements for your response will be specified in our response to your March 9,1981 request for exemption from the submittal date requirement of 10 CFR 50.48 (c)(5).
Sincerely, OC W Thomas W. Ippolito, Chief Operating Reactors Branch #2 Division of Licensing l
Enclos ure:
l Interim Safety Eva'uation 1
cc w/ enclosure:
See next page 810s200/07
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1 Mr.-A. Victor Morisi Boston Edison Company cc:
Mr. Richard D. Machon Pilgrim Station Manager Boston Edison Company RFD #1, Rocky Hill Road Plymouth, Massachusetts 02360 Henry Herrmann, Esquire Massachusetts Wildlife Federation 151 Tremont Street Bcston, Massachusetts 02111 Plymouth Public Library North Street Plymouth, Massachusetts 02350 Resident Inspector c/o U. S. NRC P. O. Box 867 Plymouth, Massach'usetts 02360 2
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Enclosure l
INTERIM REPORT POST FIRE SHUTDOWN CAPABILITY PILGRIM NUCLEAR POWER PLANT Section 3.1.18 of the Fire Protection SER states that alternate shutdown capability independent of the cable spreading room (fire zone 3.2) will be provided. Section 3.2.1 and its referenced paragraphs in section 5 require that the licensee conduct an analysis of safety-relateo systems to demonstrate that fire related damage ir. any fire area will not inhibit the capability to safely shut down. Specific fire zones required in this analysis were 1.9, 1.10, 1.11, 1.22, 2.1, 2.2, 2.10, 3.5 and 3.10.
Section 3.2.7 states that the licensee will analyze the effects of postulated fire damage and provide modi-fication as necessary to the 125/250 volt 0.C. systems to preserve the plant's safe shutdown capability.
By submittals dated January 1980 and letters of August 15 and September
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11, 1980 and March 9 and 18,1981, the licensee addressed this concern. A conference call on April 10, 1981 between the licensee, NRC personnel and BNL provided further information. The submittals to date are not fir.el as the licensee has asked, in their letters of March 9 and 18,1981, fee an extension until October 31, 1981 to meet all the requirements of Appendix R Section t
III.G, including alternative shutdown capability evaluation.
1 This plant is a BWR, rated 655 MW and went into commercial operation in 1972. In their submittals, the licensee does not pick out specific systems for safe shutdown in the event of a fire, but rather relies on many different systems. For reactor coolant makeup, HPCI, RCIC, HPCS and LPSI are all noted.
i For decay heat removal, core spray, RBCCW and service water are noted. For pressure control, the ADS valves are used with a minimum of three required.
The RHR system in the suppression pool cooling mode is used with service water cooling. For cold shutdown, the RHR system in the shutdown cooling mode and ADS are called for. For the cable spreading room, alternate shutdown methods are given using manual operations at various local control stations. For all the other areas, few manual operations are called for and considerable reliance is placed on fire protection methods, including cable coating.
We have evaluated the Pilgrim post fire shutdoun capability using NRC guidelines " Staff Position, Safe Shutdown Capability" dated June 19, 1979 and NRC requirements in Section III.L of Appendix R to 10 CFR Part 50. We have found that:
1.
It has not been shown that the post-fire shutdown circuitry is 1
isolated from associated circuits.
Isolation should be such that fire damage to associated circuits in a fire area will not prevent the operation of shutdown equipment.
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2.
Support functions have not been adequately addressed in tenns of availability in case of a fire.
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i 3.
Process monitoring has not been adequately. addressed.
4.
Repair procedures for cold shutdown are not yet completed and repair material is not on site.
5.
On page 54 of the January 1980 submittal the licensee states that the loss of HPCI and RCIC must be avoided. This is contradicted on page 36 where the licensee gives an example of where HPCI and RCIC can be lost.
6.
There is a procedure in the January 1980 submittal for alternative shutdown for the cable spreading room. This is not yet a final procedure; there were no other procedures for alternative shutdown submitted with the documents reviewed.
7.
For a fire in the cable spreading room, three plant operators will be available to achieve alternative safe shutdown. However, the manpower requirements were not given for the other areas.
8.
The licensee has not stated in their submittals that cold shutdown can be achieved in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with the loss of offsite power.
9.
In section 2.1.5 of the submittal of January,1980 the licensee states that one of the redundant safety divisions in the cable spreading room is conservatively assumed to be functional during the initial period of 20 minutes from the time a fire is detected and the emergency shutdown procedure is initiated. The licensee has'not provided a basis for this assumption.
- 10. In their letter of September 11, 1980 the licensee refers to a loss of offsite power of only 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. If both DC motor control ccaters (MCC) D7 (RCIC) and D8 (HPCI and RHR) are lost in a common fire, both diesel generator fuel oil pumps will be lost; the day tank can supply fuel for only 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />.
- 11. One of the conclusions of the September 11, 1980 letter is that the January 1980 submittal shows that the loss of both MCC 07 and 08 loads will not jeopardize safe shutdown. However, the January 1980 submittal addresses the loss of MCC 07 by itself and not concur-rently with MCC 08. This earlier submittal states that the 250 volt DC system could be lost witn no effect on safe shutdown. No anal-ysis is given to back up the fact that support systems such as the HPCI turbine auxiliary oil pump would be lost with a sustained power outage.
- 12. The post fire shetdown capability depends heavily on fire protec-tion and spacial separation in the c'ntrol rod drive module areas east and west, the open areas of the reactor building west, the closed loop cooling water pump room A, the switch-gear rooms A and B, the feedwater heater room, the vital M-G set rooms and the cable spreading rooms. In many of these areas, the licensee relies heavily on the fire protection given by flame retardant coating.
In
all of these areas, and in the control room, the licensde has ap-plied for an exemption to the requirements of Section III G.(2). In his submittal of January 1980, the licensee treats fire zones 1.9 and 1.10 as separate zones even though there is no barrier between them. The licensee postulates a fire in only one of these areas at a time, but provides no justification for this, nor an analysis which demonstrates that both areas could be lost without adversely affecting plant safe shutdown capability. This is an item for re-view by NRC fire protection engineers.
We conclude that the proposed alternate shutdown capability for the Pilgrim Power Station does not conform with HRC guidelines and requirements and, therefore, is unacceptable.
We recommend the following:
A.
The alternative shutdown capability should be modified to meet the requirements of Section III L of Appendix R to 10 CFR Part 50, tak-ing into consideration the above findings.
B.
All support functions including lube oil, cooling, and power should be shown to be available for the equipment used in the alternative shutdown capability.
C.
The process monitoring should be shown to be capable of providing direct readings of the process variables necessary to control re-activi ty, reactor coolant makeup, and reactor heat removal. Penna-nently installed instruments should be used to provide capability for reading reactor water level, pressure and temperature, suppres-sion pool temperature and level, applicable flow rates, radiation levels, and core monitoring for neutron flux.
D.
All repair procedures for cold shutdown should be fully developed and it should be verified that the materials for the repairs are maintained on site. The repair materials should have sufficient quality control to assure that the repair will last throughout a sustained shutdown.
E.
The procedures for alternative hot and cold shutdown should be fully devel oped. The manpower for these procedures and for the repair procedures should be shown to be available on site and the work to be perfonned should be reasonable of the manpower available.
F.
The licensee should demonstrate that alternative safe shutdown l
capability can be achieved with the loss of offsite power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
G.
The licensee should demonstrate that the loss of the containment ventilation system would not affect safe shutdown in the event of a fi re.
H.
The manual operations required to achieve alternative safe shutdown should consider the radiation levels where the equipment is to be operated.
4 I.
The lic.ee should clarify the need for HPCI and RCIC systems for safe shutdown.
J.
The licensee should justify by analysis that safe shutdown capabil-ity will not be affected by the loss of both diesel fuel pumps when offsite power is unavailable for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
K.
The licensee should clarify his position on whether or not he can sustain the loss of both DC motor control centers D7 (RCIC) and D8 (HPCI). If these cannot be lost to a common fire, he should docu-ment the fire protection methods that will assure the integrity of at least one of the two systems.
L.
Section III.G of Appendix R to CFR Part 50 requires cabling for or associated with redundant safe shutdown systems necessary to achieve and maintain hot shutdown conditions be separated by fire barriers having a three hour fire rating or equivalent protection (see Sec-tion III.G.2 of Appendix R). Therefore, if option III.G.3 is chosen for the protection of shutdown capability, cabling required for or associated with the alternative method of hot shutdown for each fire area must be physically separated by the equivalent of a three-hour rated fire barrier from the fire area.
In evaluating an alternative shutdown method, associated circuits are circuits that cruld prevent operation or cause malfunction of the alternative train which is used to achieve and maintain hot shutdown conditions due to fire induced hot shorts, open circuits, or shorts to ground.
Safety related and nonsafety related cables that are associated with the equipment and cables of the alternative or dedicated method of shutdown are those that have a separation from the fire area less than that required by Section III.G.2 of Appendix R to 10 CFR 50 and have either (1) a common power source with the alternative shutdown equipment and the power source is not electrically protected from the post fire shutdown circuit of concern by coordinated circuit breakers, fuses, or similar devices, (2) a connection to circuits of equipment whose spurious operation will adversely effect the shut-down capability, e.g., RHR/RCS isolation valves or (3) a common en-closure, e.g., raceway, panel, junction box with alternative shut-l down cables and are not electrically protected from the post fire l
shutdown circuits of concern by circuit breakers, fuses, or similar devices.
For each fire area where an alternative or dedicated shutdown method, in accordance with Section III.G.3 of Appendix R 10 CFR Part 50 is provided by proposed modifications, the following information is required to demonstrate that associated circuits will not prevent i
operation or cause malfunction of the alternative or dedicated shut-down method.
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s (1) Provide a table that lists all equipment including instrumenta-tion and support system equipment that are required by the alternative or dedicated method of achieving and maintaining hot shutdown.
(2) For each alternative shutdown equipment listed in (1) above, provide a table that lists the essential cable (instrumenta-tion, control and power) that are located in the fire area.
(3) Provide a table that lists safety related and nonsafety related cables associated with the equipment in cables constituting the alternative or dedicated method of shutdown that are located in the fire area.
i (4) Show that fire induced failures of the cables listed in (2) and (3) above will not prevent operation or cause malfunction of the alternative or dedicated shutdown method.
(5) For each cable listed in (2) above provide a detailed electri-cal schematic drawing that shows how each cable is isolated i
from the fire area.
1 H.
The residual hea?. removal system is generally a low pressure system that interfaces with the high pressure primary coolant system. To preclude a LOCA through this interface, we require compliance with the recommendations of Branch Technical Position RSB 5-1.
Thus,.
this interface most likely consists of two redundant and independent motor operated valves. These two motor operated valves and their associated cable may be subject to a single fire hazard. It is our concern that this single fire could cause the two valves to open re-sultina; in a fire-initiated LOCA through the subject high-low pres-sure system interface. To assure that this interface and other high-low pressure interfaces are adequately protected from the ef-fects of a single fire, we require the following infomation:
Identify each high-low pressure interface that uses redundant electrically controlled devices (such as two series motor oper-i ated valves) to isolate or preclude nJpture of any primary cool-ant boundary.
Identify the device's essential cabling (oower and control) and describe the cable routing (by fire area) from source to temina-tion.
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Identify each location where the identified cables are separated by less than a wall he.ving a three-hour fire rating from cables for the redundant device.
For the areas identified in the above paragraph, provide the bases and justification as to the acceptability of the existing design or any proposed modidications.
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